src/BeOS/main_beos.cpp

/*
 *  main_beos.cpp - Emulation core, BeOS implementation
 *
 *  SheepShaver (C) 1997-2005 Christian Bauer and Marc Hellwig
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 *  NOTES:
 *
 *  SheepShaver uses three run-time environments, reflected by the value of XLM_RUN_MODE.
 *  The two modes which are also present in the original MacOS, are:
 *    MODE_68K - 68k emulator is active
 *    MODE_NATIVE - 68k emulator is inactive
 *  In the original MacOS, these two modes have different memory mappings and exception
 *  tables. Under SheepShaver, the only difference is the handling of interrupts (see below).
 *  SheepShaver extends the 68k emulator with special opcodes (EMUL_OP) to perform faster
 *  mode switches when patching 68k routines with PowerPC code and adds a third run mode:
 *    MODE_EMUL_OP - 68k emulator active, but native register usage
 *
 *  Switches between MODE_68K and MODE_NATIVE are only done with the Mixed Mode Manager
 *  (via nanokernel patches). The switch from MODE_68K to MODE_EMUL_OP occurs when executin
 *  one of the EMUL_OP 68k opcodes. When the opcode routine is done, it returns to MODE_68K.
 *
 *  The Execute68k() routine allows EMUL_OP routines to execute 68k subroutines. It switches
 *  from MODE_EMUL_OP back to MODE_68K, so it must not be used by native routines (executing
 *  in MODE_NATIVE) nor by any other thread than the emul_thread (because the 68k emulator
 *  is not reentrant). When the 68k subroutine returns, it switches back to MODE_EMUL_OP.
 *  It is OK for a 68k routine called with Execute68k() to contain an EMUL_OP opcode.
 *
 *  The handling of interrupts depends on the current run mode:
 *    MODE_68K - The USR1 signal handler sets one bit in the processor's CR. The 68k emulator
 *      will then execute the 68k interrupt routine when fetching the next instruction.
 *    MODE_NATIVE - The USR1 signal handler switches back to the original stack (signals run
 *      on a separate signal stack) and enters the External Interrupt routine in the
 *      nanokernel.
 *    MODE_EMUL_OP - The USR1 signal handler directly executes the 68k interrupt routine
 *      with Execute68k(). Before doing this, it must first check the current 68k interrupt
 *      level which is stored in XLM_68K_R25. This variable is set to the current level
 *      when entering EMUL_OP mode. Execute68k() also uses it to restore the level so that
 *      Execute68k()'d routines will run at the same interrupt level as the EMUL_OP routine
 *      it was called from.
 */

#include <Path.h>
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "sysdeps.h"
#include "main.h"
#include "version.h"
#include "prefs.h"
#include "prefs_editor.h"
#include "cpu_emulation.h"
#include "emul_op.h"
#include "xlowmem.h"
#include "xpram.h"
#include "timer.h"
#include "adb.h"
#include "video.h"
#include "sys.h"
#include "macos_util.h"
#include "rom_patches.h"
#include "user_strings.h"

#include "sheep_driver.h"

#define DEBUG 0
#include "debug.h"

// Enable Execute68k() safety checks?
#define SAFE_EXEC_68K 0

// Save FP regs in Execute68k()?
#define SAVE_FP_EXEC_68K 0

// Interrupts in EMUL_OP mode?
#define INTERRUPTS_IN_EMUL_OP_MODE 1

// Interrupts in native mode?
#define INTERRUPTS_IN_NATIVE_MODE 1


// Constants
const char APP_SIGNATURE[] = "application/x-vnd.cebix-SheepShaver";
const char ROM_FILE_NAME[] = "ROM";
const char ROM_FILE_NAME2[] = "Mac OS ROM";
const char KERNEL_AREA_NAME[] = "Macintosh Kernel Data";
const char KERNEL_AREA2_NAME[] = "Macintosh Kernel Data 2";
const char RAM_AREA_NAME[] = "Macintosh RAM";
const char ROM_AREA_NAME[] = "Macintosh ROM";
const char DR_CACHE_AREA_NAME[] = "Macintosh DR Cache";
const char DR_EMULATOR_AREA_NAME[] = "Macintosh DR Emulator";
const char SHEEP_AREA_NAME[] = "SheepShaver Virtual Stack";

const uint32 SIG_STACK_SIZE = 8192;                     // Size of signal stack

const uint32 MSG_START = 'strt';                        // Emulator start message


// Application object
class SheepShaver : public BApplication {
public:
        SheepShaver() : BApplication(APP_SIGNATURE)
        {
                // Find application directory and cwd to it
                app_info the_info;
                GetAppInfo(&the_info);
                BEntry the_file(&the_info.ref);
                BEntry the_dir;
                the_file.GetParent(&the_dir);
                BPath the_path;
                the_dir.GetPath(&the_path);
                chdir(the_path.Path());

                // Initialize other variables
                sheep_fd = -1;
                emulator_data = NULL;
                kernel_area = kernel_area2 = rom_area = ram_area = dr_cache_area = dr_emulator_area = -1;
                emul_thread = nvram_thread = tick_thread = -1;
                ReadyForSignals = false;
                AllowQuitting = true;
                NVRAMThreadActive = true;
                TickThreadActive = true;
                memset(last_xpram, 0, XPRAM_SIZE);
        }
        virtual void ReadyToRun(void);
        virtual void MessageReceived(BMessage *msg);
        void StartEmulator(void);
        virtual bool QuitRequested(void);
        virtual void Quit(void);

        thread_id emul_thread;          // Emulator thread
        thread_id nvram_thread;         // NVRAM watchdog thread
        thread_id tick_thread;          // 60Hz thread

        KernelData *kernel_data;        // Pointer to Kernel Data
        EmulatorData *emulator_data;

        bool ReadyForSignals;           // Flag: emul_thread ready to receive signals
        bool AllowQuitting;                     // Flag: Alt-Q quitting allowed
        bool NVRAMThreadActive;         // nvram_thread will exit when this is false
        bool TickThreadActive;          // tick_thread will exit when this is false

        uint8 last_xpram[XPRAM_SIZE]; // Buffer for monitoring XPRAM changes

private:
        static status_t emul_func(void *arg);
        static status_t nvram_func(void *arg);
        static status_t tick_func(void *arg);
        static void sigusr1_invoc(int sig, void *arg, vregs *r);
        void sigusr1_handler(vregs *r);
        static void sigsegv_invoc(int sig, void *arg, vregs *r);
        static void sigill_invoc(int sig, void *arg, vregs *r);
        void jump_to_rom(uint32 entry);

        void init_rom(void);
        void load_rom(void);

        int sheep_fd;                   // FD of sheep driver

        area_id kernel_area;    // Kernel Data area ID
        area_id kernel_area2;   // Alternate Kernel Data area ID
        area_id rom_area;               // ROM area ID
        area_id ram_area;               // RAM area ID
        area_id dr_cache_area;  // DR Cache area ID
        area_id dr_emulator_area;       // DR Emulator area ID

        struct sigaction sigusr1_action;        // Interrupt signal (of emulator thread)
        struct sigaction sigsegv_action;        // Data access exception signal (of emulator thread)
        struct sigaction sigill_action;         // Illegal instruction exception signal (of emulator thread)

        // Exceptions
        class area_error {};
        class file_open_error {};
        class file_read_error {};
        class rom_size_error {};
};


// Global variables
SheepShaver *the_app;   // Pointer to application object
#if !EMULATED_PPC
void *TOC;                              // TOC pointer
#endif
uint32 RAMBase;                 // Base address of Mac RAM
uint32 RAMSize;                 // Size of Mac RAM
uint32 KernelDataAddr;  // Address of Kernel Data
uint32 BootGlobsAddr;   // Address of BootGlobs structure at top of Mac RAM
uint32 DRCacheAddr;             // Address of DR Cache
uint32 DREmulatorAddr;  // Address of DR Emulator
uint32 PVR;                             // Theoretical PVR
int64 CPUClockSpeed;    // Processor clock speed (Hz)
int64 BusClockSpeed;    // Bus clock speed (Hz)
int64 TimebaseSpeed;    // Timebase clock speed (Hz)
system_info SysInfo;    // System information
uint8 *RAMBaseHost;             // Base address of Mac RAM (host address space)
uint8 *ROMBaseHost;             // Base address of Mac ROM (host address space)

static void *sig_stack = NULL;          // Stack for signal handlers
static void *extra_stack = NULL;        // Stack for SIGSEGV inside interrupt handler
uint32  SheepMem::page_size;            // Size of a native page
uintptr SheepMem::zero_page = 0;        // Address of ro page filled in with zeros
uintptr SheepMem::base;                         // Address of SheepShaver data
uintptr SheepMem::proc;                         // Bottom address of SheepShave procedures
uintptr SheepMem::data;                         // Top of SheepShaver data (stack like storage)
static area_id SheepMemArea;            // SheepShaver data area ID


