src/Unix/main_unix.cpp

/*
 *  main_unix.cpp - Emulation core, Unix implementation
 *
 *  SheepShaver (C) 1997-2002 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:
 *
 *  See main_beos.cpp for a description of the three operating modes.
 *
 *  In addition to that, we have to handle the fact that the MacOS ABI
 *  is slightly different from the SysV ABI used by Linux:
 *    - Stack frames are different (e.g. LR is stored in 8(r1) under
 *      MacOS, but in 4(r1) under Linux)
 *    - There is no TOC under Linux; r2 is free for the user
 *    - r13 is used as a small data pointer under Linux (but appearently
 *      it is not used this way? To be sure, we specify -msdata=none
 *      in the Makefile)
 *    - As there is no TOC, there are also no TVECTs under Linux;
 *      function pointers point directly to the function code
 *  The Execute*() functions have to account for this. Additionally, we
 *  cannot simply call MacOS functions by getting their TVECT and jumping
 *  to it. Such calls are done via the call_macos*() functions in
 *  asm_linux.S that create a MacOS stack frame, load the TOC pointer
 *  and put the arguments into the right registers.
 *
 *  As on the BeOS, we have to specify an alternate signal stack because
 *  interrupts (and, under Linux, Low Memory accesses) may occur when r1
 *  is pointing to the Kernel Data or to Low Memory. There is one
 *  problem, however, due to the alternate signal stack being global to
 *  all signal handlers. Consider the following scenario:
 *    - The main thread is executing some native PPC MacOS code in
 *      MODE_NATIVE, running on the MacOS stack (somewhere in the Mac RAM).
 *    - A SIGUSR2 interrupt occurs. The kernel switches to the signal
 *      stack and starts executing the SIGUSR2 signal handler.
 *    - The signal handler sees the MODE_NATIVE and calls ppc_interrupt()
 *      to handle a native interrupt.
 *    - ppc_interrupt() sets r1 to point to the Kernel Data and jumps to
 *      the nanokernel.
 *    - The nanokernel accesses a Low Memory global (most likely one of
 *      the XLMs), a SIGSEGV occurs.
 *    - The kernel sees that r1 does not point to the signal stack and
 *      switches to the signal stack again, thus overwriting the data that
 *      the SIGUSR2 handler put there.
 *  The same problem arises when calling ExecutePPC() inside the MODE_EMUL_OP
 *  interrupt handler.
 *
 *  The solution is to set the signal stack to a second, "extra" stack
 *  inside the SIGUSR2 handler before entering the Nanokernel or calling
 *  ExecutePPC (or any function that might cause a mode switch). The signal
 *  stack is restored before exiting the SIGUSR2 handler.
 *
 *  TODO:
 *    check if SIGSEGV handler works for all registers (including FP!)
 */

#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <signal.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 "sony.h"
#include "disk.h"
#include "cdrom.h"
#include "scsi.h"
#include "video.h"
#include "audio.h"
#include "ether.h"
#include "serial.h"
#include "clip.h"
#include "extfs.h"
#include "sys.h"
#include "macos_util.h"
#include "rom_patches.h"
#include "user_strings.h"
#include "vm_alloc.h"
#include "sigsegv.h"
#include "thunks.h"

#define DEBUG 0
#include "debug.h"


#include <X11/Xlib.h>

#ifdef ENABLE_GTK
#include <gtk/gtk.h>
#endif

#ifdef ENABLE_XF86_DGA
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/xf86dga.h>
#endif

#ifdef ENABLE_MON
#include "mon.h"
#endif


// Enable Execute68k() safety checks?
#define SAFE_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 ROM_FILE_NAME[] = "ROM";
const char ROM_FILE_NAME2[] = "Mac OS ROM";

const uintptr RAM_BASE = 0x20000000;            // Base address of RAM
const uint32 SIG_STACK_SIZE = 0x10000;          // Size of signal stack


#if !EMULATED_PPC
// Structure in which registers are saved in a signal handler;
// sigcontext->regs points to it
// (see arch/ppc/kernel/signal.c)
typedef struct {
        uint32 u[4];
} __attribute((aligned(16))) vector128;
#include <linux/elf.h>

struct sigregs {
        elf_gregset_t   gp_regs;                                // Identical to pt_regs
        double                  fp_regs[ELF_NFPREG];    // f0..f31 and fpsrc
        //more (uninteresting) stuff following here
};
#endif


// Global variables (exported)
#if !EMULATED_PPC
void *TOC;                              // Small data pointer (r13)
#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 PVR;                             // Theoretical PVR
int64 CPUClockSpeed;    // Processor clock speed (Hz)
int64 BusClockSpeed;    // Bus clock speed (Hz)


// Global variables
char *x_display_name = NULL;                            // X11 display name
Display *x_display = NULL;                                      // X11 display handle
#ifdef X11_LOCK_TYPE
X11_LOCK_TYPE x_display_lock = X11_LOCK_INIT; // X11 display lock
#endif

static int zero_fd = 0;                                         // FD of /dev/zero
static bool lm_area_mapped = false;                     // Flag: Low Memory area mmap()ped
static int kernel_area = -1;                            // SHM ID of Kernel Data area
static bool rom_area_mapped = false;            // Flag: Mac ROM mmap()ped
static bool ram_area_mapped = false;            // Flag: Mac RAM mmap()ped
static KernelData *kernel_data;                         // Pointer to Kernel Data
static EmulatorData *emulator_data;