// Prototypes
static void sigsegv_handler(vregs *r);
static void sigill_handler(vregs *r);


/*
 *  Create application object and start it
 */

int main(int argc, char **argv)
{       
        tzset();
        the_app = new SheepShaver();
        the_app->Run();
        delete the_app;
        return 0;
}


/*
 *  Run application
 */

#if !EMULATED_PPC
static asm void *get_toc(void)
{
        mr      r3,r2
        blr
}
#endif

void SheepShaver::ReadyToRun(void)
{
        // Print some info
        printf(GetString(STR_ABOUT_TEXT1), VERSION_MAJOR, VERSION_MINOR);
        printf(" %s\n", GetString(STR_ABOUT_TEXT2));

#if !EMULATED_PPC
        // Get TOC pointer
        TOC = get_toc();
#endif

        // Get system info
        get_system_info(&SysInfo);
        switch (SysInfo.cpu_type) {
                case B_CPU_PPC_601:
                        PVR = 0x00010000;
                        break;
                case B_CPU_PPC_603:
                        PVR = 0x00030000;
                        break;
                case B_CPU_PPC_603e:
                        PVR = 0x00060000;
                        break;
                case B_CPU_PPC_604:
                        PVR = 0x00040000;
                        break;
                case B_CPU_PPC_604e:
                        PVR = 0x00090000;
                        break;
                case B_CPU_PPC_750:
                        PVR = 0x00080000;
                        break;
                default:
                        PVR = 0x00040000;
                        break;
        }
        CPUClockSpeed = SysInfo.cpu_clock_speed;
        BusClockSpeed = SysInfo.bus_clock_speed;
        TimebaseSpeed = BusClockSpeed / 4;

        // Delete old areas
        area_id old_kernel_area = find_area(KERNEL_AREA_NAME);
        if (old_kernel_area > 0)
                delete_area(old_kernel_area);
        area_id old_kernel2_area = find_area(KERNEL_AREA2_NAME);
        if (old_kernel2_area > 0)
                delete_area(old_kernel2_area);
        area_id old_ram_area = find_area(RAM_AREA_NAME);
        if (old_ram_area > 0)
                delete_area(old_ram_area);
        area_id old_rom_area = find_area(ROM_AREA_NAME);
        if (old_rom_area > 0)
                delete_area(old_rom_area);
        area_id old_dr_cache_area = find_area(DR_CACHE_AREA_NAME);
        if (old_dr_cache_area > 0)
                delete_area(old_dr_cache_area);
        area_id old_dr_emulator_area = find_area(DR_EMULATOR_AREA_NAME);
        if (old_dr_emulator_area > 0)
                delete_area(old_dr_emulator_area);

        // Read preferences
        int argc = 0;
        char **argv = NULL;
        PrefsInit(argc, argv);

        // Init system routines
        SysInit();

        // Test amount of RAM available for areas
        if (SysInfo.max_pages * B_PAGE_SIZE < 16 * 1024 * 1024) {
                ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR));
                PostMessage(B_QUIT_REQUESTED);
                return;
        }

        // Show preferences editor (or start emulator directly)
        if (!PrefsFindBool("nogui"))
                PrefsEditor(MSG_START);
        else
                PostMessage(MSG_START);
}


/*
 *  Message received
 */

void SheepShaver::MessageReceived(BMessage *msg)
{
        switch (msg->what) {
                case MSG_START:
                        StartEmulator();
                        break;
                default:
                        BApplication::MessageReceived(msg);
        }
}


/*
 *  Start emulator
 */

void SheepShaver::StartEmulator(void)
{
        char str[256];

        // Open sheep driver and remap low memory
        sheep_fd = open("/dev/sheep", 0);
        if (sheep_fd < 0) {
                sprintf(str, GetString(STR_NO_SHEEP_DRIVER_ERR), strerror(sheep_fd), sheep_fd);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        status_t res = ioctl(sheep_fd, SHEEP_UP);
        if (res < 0) {
                sprintf(str, GetString(STR_SHEEP_UP_ERR), strerror(res), res);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }

        // Create areas for Kernel Data
        kernel_data = (KernelData *)KERNEL_DATA_BASE;
        kernel_area = create_area(KERNEL_AREA_NAME, &kernel_data, B_EXACT_ADDRESS, KERNEL_AREA_SIZE, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
        if (kernel_area < 0) {
                sprintf(str, GetString(STR_NO_KERNEL_DATA_ERR), strerror(kernel_area), kernel_area);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        emulator_data = &kernel_data->ed;
        KernelDataAddr = (uint32)kernel_data;
        D(bug("Kernel Data area %ld at %p, Emulator Data at %p\n", kernel_area, kernel_data, emulator_data));

        void *kernel_data2 = (void *)KERNEL_DATA2_BASE;
        kernel_area2 = clone_area(KERNEL_AREA2_NAME, &kernel_data2, B_EXACT_ADDRESS, B_READ_AREA | B_WRITE_AREA, kernel_area);
        if (kernel_area2 < 0) {
                sprintf(str, GetString(STR_NO_KERNEL_DATA_ERR), strerror(kernel_area2), kernel_area2);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        D(bug("Kernel Data 2 area %ld at %p\n", kernel_area2, kernel_data2));

        // Create area for SheepShaver data
        if (!SheepMem::Init()) {
                sprintf(str, GetString(STR_NO_SHEEP_MEM_AREA_ERR), strerror(SheepMemArea), SheepMemArea);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        
        // Create area for Mac RAM
        RAMSize = PrefsFindInt32("ramsize") & 0xfff00000;       // Round down to 1MB boundary
        if (RAMSize < 8*1024*1024) {
                WarningAlert(GetString(STR_SMALL_RAM_WARN));
                RAMSize = 8*1024*1024;
        }

        RAMBase = 0x10000000;
        ram_area = create_area(RAM_AREA_NAME, (void **)&RAMBase, B_BASE_ADDRESS, RAMSize, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
        if (ram_area < 0) {
                sprintf(str, GetString(STR_NO_RAM_AREA_ERR), strerror(ram_area), ram_area);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        RAMBaseHost = (uint8 *)RAMBase
        D(bug("RAM area %ld at %p\n", ram_area, RAMBaseHost));

        // Create area and load Mac ROM
        try {
                init_rom();
        } catch (area_error) {
                ErrorAlert(GetString(STR_NO_ROM_AREA_ERR));
                PostMessage(B_QUIT_REQUESTED);
                return;
        } catch (file_open_error) {
                ErrorAlert(GetString(STR_NO_ROM_FILE_ERR));
                PostMessage(B_QUIT_REQUESTED);
                return;
        } catch (file_read_error) {
                ErrorAlert(GetString(STR_ROM_FILE_READ_ERR));
                PostMessage(B_QUIT_REQUESTED);
                return;
        } catch (rom_size_error) {
                ErrorAlert(GetString(STR_ROM_SIZE_ERR));
                PostMessage(B_QUIT_REQUESTED);
                return;
        }

        // Create area for DR Cache
        DRCacheAddr = DR_CACHE_BASE;
        dr_cache_area = create_area(DR_CACHE_AREA_NAME, (void **)&DRCacheAddr, B_EXACT_ADDRESS, DR_CACHE_SIZE, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
        if (dr_cache_area < 0) {
                sprintf(str, GetString(STR_NO_KERNEL_DATA_ERR), strerror(dr_cache_area), dr_cache_area);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        D(bug("DR Cache area %ld at %p\n", dr_cache_area, DRCacheAddr));

        // Create area for DR Emulator
        DREmulatorAddr = DR_EMULATOR_BASE;
        dr_emulator_area = create_area(DR_EMULATOR_AREA_NAME, (void **)&DREmulatorAddr, B_EXACT_ADDRESS, DR_EMULATOR_SIZE, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
        if (dr_emulator_area < 0) {
                sprintf(str, GetString(STR_NO_KERNEL_DATA_ERR), strerror(dr_emulator_area), dr_emulator_area);
                ErrorAlert(str);
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        D(bug("DR Emulator area %ld at %p\n", dr_emulator_area, DREmulatorAddr));

        // Initialize everything
        if (!InitAll()) {
                PostMessage(B_QUIT_REQUESTED);
                return;
        }
        D(bug("Initialization complete\n"));

        // Clear caches (as we loaded and patched code) and write protect ROM
#if !EMULATED_PPC
        clear_caches(ROMBaseHost, ROM_AREA_SIZE, B_INVALIDATE_ICACHE | B_FLUSH_DCACHE);
#endif
        set_area_protection(rom_area, B_READ_AREA);

        // Initialize extra low memory
        D(bug("Initializing extra Low Memory...\n"));
        WriteMacInt32(XLM_SHEEP_OBJ, (uint32)this);                                             // Pointer to SheepShaver object
        D(bug("Extra Low Memory initialized\n"));

        // Disallow quitting with Alt-Q from now on
        AllowQuitting = false;

        // Start 60Hz interrupt
        tick_thread = spawn_thread(tick_func, "60Hz", B_URGENT_DISPLAY_PRIORITY, this);
        resume_thread(tick_thread);

        // Start NVRAM watchdog thread
        memcpy(last_xpram, XPRAM, XPRAM_SIZE);
        nvram_thread = spawn_thread(nvram_func, "NVRAM Watchdog", B_LOW_PRIORITY, this);
        resume_thread(nvram_thread);

        // Start emulator thread
        emul_thread = spawn_thread(emul_func, "MacOS", B_NORMAL_PRIORITY, this);
        resume_thread(emul_thread);
}


/*
 *  Quit requested
 */

bool SheepShaver::QuitRequested(void)
{
        if (AllowQuitting)
                return BApplication::QuitRequested();
        else
                return false;
}

void SheepShaver::Quit(void)
{
        status_t l;

        // Stop 60Hz interrupt
        if (tick_thread > 0) {
                TickThreadActive = false;
                wait_for_thread(tick_thread, &l);
        }

        // Stop NVRAM watchdog
        if (nvram_thread > 0) {
                status_t l;
                NVRAMThreadActive = false;
                suspend_thread(nvram_thread);   // Wake thread up from snooze()
                snooze(1000);
                resume_thread(nvram_thread);
                while (wait_for_thread(nvram_thread, &l) == B_INTERRUPTED) ;
        }

        // Wait for emulator thread to finish
        if (emul_thread > 0)
                wait_for_thread(emul_thread, &l);

        // Deinitialize everything
        ExitAll();

        // Delete SheepShaver globals
        SheepMem::Exit();

        // Delete DR Emulator area
        if (dr_emulator_area >= 0)
                delete_area(dr_emulator_area);

        // Delete DR Cache area
        if (dr_cache_area >= 0)
                delete_area(dr_cache_area);

        // Delete ROM area
        if (rom_area >= 0)
                delete_area(rom_area);

        // Delete RAM area
        if (ram_area >= 0)
                delete_area(ram_area);

        // Delete Kernel Data area2
        if (kernel_area2 >= 0)
                delete_area(kernel_area2);
        if (kernel_area >= 0)
                delete_area(kernel_area);

        // Unmap low memory and close sheep driver
        if (sheep_fd >= 0) {
                ioctl(sheep_fd, SHEEP_DOWN);
                close(sheep_fd);
        }

        // Exit system routines
        SysExit();

        // Exit preferences
        PrefsExit();

        BApplication::Quit();
}


/*
 *  Create area for ROM (sets rom_area) and load ROM file
 *
 *  area_error     : Cannot create area
 *  file_open_error: Cannot open ROM file
 *  file_read_error: Cannot read ROM file
 */

void SheepShaver::init_rom(void)
{
        // Size of a native page
        page_size = B_PAGE_SIZE;

        // Create area for ROM
        ROMBaseHost = (uint8 *)ROM_BASE;
        rom_area = create_area(ROM_AREA_NAME, (void **)&ROMBaseHost, B_EXACT_ADDRESS, ROM_AREA_SIZE, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
        if (rom_area < 0)
                throw area_error();
        D(bug("ROM area %ld at %p\n", rom_area, rom_addr));

        // Load ROM
        load_rom();
}


/*
 *  Load ROM file
 *
 *  file_open_error: Cannot open ROM file (nor use built-in ROM)
 *  file_read_error: Cannot read ROM file
 */

void SheepShaver::load_rom(void)
{
        // Get rom file path from preferences
        const char *rom_path = PrefsFindString("rom");

        // Try to open ROM file
        BFile file(rom_path ? rom_path : ROM_FILE_NAME, B_READ_ONLY);
        if (file.InitCheck() != B_NO_ERROR) {

                // Failed, then ask memory_mess driver for ROM
                uint8 *rom = new uint8[ROM_SIZE];       // Reading directly into the area doesn't work
                ssize_t actual = read(sheep_fd, (void *)rom, ROM_SIZE);
                if (actual == ROM_SIZE) {
                        memcpy((void *)ROM_BASE, rom, ROM_SIZE);
                        delete[] rom;
                        return;
                } else
                        throw file_open_error();
        }

        printf(GetString(STR_READING_ROM_FILE));

        // Get file size
        off_t rom_size = 0;
        file.GetSize(&rom_size);

        uint8 *rom = new uint8[ROM_SIZE];       // Reading directly into the area doesn't work
        ssize_t actual = file.Read((void *)rom, ROM_SIZE);
        
        // Decode Mac ROM
        if (!DecodeROM(rom, actual)) {
                if (rom_size != 4*1024*1024)
                        throw rom_size_error();
                else
                        throw file_read_error();
        }
        delete[] rom;
}


/*
 *  Emulator thread function
 */

status_t SheepShaver::emul_func(void *arg)
{
        SheepShaver *obj = (SheepShaver *)arg;

        // Install interrupt signal handler
        sigemptyset(&obj->sigusr1_action.sa_mask);
        obj->sigusr1_action.sa_handler = (__signal_func_ptr)(obj->sigusr1_invoc);
        obj->sigusr1_action.sa_flags = 0;
        obj->sigusr1_action.sa_userdata = arg;
        sigaction(SIGUSR1, &obj->sigusr1_action, NULL);

        // Install data access signal handler
        sigemptyset(&obj->sigsegv_action.sa_mask);
        obj->sigsegv_action.sa_handler = (__signal_func_ptr)(obj->sigsegv_invoc);
        obj->sigsegv_action.sa_flags = 0;
        obj->sigsegv_action.sa_userdata = arg;
        sigaction(SIGSEGV, &obj->sigsegv_action, NULL);

#if !EMULATED_PPC
        // Install illegal instruction signal handler
        sigemptyset(&obj->sigill_action.sa_mask);
        obj->sigill_action.sa_handler = (__signal_func_ptr)(obj->sigill_invoc);
        obj->sigill_action.sa_flags = 0;
        obj->sigill_action.sa_userdata = arg;
        sigaction(SIGILL, &obj->sigill_action, NULL);
#endif

        // Exceptions will send signals
        disable_debugger(true);

        // Install signal stack
        sig_stack = malloc(SIG_STACK_SIZE);
        extra_stack = malloc(SIG_STACK_SIZE);
        set_signal_stack(sig_stack, SIG_STACK_SIZE);

        // We're now ready to receive signals
        obj->ReadyForSignals = true;

        // Jump to ROM boot routine
        D(bug("Jumping to ROM\n"));
        obj->jump_to_rom(ROM_BASE + 0x310000);
        D(bug("Returned from ROM\n"));

        // We're no longer ready to receive signals
        obj->ReadyForSignals = false;
        obj->AllowQuitting = true;

        // Quit program
        be_app->PostMessage(B_QUIT_REQUESTED);
        return 0;
}


/*
 *  Jump into Mac ROM, start 680x0 emulator
 *  (also contains other EMUL_RETURN and EMUL_OP routines)
 */

#if EMULATED_PPC
extern void emul_ppc(uint32 start);
extern void init_emul_ppc(void);
void SheepShaver::jump_to_rom(uint32 entry)
{
        init_emul_ppc();
        emul_ppc(entry);
}
#else
asm void SheepShaver::jump_to_rom(register uint32 entry)
{
        // Create stack frame
        mflr    r0
        stw             r0,8(r1)
        mfcr    r0
        stw             r0,4(r1)
        stwu    r1,-(56+19*4+18*8)(r1)

        // Save PowerPC registers
        stmw    r13,56(r1)
        stfd    f14,56+19*4+0*8(r1)
        stfd    f15,56+19*4+1*8(r1)
        stfd    f16,56+19*4+2*8(r1)
        stfd    f17,56+19*4+3*8(r1)
        stfd    f18,56+19*4+4*8(r1)
        stfd    f19,56+19*4+5*8(r1)
        stfd    f20,56+19*4+6*8(r1)
        stfd    f21,56+19*4+7*8(r1)
        stfd    f22,56+19*4+8*8(r1)
        stfd    f23,56+19*4+9*8(r1)
        stfd    f24,56+19*4+10*8(r1)
        stfd    f25,56+19*4+11*8(r1)
        stfd    f26,56+19*4+12*8(r1)
        stfd    f27,56+19*4+13*8(r1)
        stfd    f28,56+19*4+14*8(r1)
        stfd    f29,56+19*4+15*8(r1)
        stfd    f30,56+19*4+16*8(r1)
        stfd    f31,56+19*4+17*8(r1)

        // Move entry address to ctr, get pointer to Emulator Data
        mtctr   r4
        lwz             r4,SheepShaver.emulator_data(r3)

        // Skip over EMUL_RETURN routine and get its address
        bl              @1


        /*
         *  EMUL_RETURN: Returned from emulator
         */

        // Restore PowerPC registers
        lwz             r1,XLM_EMUL_RETURN_STACK
        lwz             r2,XLM_TOC
        lmw             r13,56(r1)
        lfd             f14,56+19*4+0*8(r1)
        lfd             f15,56+19*4+1*8(r1)
        lfd             f16,56+19*4+2*8(r1)
        lfd             f17,56+19*4+3*8(r1)
        lfd             f18,56+19*4+4*8(r1)
        lfd             f19,56+19*4+5*8(r1)
        lfd             f20,56+19*4+6*8(r1)
        lfd             f21,56+19*4+7*8(r1)
        lfd             f22,56+19*4+8*8(r1)
        lfd             f23,56+19*4+9*8(r1)
        lfd             f24,56+19*4+10*8(r1)
        lfd             f25,56+19*4+11*8(r1)
        lfd             f26,56+19*4+12*8(r1)
        lfd             f27,56+19*4+13*8(r1)
        lfd             f28,56+19*4+14*8(r1)
        lfd             f29,56+19*4+15*8(r1)
        lfd             f30,56+19*4+16*8(r1)
        lfd             f31,56+19*4+17*8(r1)

        // Exiting from 68k emulator
        li              r0,1
        stw             r0,XLM_IRQ_NEST
        li              r0,MODE_NATIVE
        stw             r0,XLM_RUN_MODE

        // Return to caller of jump_to_rom()
        lwz             r0,56+19*4+18*8+8(r1)
        mtlr    r0
        lwz             r0,56+19*4+18*8+4(r1)
        mtcrf   0xff,r0
        addi    r1,r1,56+19*4+18*8
        blr


        // Save address of EMUL_RETURN routine for 68k emulator patch
@1      mflr    r0
        stw             r0,XLM_EMUL_RETURN_PROC

        // Skip over EXEC_RETURN routine and get its address
        bl              @2


        /*
         *  EXEC_RETURN: Returned from 68k routine executed with Execute68k()
         */

        // Save r25 (contains current 68k interrupt level)
        stw             r25,XLM_68K_R25

        // Reentering EMUL_OP mode
        li              r0,MODE_EMUL_OP
        stw             r0,XLM_RUN_MODE

        // Save 68k registers
        lwz             r4,56+19*4+18*8+12(r1)
        stw             r8,M68kRegisters.d[0](r4)
        stw             r9,M68kRegisters.d[1](r4)
        stw             r10,M68kRegisters.d[2](r4)
        stw             r11,M68kRegisters.d[3](r4)
        stw             r12,M68kRegisters.d[4](r4)
        stw             r13,M68kRegisters.d[5](r4)
        stw             r14,M68kRegisters.d[6](r4)
        stw             r15,M68kRegisters.d[7](r4)
        stw             r16,M68kRegisters.a[0](r4)
        stw             r17,M68kRegisters.a[1](r4)
        stw             r18,M68kRegisters.a[2](r4)
        stw             r19,M68kRegisters.a[3](r4)
        stw             r20,M68kRegisters.a[4](r4)
        stw             r21,M68kRegisters.a[5](r4)
        stw             r22,M68kRegisters.a[6](r4)

        // Restore PowerPC registers
        lmw             r13,56(r1)
#if SAVE_FP_EXEC_68K
        lfd             f14,56+19*4+0*8(r1)
        lfd             f15,56+19*4+1*8(r1)
        lfd             f16,56+19*4+2*8(r1)
        lfd             f17,56+19*4+3*8(r1)
        lfd             f18,56+19*4+4*8(r1)
        lfd             f19,56+19*4+5*8(r1)
        lfd             f20,56+19*4+6*8(r1)
        lfd             f21,56+19*4+7*8(r1)
        lfd             f22,56+19*4+8*8(r1)
        lfd             f23,56+19*4+9*8(r1)
        lfd             f24,56+19*4+10*8(r1)
        lfd             f25,56+19*4+11*8(r1)
        lfd             f26,56+19*4+12*8(r1)
        lfd             f27,56+19*4+13*8(r1)
        lfd             f28,56+19*4+14*8(r1)
        lfd             f29,56+19*4+15*8(r1)
        lfd             f30,56+19*4+16*8(r1)
        lfd             f31,56+19*4+17*8(r1)
#endif

        // Return to caller
        lwz             r0,56+19*4+18*8+8(r1)
        mtlr    r0
        addi    r1,r1,56+19*4+18*8
        blr


        // Stave address of EXEC_RETURN routine for 68k emulator patch
@2      mflr    r0
        stw             r0,XLM_EXEC_RETURN_PROC

        // Skip over EMUL_BREAK/EMUL_OP routine and get its address
        bl              @3


        /*
         *  EMUL_BREAK/EMUL_OP: Execute native routine, selector in r5 (my own private mode switch)
         *
         *  68k registers are stored in a M68kRegisters struct on the stack
         *  which the native routine may read and modify
         */

        // Save r25 (contains current 68k interrupt level)
        stw             r25,XLM_68K_R25

        // Entering EMUL_OP mode within 68k emulator
        li              r0,MODE_EMUL_OP
        stw             r0,XLM_RUN_MODE

        // Create PowerPC stack frame, reserve space for M68kRegisters
        mr              r3,r1
        subi    r1,r1,56                // Fake "caller" frame
        rlwinm  r1,r1,0,0,29    // Align stack

        mfcr    r0
        rlwinm  r0,r0,0,11,8
        stw             r0,4(r1)
        mfxer   r0
        stw             r0,16(r1)
        stw             r2,12(r1)
        stwu    r1,-(56+16*4+15*8)(r1)
        lwz             r2,XLM_TOC

        // Save 68k registers
        stw             r8,56+M68kRegisters.d[0](r1)
        stw             r9,56+M68kRegisters.d[1](r1)
        stw             r10,56+M68kRegisters.d[2](r1)
        stw             r11,56+M68kRegisters.d[3](r1)
        stw             r12,56+M68kRegisters.d[4](r1)
        stw             r13,56+M68kRegisters.d[5](r1)
        stw             r14,56+M68kRegisters.d[6](r1)
        stw             r15,56+M68kRegisters.d[7](r1)
        stw             r16,56+M68kRegisters.a[0](r1)
        stw             r17,56+M68kRegisters.a[1](r1)
        stw             r18,56+M68kRegisters.a[2](r1)
        stw             r19,56+M68kRegisters.a[3](r1)
        stw             r20,56+M68kRegisters.a[4](r1)
        stw             r21,56+M68kRegisters.a[5](r1)
        stw             r22,56+M68kRegisters.a[6](r1)
        stw             r3,56+M68kRegisters.a[7](r1)
        stfd    f0,56+16*4+0*8(r1)
        stfd    f1,56+16*4+1*8(r1)
        stfd    f2,56+16*4+2*8(r1)
        stfd    f3,56+16*4+3*8(r1)
        stfd    f4,56+16*4+4*8(r1)
        stfd    f5,56+16*4+5*8(r1)
        stfd    f6,56+16*4+6*8(r1)
        stfd    f7,56+16*4+7*8(r1)
        mffs    f0
        stfd    f8,56+16*4+8*8(r1)
        stfd    f9,56+16*4+9*8(r1)
        stfd    f10,56+16*4+10*8(r1)
        stfd    f11,56+16*4+11*8(r1)
        stfd    f12,56+16*4+12*8(r1)
        stfd    f13,56+16*4+13*8(r1)
        stfd    f0,56+16*4+14*8(r1)

        // Execute native routine
        addi    r3,r1,56
        mr              r4,r24
        bl              EmulOp

        // Restore 68k registers
        lwz             r8,56+M68kRegisters.d[0](r1)
        lwz             r9,56+M68kRegisters.d[1](r1)
        lwz             r10,56+M68kRegisters.d[2](r1)
        lwz             r11,56+M68kRegisters.d[3](r1)
        lwz             r12,56+M68kRegisters.d[4](r1)
        lwz             r13,56+M68kRegisters.d[5](r1)
        lwz             r14,56+M68kRegisters.d[6](r1)
        lwz             r15,56+M68kRegisters.d[7](r1)
        lwz             r16,56+M68kRegisters.a[0](r1)
        lwz             r17,56+M68kRegisters.a[1](r1)
        lwz             r18,56+M68kRegisters.a[2](r1)
        lwz             r19,56+M68kRegisters.a[3](r1)
        lwz             r20,56+M68kRegisters.a[4](r1)
        lwz             r21,56+M68kRegisters.a[5](r1)
        lwz             r22,56+M68kRegisters.a[6](r1)
        lwz             r3,56+M68kRegisters.a[7](r1)
        lfd             f13,56+16*4+14*8(r1)
        lfd             f0,56+16*4+0*8(r1)
        lfd             f1,56+16*4+1*8(r1)
        lfd             f2,56+16*4+2*8(r1)
        lfd             f3,56+16*4+3*8(r1)
        lfd             f4,56+16*4+4*8(r1)
        lfd             f5,56+16*4+5*8(r1)
        lfd             f6,56+16*4+6*8(r1)
        lfd             f7,56+16*4+7*8(r1)
        mtfsf   0xff,f13
        lfd             f8,56+16*4+8*8(r1)
        lfd             f9,56+16*4+9*8(r1)
        lfd             f10,56+16*4+10*8(r1)
        lfd             f11,56+16*4+11*8(r1)
        lfd             f12,56+16*4+12*8(r1)
        lfd             f13,56+16*4+13*8(r1)

        // Delete PowerPC stack frame
        lwz             r2,56+16*4+15*8+12(r1)
        lwz             r0,56+16*4+15*8+16(r1)
        mtxer   r0
        lwz             r0,56+16*4+15*8+4(r1)
        mtcrf   0xff,r0
        mr              r1,r3

        // Reeintering 68k emulator
        li              r0,MODE_68K
        stw             r0,XLM_RUN_MODE

        // Set r0 to 0 for 68k emulator
        li              r0,0

        // Execute next 68k opcode
        rlwimi  r29,r27,3,13,28
        lhau    r27,2(r24)
        mtlr    r29
        blr


        // Save address of EMUL_BREAK/EMUL_OP routine for 68k emulator patch
@3      mflr    r0
        stw             r0,XLM_EMUL_OP_PROC

        // Save stack pointer for EMUL_RETURN
        stw             r1,XLM_EMUL_RETURN_STACK

        // Preset registers for ROM boot routine
        lis             r3,0x40b0               // Pointer to ROM boot structure
        ori             r3,r3,0xd000

        // 68k emulator is now active
        li              r0,MODE_68K
        stw             r0,XLM_RUN_MODE

        // Jump to ROM
        bctr
}
#endif


#if !EMULATED_PPC
/*
 *  Execute 68k subroutine (must be ended with RTS)
 *  This must only be called by the emul_thread when in EMUL_OP mode
 *  r->a[7] is unused, the routine runs on the caller's stack
 */

#if SAFE_EXEC_68K
void execute_68k(uint32 pc, M68kRegisters *r);

void Execute68k(uint32 pc, M68kRegisters *r)
{
        if (*(uint32 *)XLM_RUN_MODE != MODE_EMUL_OP)
                printf("FATAL: Execute68k() not called from EMUL_OP mode\n");
        if (find_thread(NULL) != the_app->emul_thread)
                printf("FATAL: Execute68k() not called from emul_thread\n");
        execute_68k(pc, r);
}

asm void execute_68k(register uint32 pc, register M68kRegisters *r)
#else
asm void Execute68k(register uint32 pc, register M68kRegisters *r)
#endif
{
        // Create stack frame
        mflr    r0
        stw             r0,8(r1)
        stw             r4,12(r1)
        stwu    r1,-(56+19*4+18*8)(r1)

        // Save PowerPC registers
        stmw    r13,56(r1)
#if SAVE_FP_EXEC_68K
        stfd    f14,56+19*4+0*8(r1)
        stfd    f15,56+19*4+1*8(r1)
        stfd    f16,56+19*4+2*8(r1)
        stfd    f17,56+19*4+3*8(r1)
        stfd    f18,56+19*4+4*8(r1)
        stfd    f19,56+19*4+5*8(r1)
        stfd    f20,56+19*4+6*8(r1)
        stfd    f21,56+19*4+7*8(r1)
        stfd    f22,56+19*4+8*8(r1)
        stfd    f23,56+19*4+9*8(r1)
        stfd    f24,56+19*4+10*8(r1)
        stfd    f25,56+19*4+11*8(r1)
        stfd    f26,56+19*4+12*8(r1)
        stfd    f27,56+19*4+13*8(r1)
        stfd    f28,56+19*4+14*8(r1)
        stfd    f29,56+19*4+15*8(r1)
        stfd    f30,56+19*4+16*8(r1)
        stfd    f31,56+19*4+17*8(r1)
#endif

        // Set up registers for 68k emulator
        lwz             r31,XLM_KERNEL_DATA     // Pointer to Kernel Data
        addi    r31,r31,0x1000
        li              r0,0
        mtcrf   0xff,r0
        creqv   11,11,11                        // Supervisor mode
        lwz             r8,M68kRegisters.d[0](r4)
        lwz             r9,M68kRegisters.d[1](r4)
        lwz             r10,M68kRegisters.d[2](r4)
        lwz             r11,M68kRegisters.d[3](r4)
        lwz             r12,M68kRegisters.d[4](r4)
        lwz             r13,M68kRegisters.d[5](r4)
        lwz             r14,M68kRegisters.d[6](r4)
        lwz             r15,M68kRegisters.d[7](r4)
        lwz             r16,M68kRegisters.a[0](r4)
        lwz             r17,M68kRegisters.a[1](r4)
        lwz             r18,M68kRegisters.a[2](r4)
        lwz             r19,M68kRegisters.a[3](r4)
        lwz             r20,M68kRegisters.a[4](r4)
        lwz             r21,M68kRegisters.a[5](r4)
        lwz             r22,M68kRegisters.a[6](r4)
        li              r23,0
        mr              r24,r3
        lwz             r25,XLM_68K_R25         // MSB of SR
        li              r26,0
        li              r28,0                           // VBR
        lwz             r29,0x74(r31)           // Pointer to opcode table
        lwz             r30,0x78(r31)           // Address of emulator

        // Push return address (points to EXEC_RETURN opcode) on stack
        li              r0,XLM_EXEC_RETURN_OPCODE
        stwu    r0,-4(r1)

        // Reentering 68k emulator
        li              r0,MODE_68K
        stw             r0,XLM_RUN_MODE

        // Set r0 to 0 for 68k emulator
        li              r0,0

        // Execute 68k opcode
        lha             r27,0(r24)
        rlwimi  r29,r27,3,13,28
        lhau    r27,2(r24)
        mtlr    r29
        blr
}


/*
 *  Execute 68k A-Trap from EMUL_OP routine
 *  r->a[7] is unused, the routine runs on the caller's stack
 */

void Execute68kTrap(uint16 trap, M68kRegisters *r)
{
        uint16 proc[2] = {trap, M68K_RTS};
        Execute68k((uint32)proc, r);
}


/*
 *  Quit emulator (must only be called from main thread)
 */

asm void QuitEmulator(void)
{
        lwz             r0,XLM_EMUL_RETURN_PROC
        mtlr    r0
        blr
}
#endif


/*
 *  Dump 68k registers
 */

void Dump68kRegs(M68kRegisters *r)
{
        // Display 68k registers
        for (int i=0; i<8; i++) {
                printf("d%d: %08lx", i, r->d[i]);
                if (i == 3 || i == 7)
                        printf("\n");
                else
                        printf(", ");
        }
        for (int i=0; i<8; i++) {
                printf("a%d: %08lx", i, r->a[i]);
                if (i == 3 || i == 7)
                        printf("\n");
                else
                        printf(", ");
        }
}


/*
 *  Make code executable
 */

void MakeExecutable(int dummy, uint32 start, uint32 length)
{
        if ((start >= ROM_BASE) && (start < (ROM_BASE + ROM_SIZE)))
                return;
        clear_caches((void *)start, length, B_INVALIDATE_ICACHE | B_FLUSH_DCACHE);
}


/*
 *  NVRAM watchdog thread (saves NVRAM every minute)
 */

status_t SheepShaver::nvram_func(void *arg)
{
        SheepShaver *obj = (SheepShaver *)arg;

        while (obj->NVRAMThreadActive) {
                snooze(60*1000000);
                if (memcmp(obj->last_xpram, XPRAM, XPRAM_SIZE)) {
                        memcpy(obj->last_xpram, XPRAM, XPRAM_SIZE);
                        SaveXPRAM();
                }
        }
        return 0;
}


/*
 *  60Hz thread (really 60.15Hz)
 */

status_t SheepShaver::tick_func(void *arg)
{
        SheepShaver *obj = (SheepShaver *)arg;
        int tick_counter = 0;
        bigtime_t current = system_time();

        while (obj->TickThreadActive) {

                // Wait
                current += 16625;
                snooze_until(current, B_SYSTEM_TIMEBASE);

                // Pseudo Mac 1Hz interrupt, update local time
                if (++tick_counter > 60) {
                        tick_counter = 0;
                        WriteMacInt32(0x20c, TimerDateTime());
                }

                // 60Hz interrupt
                if (ReadMacInt32(XLM_IRQ_NEST) == 0) {
                        SetInterruptFlag(INTFLAG_VIA);
                        TriggerInterrupt();
                }
        }
        return 0;
}


/*
 *  Trigger signal USR1 from another thread
 */

void TriggerInterrupt(void)
{
#if 0
        WriteMacInt32(0x16a, ReadMacInt32(0x16a) + 1);
#else
        if (the_app->emul_thread > 0 && the_app->ReadyForSignals)
                send_signal(the_app->emul_thread, SIGUSR1);
#endif
}


/*
 *  Mutexes
 */

struct B2_mutex {
        int dummy;      //!!
};

B2_mutex *B2_create_mutex(void)
{
        return new B2_mutex;
}

void B2_lock_mutex(B2_mutex *mutex)
{
}

void B2_unlock_mutex(B2_mutex *mutex)
{
}

void B2_delete_mutex(B2_mutex *mutex)
{
        delete mutex;
}


/*
 *  Set/clear interrupt flags (must be done atomically!)
 */

volatile uint32 InterruptFlags = 0;

void SetInterruptFlag(uint32 flag)
{
        atomic_or((int32 *)&InterruptFlags, flag);
}

void ClearInterruptFlag(uint32 flag)
{
        atomic_and((int32 *)&InterruptFlags, ~flag);
}


/*
 *  Disable interrupts
 */

void DisableInterrupt(void)
{
        atomic_add((int32 *)XLM_IRQ_NEST, 1);
}


/*
 *  Enable interrupts
 */

void EnableInterrupt(void)
{
        atomic_add((int32 *)XLM_IRQ_NEST, -1);
}


/*
 *  USR1 handler
 */

void SheepShaver::sigusr1_invoc(int sig, void *arg, vregs *r)
{
        ((SheepShaver *)arg)->sigusr1_handler(r);
}

#if !EMULATED_PPC
static asm void ppc_interrupt(register uint32 entry)
{
        fralloc

        // Get address of return routine
        bl              @1

        // Return routine
        frfree
        blr

@1
        // Prepare registers for nanokernel interrupt routine
        mtctr   r1
        lwz             r1,XLM_KERNEL_DATA
        stw             r6,0x018(r1)
        mfctr   r6
        stw             r6,0x004(r1)
        lwz             r6,0x65c(r1)
        stw             r7,0x13c(r6)
        stw             r8,0x144(r6)
        stw             r9,0x14c(r6)
        stw             r10,0x154(r6)
        stw             r11,0x15c(r6)
        stw             r12,0x164(r6)
        stw             r13,0x16c(r6)

        mflr    r10
        mfcr    r13
        lwz             r7,0x660(r1)
        mflr    r12
        rlwimi. r7,r7,8,0,0
        li              r11,0
        ori             r11,r11,0xf072  // MSR (SRR1)
        mtcrf   0x70,r11
        li              r8,0

        // Enter nanokernel
        mtlr    r3
        blr
}
#endif

void SheepShaver::sigusr1_handler(vregs *r)
{
        // Do nothing if interrupts are disabled
        if ((*(int32 *)XLM_IRQ_NEST) > 0)
                return;

        // Interrupt action depends on current run mode
        switch (*(uint32 *)XLM_RUN_MODE) {
                case MODE_68K:
                        // 68k emulator active, trigger 68k interrupt level 1
                        *(uint16 *)(kernel_data->v[0x67c >> 2]) = 1;
                        r->cr |= kernel_data->v[0x674 >> 2];
                        break;

#if INTERRUPTS_IN_NATIVE_MODE
                case MODE_NATIVE:
                        // 68k emulator inactive, in nanokernel?
                        if (r->r1 != KernelDataAddr) {
                                // No, prepare for 68k interrupt level 1
                                *(uint16 *)(kernel_data->v[0x67c >> 2]) = 1;
                                *(uint32 *)(kernel_data->v[0x658 >> 2] + 0xdc) |= kernel_data->v[0x674 >> 2];

                                // Execute nanokernel interrupt routine (this will activate the 68k emulator)
                                atomic_add((int32 *)XLM_IRQ_NEST, 1);
                                if (ROMType == ROMTYPE_NEWWORLD)
                                        ppc_interrupt(ROM_BASE + 0x312b1c);
                                else
                                        ppc_interrupt(ROM_BASE + 0x312a3c);
                        }
                        break;
#endif

#if INTERRUPTS_IN_EMUL_OP_MODE
                case MODE_EMUL_OP:
                        // 68k emulator active, within EMUL_OP routine, execute 68k interrupt routine directly when interrupt level is 0
                        if ((*(uint32 *)XLM_68K_R25 & 7) == 0) {

                                // Set extra stack for SIGSEGV handler
                                set_signal_stack(extra_stack, SIG_STACK_SIZE);
#if 1
                                // Execute full 68k interrupt routine
                                M68kRegisters r;
                                uint32 old_r25 = *(uint32 *)XLM_68K_R25;        // Save interrupt level
                                *(uint32 *)XLM_68K_R25 = 0x21;                          // Execute with interrupt level 1
                                static const uint16 proc[] = {
                                        0x3f3c, 0x0000,         // move.w       #$0000,-(sp)    (fake format word)
                                        0x487a, 0x000a,         // pea          @1(pc)                  (return address)
                                        0x40e7,                         // move         sr,-(sp)                (saved SR)
                                        0x2078, 0x0064,         // move.l       $64,a0
                                        0x4ed0,                         // jmp          (a0)
                                        M68K_RTS                        // @1
                                };
                                Execute68k((uint32)proc, &r);
                                *(uint32 *)XLM_68K_R25 = old_r25;                       // Restore interrupt level
#else
                                // Only update cursor
                                if (HasMacStarted()) {
                                        if (InterruptFlags & INTFLAG_VIA) {
                                                ClearInterruptFlag(INTFLAG_VIA);
                                                ADBInterrupt();
                                                ExecuteNative(NATIVE_VIDEO_VBL);
                                        }
                                }
#endif
                                // Reset normal signal stack
                                set_signal_stack(sig_stack, SIG_STACK_SIZE);
                        }
                        break;
#endif
        }
}


/*
 *  SIGSEGV handler
 */

static uint32 segv_r[32];

#if !EMULATED_PPC
asm void SheepShaver::sigsegv_invoc(register int sig, register void *arg, register vregs *r)
{
        mflr    r0
        stw             r0,8(r1)
        stwu    r1,-56(r1)

        lwz             r3,segv_r(r2)
        stmw    r13,13*4(r3)

        mr              r3,r5
        bl              sigsegv_handler

        lwz             r3,segv_r(r2)
        lmw             r13,13*4(r3)

        lwz             r0,56+8(r1)
        mtlr    r0
        addi    r1,r1,56
        blr
}
#endif

static void sigsegv_handler(vregs *r)
{
        char str[256];

        // Fetch volatile registers
        segv_r[0] = r->r0;
        segv_r[1] = r->r1;
        segv_r[2] = r->r2;
        segv_r[3] = r->r3;
        segv_r[4] = r->r4;
        segv_r[5] = r->r5;
        segv_r[6] = r->r6;
        segv_r[7] = r->r7;
        segv_r[8] = r->r8;
        segv_r[9] = r->r9;
        segv_r[10] = r->r10;
        segv_r[11] = r->r11;
        segv_r[12] = r->r12;

        // Get opcode and divide into fields
        uint32 opcode = *(uint32 *)r->pc;
        uint32 primop = opcode >> 26;
        uint32 exop = (opcode >> 1) & 0x3ff;
        uint32 ra = (opcode >> 16) & 0x1f;
        uint32 rb = (opcode >> 11) & 0x1f;
        uint32 rd = (opcode >> 21) & 0x1f;
        uint32 imm = opcode & 0xffff;

        // Fault in Mac ROM or RAM?
        bool mac_fault = (r->pc >= ROM_BASE) && (r->pc < (ROM_BASE + ROM_AREA_SIZE)) || (r->pc >= RAMBase) && (r->pc < (RAMBase + RAMSize));
        if (mac_fault) {

                // "VM settings" during MacOS 8 installation
                if (r->pc == ROM_BASE + 0x488160 && segv_r[20] == 0xf8000000) {
                        r->pc += 4;
                        segv_r[8] = 0;
                        goto rti;

                // MacOS 8.5 installation
                } else if (r->pc == ROM_BASE + 0x488140 && segv_r[16] == 0xf8000000) {
                        r->pc += 4;
                        segv_r[8] = 0;
                        goto rti;

                // MacOS 8 serial drivers on startup
                } else if (r->pc == ROM_BASE + 0x48e080 && (segv_r[8] == 0xf3012002 || segv_r[8] == 0xf3012000)) {
                        r->pc += 4;
                        segv_r[8] = 0;
                        goto rti;

                // MacOS 8.1 serial drivers on startup
                } else if (r->pc == ROM_BASE + 0x48c5e0 && (segv_r[20] == 0xf3012002 || segv_r[20] == 0xf3012000)) {
                        r->pc += 4;
                        goto rti;
                } else if (r->pc == ROM_BASE + 0x4a10a0 && (segv_r[20] == 0xf3012002 || segv_r[20] == 0xf3012000)) {
                        r->pc += 4;
                        goto rti;
                }
        }

        // Analyze opcode
        enum {
                TYPE_UNKNOWN,
                TYPE_LOAD,
                TYPE_STORE
        } transfer_type = TYPE_UNKNOWN;
        enum {
                SIZE_UNKNOWN,
                SIZE_BYTE,
                SIZE_HALFWORD,
                SIZE_WORD
        } transfer_size = SIZE_UNKNOWN;
        enum {
                MODE_UNKNOWN,
                MODE_NORM,
                MODE_U,
                MODE_X,
                MODE_UX
        } addr_mode = MODE_UNKNOWN;
        switch (primop) {
                case 31:
                        switch (exop) {
                                case 23:        // lwzx
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
                                case 55:        // lwzux
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
                                case 87:        // lbzx
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
                                case 119:       // lbzux
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
                                case 151:       // stwx
                                        transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
                                case 183:       // stwux
                                        transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
                                case 215:       // stbx
                                        transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
                                case 247:       // stbux
                                        transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
                                case 279:       // lhzx
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
                                case 311:       // lhzux
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
                                case 343:       // lhax
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
                                case 375:       // lhaux
                                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
                                case 407:       // sthx
                                        transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
                                case 439:       // sthux
                                        transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
                        }
                        break;

                case 32:        // lwz
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
                case 33:        // lwzu
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
                case 34:        // lbz
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
                case 35:        // lbzu
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
                case 36:        // stw
                        transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
                case 37:        // stwu
                        transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
                case 38:        // stb
                        transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
                case 39:        // stbu
                        transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
                case 40:        // lhz
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
                case 41:        // lhzu
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
                case 42:        // lha
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
                case 43:        // lhau
                        transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
                case 44:        // sth
                        transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
                case 45:        // sthu
                        transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
        }

        // Calculate effective address
        uint32 addr = 0;
        switch (addr_mode) {
                case MODE_X:
                case MODE_UX:
                        if (ra == 0)
                                addr = segv_r[rb];
                        else
                                addr = segv_r[ra] + segv_r[rb];
                        break;
                case MODE_NORM:
                case MODE_U:
                        if (ra == 0)
                                addr = (int32)(int16)imm;
                        else
                                addr = segv_r[ra] + (int32)(int16)imm;
                        break;
                default:
                        break;
        }

        // Ignore ROM writes
        if (transfer_type == TYPE_STORE && addr >= ROM_BASE && addr < ROM_BASE + ROM_SIZE) {
                D(bug("WARNING: %s write access to ROM at %p, pc %p\n", transfer_size == SIZE_BYTE ? "Byte" : transfer_size == SIZE_HALFWORD ? "Halfword" : "Word", addr, r->pc));
                if (addr_mode == MODE_U || addr_mode == MODE_UX)
                        segv_r[ra] = addr;
                r->pc += 4;
                goto rti;
        }

        // Fault in Mac ROM or RAM?
        if (mac_fault) {

                // Ignore illegal memory accesses?
                if (PrefsFindBool("ignoresegv")) {
                        if (addr_mode == MODE_U || addr_mode == MODE_UX)
                                segv_r[ra] = addr;
                        if (transfer_type == TYPE_LOAD)
                                segv_r[rd] = 0;
                        r->pc += 4;
                        goto rti;
                }

                // In GUI mode, show error alert
                if (!PrefsFindBool("nogui")) {
                        if (transfer_type == TYPE_LOAD || transfer_type == TYPE_STORE)
                                sprintf(str, GetString(STR_MEM_ACCESS_ERR), transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_HALFWORD ? "halfword" : "word", transfer_type == TYPE_LOAD ? GetString(STR_MEM_ACCESS_READ) : GetString(STR_MEM_ACCESS_WRITE), addr, r->pc, segv_r[24], segv_r[1]);
                        else
                                sprintf(str, GetString(STR_UNKNOWN_SEGV_ERR), r->pc, segv_r[24], segv_r[1], opcode);
                        ErrorAlert(str);
                        QuitEmulator();
                        return;
                }
        }

        // For all other errors, jump into debugger
        sprintf(str, "SIGSEGV\n"
                "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                "  xer %08lx     cr %08lx  fpscr %08lx\n"
                "   r0 %08lx     r1 %08lx     r2 %08lx     r3 %08lx\n"
                "   r4 %08lx     r5 %08lx     r6 %08lx     r7 %08lx\n"
                "   r8 %08lx     r9 %08lx    r10 %08lx    r11 %08lx\n"
                "  r12 %08lx    r13 %08lx    r14 %08lx    r15 %08lx\n"
                "  r16 %08lx    r17 %08lx    r18 %08lx    r19 %08lx\n"
                "  r20 %08lx    r21 %08lx    r22 %08lx    r23 %08lx\n"
                "  r24 %08lx    r25 %08lx    r26 %08lx    r27 %08lx\n"
                "  r28 %08lx    r29 %08lx    r30 %08lx    r31 %08lx\n",
                r->pc, r->lr, r->ctr, r->msr,
                r->xer, r->cr, r->fpscr,
                r->r0, r->r1, r->r2, r->r3,
                r->r4, r->r5, r->r6, r->r7,
                r->r8, r->r9, r->r10, r->r11,
                r->r12, segv_r[13], segv_r[14], segv_r[15],
                segv_r[16], segv_r[17], segv_r[18], segv_r[19],
                segv_r[20], segv_r[21], segv_r[22], segv_r[23],
                segv_r[24], segv_r[25], segv_r[26], segv_r[27],
                segv_r[28], segv_r[29], segv_r[30], segv_r[31]);
        VideoQuitFullScreen();
        disable_debugger(false);
        debugger(str);
        exit(1);
        return;

rti:
        // Restore volatile registers
        r->r0 = segv_r[0];
        r->r1 = segv_r[1];
        r->r2 = segv_r[2];
        r->r3 = segv_r[3];
        r->r4 = segv_r[4];
        r->r5 = segv_r[5];
        r->r6 = segv_r[6];
        r->r7 = segv_r[7];
        r->r8 = segv_r[8];
        r->r9 = segv_r[9];
        r->r10 = segv_r[10];
        r->r11 = segv_r[11];
        r->r12 = segv_r[12];
}


/*
 *  SIGILL handler
 */

#if !EMULATED_PPC
asm void SheepShaver::sigill_invoc(register int sig, register void *arg, register vregs *r)
{
        mflr    r0
        stw             r0,8(r1)
        stwu    r1,-56(r1)

        lwz             r3,segv_r(r2)
        stmw    r13,13*4(r3)

        mr              r3,r5
        bl              sigill_handler

        lwz             r3,segv_r(r2)
        lmw             r13,13*4(r3)

        lwz             r0,56+8(r1)
        mtlr    r0
        addi    r1,r1,56
        blr
}
#endif

static void sigill_handler(vregs *r)
{
        char str[256];

        // Fetch volatile registers
        segv_r[0] = r->r0;
        segv_r[1] = r->r1;
        segv_r[2] = r->r2;
        segv_r[3] = r->r3;
        segv_r[4] = r->r4;
        segv_r[5] = r->r5;
        segv_r[6] = r->r6;
        segv_r[7] = r->r7;
        segv_r[8] = r->r8;
        segv_r[9] = r->r9;
        segv_r[10] = r->r10;
        segv_r[11] = r->r11;
        segv_r[12] = r->r12;

        // Get opcode and divide into fields
        uint32 opcode = *(uint32 *)r->pc;
        uint32 primop = opcode >> 26;
        uint32 exop = (opcode >> 1) & 0x3ff;
        uint32 ra = (opcode >> 16) & 0x1f;
        uint32 rb = (opcode >> 11) & 0x1f;
        uint32 rd = (opcode >> 21) & 0x1f;
        uint32 imm = opcode & 0xffff;

        // Fault in Mac ROM or RAM?
        bool mac_fault = (r->pc >= ROM_BASE) && (r->pc < (ROM_BASE + ROM_AREA_SIZE)) || (r->pc >= RAMBase) && (r->pc < (RAMBase + RAMSize));
        if (mac_fault) {

                switch (primop) {
                        case 9:         // POWER instructions
                        case 22:
power_inst:             sprintf(str, GetString(STR_POWER_INSTRUCTION_ERR), r->pc, segv_r[1], opcode);
                                ErrorAlert(str);
                                QuitEmulator();
                                return;

                        case 31:
                                switch (exop) {
                                        case 83:        // mfmsr
                                                segv_r[rd] = 0xf072;
                                                r->pc += 4;
                                                goto rti;

                                        case 210:       // mtsr
                                        case 242:       // mtsrin
                                        case 306:       // tlbie
                                                r->pc += 4;
                                                goto rti;

                                        case 339: {     // mfspr
                                                int spr = ra | (rb << 5);
                                                switch (spr) {
                                                        case 0:         // MQ
                                                        case 22:        // DEC
                                                        case 952:       // MMCR0
                                                        case 953:       // PMC1
                                                        case 954:       // PMC2
                                                        case 955:       // SIA
                                                        case 956:       // MMCR1
                                                        case 957:       // PMC3
                                                        case 958:       // PMC4
                                                        case 959:       // SDA
                                                                r->pc += 4;
                                                                goto rti;
                                                        case 25:        // SDR1
                                                                segv_r[rd] = 0xdead001f;
                                                                r->pc += 4;
                                                                goto rti;
                                                        case 287:       // PVR
                                                                segv_r[rd] = PVR;
                                                                r->pc += 4;
                                                                goto rti;
                                                }
                                                break;
                                        }

                                        case 467: {     // mtspr
                                                int spr = ra | (rb << 5);
                                                switch (spr) {
                                                        case 0:         // MQ
                                                        case 22:        // DEC
                                                        case 275:       // SPRG3
                                                        case 528:       // IBAT0U
                                                        case 529:       // IBAT0L
                                                        case 530:       // IBAT1U
                                                        case 531:       // IBAT1L
                                                        case 532:       // IBAT2U
                                                        case 533:       // IBAT2L
                                                        case 534:       // IBAT3U
                                                        case 535:       // IBAT3L
                                                        case 536:       // DBAT0U
                                                        case 537:       // DBAT0L
                                                        case 538:       // DBAT1U
                                                        case 539:       // DBAT1L
                                                        case 540:       // DBAT2U
                                                        case 541:       // DBAT2L
                                                        case 542:       // DBAT3U
                                                        case 543:       // DBAT3L
                                                        case 952:       // MMCR0
                                                        case 953:       // PMC1
                                                        case 954:       // PMC2
                                                        case 955:       // SIA
                                                        case 956:       // MMCR1
                                                        case 957:       // PMC3
                                                        case 958:       // PMC4
                                                        case 959:       // SDA
                                                                r->pc += 4;
                                                                goto rti;
                                                }
                                                break;
                                        }

                                        case 29: case 107: case 152: case 153:  // POWER instructions
                                        case 184: case 216: case 217: case 248:
                                        case 264: case 277: case 331: case 360:
                                        case 363: case 488: case 531: case 537:
                                        case 541: case 664: case 665: case 696:
                                        case 728: case 729: case 760: case 920:
                                        case 921: case 952:
                                                goto power_inst;
                                }
                }

                // In GUI mode, show error alert
                if (!PrefsFindBool("nogui")) {
                        sprintf(str, GetString(STR_UNKNOWN_SEGV_ERR), r->pc, segv_r[24], segv_r[1], opcode);
                        ErrorAlert(str);
                        QuitEmulator();
                        return;
                }
        }

        // For all other errors, jump into debugger
        sprintf(str, "SIGILL\n"
                "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                "  xer %08lx     cr %08lx  fpscr %08lx\n"
                "   r0 %08lx     r1 %08lx     r2 %08lx     r3 %08lx\n"
                "   r4 %08lx     r5 %08lx     r6 %08lx     r7 %08lx\n"
                "   r8 %08lx     r9 %08lx    r10 %08lx    r11 %08lx\n"
                "  r12 %08lx    r13 %08lx    r14 %08lx    r15 %08lx\n"
                "  r16 %08lx    r17 %08lx    r18 %08lx    r19 %08lx\n"
                "  r20 %08lx    r21 %08lx    r22 %08lx    r23 %08lx\n"
                "  r24 %08lx    r25 %08lx    r26 %08lx    r27 %08lx\n"
                "  r28 %08lx    r29 %08lx    r30 %08lx    r31 %08lx\n",
                r->pc, r->lr, r->ctr, r->msr,
                r->xer, r->cr, r->fpscr,
                r->r0, r->r1, r->r2, r->r3,
                r->r4, r->r5, r->r6, r->r7,
                r->r8, r->r9, r->r10, r->r11,
                r->r12, segv_r[13], segv_r[14], segv_r[15],
                segv_r[16], segv_r[17], segv_r[18], segv_r[19],
                segv_r[20], segv_r[21], segv_r[22], segv_r[23],
                segv_r[24], segv_r[25], segv_r[26], segv_r[27],
                segv_r[28], segv_r[29], segv_r[30], segv_r[31]);
        VideoQuitFullScreen();
        disable_debugger(false);
        debugger(str);
        exit(1);
        return;

rti:
        // Restore volatile registers
        r->r0 = segv_r[0];
        r->r1 = segv_r[1];
        r->r2 = segv_r[2];
        r->r3 = segv_r[3];
        r->r4 = segv_r[4];
        r->r5 = segv_r[5];
        r->r6 = segv_r[6];
        r->r7 = segv_r[7];
        r->r8 = segv_r[8];
        r->r9 = segv_r[9];
        r->r10 = segv_r[10];
        r->r11 = segv_r[11];
        r->r12 = segv_r[12];
}


/*
 *  Helpers to share 32-bit addressable data with MacOS
 */

bool SheepMem::Init(void)
{
        // Delete old area
        area_id old_sheep_area = find_area(SHEEP_AREA_NAME);
        if (old_sheep_area > 0)
                delete_area(old_sheep_area);

        // Create area for SheepShaver data
        proc = base = 0x60000000;
        SheepMemArea = create_area(SHEEP_AREA_NAME, (void **)&base, B_BASE_ADDRESS, size, B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
        if (SheepMemArea < 0)
                return false;

        // Create read-only area with all bits set to 0
        static const uint8 const_zero_page[4096] = {0,};
        zero_page = const_zero_page;

        D(bug("SheepShaver area %ld at %p\n", SheepMemArea, base));
        data = base + size;
        return true;
}

void SheepMem::Exit(void)
{
        if (SheepMemArea >= 0)
                delete_area(SheepMemArea);
}


/*
 *  Display error alert
 */

void ErrorAlert(const char *text)
{
        if (PrefsFindBool("nogui")) {
                printf(GetString(STR_SHELL_ERROR_PREFIX), text);
                return;
        }
        char str[256];
        sprintf(str, GetString(STR_GUI_ERROR_PREFIX), text);
        VideoQuitFullScreen();
        BAlert *alert = new BAlert(GetString(STR_ERROR_ALERT_TITLE), str, GetString(STR_QUIT_BUTTON), NULL, NULL, B_WIDTH_AS_USUAL, B_STOP_ALERT);
        alert->Go();
}


/*
 *  Display warning alert
 */

void WarningAlert(const char *text)
{
        if (PrefsFindBool("nogui")) {
                printf(GetString(STR_SHELL_WARNING_PREFIX), text);
                return;
        }
        char str[256];
        sprintf(str, GetString(STR_GUI_WARNING_PREFIX), text);
        BAlert *alert = new BAlert(GetString(STR_WARNING_ALERT_TITLE), str, GetString(STR_OK_BUTTON), NULL, NULL, B_WIDTH_AS_USUAL, B_INFO_ALERT);
        alert->Go();
}


/*
 *  Display choice alert
 */

bool ChoiceAlert(const char *text, const char *pos, const char *neg)
{
        char str[256];
        sprintf(str, GetString(STR_GUI_WARNING_PREFIX), text);
        BAlert *alert = new BAlert(GetString(STR_WARNING_ALERT_TITLE), str, pos, neg, NULL, B_WIDTH_AS_USUAL, B_INFO_ALERT);
        return alert->Go() == 0;
}
Revision:	1.17
Committed:	2005-01-30T21:48:19Z (19 years, 10 months ago) by gbeauche
Branch:	MAIN
Changes since 1.16:	+1 -1 lines
Log Message:	Happy New Year 2005!