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

static bool nvram_thread_active = false;        // Flag: NVRAM watchdog installed
static pthread_t nvram_thread;                          // NVRAM watchdog
static bool tick_thread_active = false;         // Flag: MacOS thread installed
static pthread_t tick_thread;                           // 60Hz thread
static pthread_t emul_thread;                           // MacOS thread

static bool ready_for_signals = false;          // Handler installed, signals can be sent
static int64 num_segv = 0;                                      // Number of handled SEGV signals

static struct sigaction sigusr2_action;         // Interrupt signal (of emulator thread)
#if EMULATED_PPC
static uintptr sig_stack = 0;                           // Stack for PowerPC interrupt routine
#else
static struct sigaction sigsegv_action;         // Data access exception signal (of emulator thread)
static struct sigaction sigill_action;          // Illegal instruction signal (of emulator thread)
static void *sig_stack = NULL;                          // Stack for signal handlers
static void *extra_stack = NULL;                        // Stack for SIGSEGV inside interrupt handler
static bool emul_thread_fatal = false;          // Flag: MacOS thread crashed, tick thread shall dump debug output
static sigregs sigsegv_regs;                            // Register dump when crashed
#endif

uintptr SheepMem::zero_page = 0;                        // Address of ro page filled in with zeros
uintptr SheepMem::base = 0x60000000;            // Address of SheepShaver data
uintptr SheepMem::top = 0;                                      // Top of SheepShaver data (stack like storage)


// Prototypes
static void Quit(void);
static void *emul_func(void *arg);
static void *nvram_func(void *arg);
static void *tick_func(void *arg);
#if EMULATED_PPC
static void sigusr2_handler(int sig);
extern void emul_ppc(uint32 start);
extern void init_emul_ppc(void);
extern void exit_emul_ppc(void);
#else
static void sigusr2_handler(int sig, sigcontext_struct *sc);
static void sigsegv_handler(int sig, sigcontext_struct *sc);
static void sigill_handler(int sig, sigcontext_struct *sc);
#endif


// From asm_linux.S
#if !EMULATED_PPC
extern "C" void *get_toc(void);
extern "C" void *get_sp(void);
extern "C" void flush_icache_range(void *start, void *end);
extern "C" void jump_to_rom(uint32 entry, uint32 context);
extern "C" void quit_emulator(void);
extern "C" void execute_68k(uint32 pc, M68kRegisters *r);
extern "C" void ppc_interrupt(uint32 entry, uint32 kernel_data);
extern "C" int atomic_add(int *var, int v);
extern "C" int atomic_and(int *var, int v);
extern "C" int atomic_or(int *var, int v);
extern void paranoia_check(void);
#endif


#if EMULATED_PPC
/*
 *  Return signal stack base
 */

uintptr SignalStackBase(void)
{
        return sig_stack + SIG_STACK_SIZE;
}


/*
 *  Atomic operations
 */

#if HAVE_SPINLOCKS
static spinlock_t atomic_ops_lock = SPIN_LOCK_UNLOCKED;
#else
#define spin_lock(LOCK)
#define spin_unlock(LOCK)
#endif

int atomic_add(int *var, int v)
{
        spin_lock(&atomic_ops_lock);
        int ret = *var;
        *var += v;
        spin_unlock(&atomic_ops_lock);
        return ret;
}

int atomic_and(int *var, int v)
{
        spin_lock(&atomic_ops_lock);
        int ret = *var;
        *var &= v;
        spin_unlock(&atomic_ops_lock);
        return ret;
}

int atomic_or(int *var, int v)
{
        spin_lock(&atomic_ops_lock);
        int ret = *var;
        *var |= v;
        spin_unlock(&atomic_ops_lock);
        return ret;
}
#endif


/*
 *  Main program
 */

static void usage(const char *prg_name)
{
        printf("Usage: %s [OPTION...]\n", prg_name);
        printf("\nUnix options:\n");
        printf("  --display STRING\n    X display to use\n");
        PrefsPrintUsage();
        exit(0);
}

int main(int argc, char **argv)
{
        char str[256];
        uint32 *boot_globs;
        int16 i16;
        int rom_fd;
        FILE *proc_file;
        const char *rom_path;
        uint32 rom_size, actual;
        uint8 *rom_tmp;
        time_t now, expire;

        // Initialize variables
        RAMBase = 0;
        tzset();

        // 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

#ifdef ENABLE_GTK
        // Init GTK
        gtk_set_locale();
        gtk_init(&argc, &argv);
#endif

        // Read preferences
        PrefsInit(argc, argv);

        // Parse command line arguments
        for (int i=1; i<argc; i++) {
                if (strcmp(argv[i], "--help") == 0) {
                        usage(argv[0]);
                } else if (strcmp(argv[i], "--display") == 0) {
                        i++;
                        if (i < argc)
                                x_display_name = strdup(argv[i]);
                } else if (argv[i][0] == '-') {
                        fprintf(stderr, "Unrecognized option '%s'\n", argv[i]);
                        usage(argv[0]);
                }
        }

        // Open display
        x_display = XOpenDisplay(x_display_name);
        if (x_display == NULL) {
                char str[256];
                sprintf(str, GetString(STR_NO_XSERVER_ERR), XDisplayName(x_display_name));
                ErrorAlert(str);
                goto quit;
        }

#if defined(ENABLE_XF86_DGA) && !defined(ENABLE_MON)
        // Fork out, so we can return from fullscreen mode when things get ugly
        XF86DGAForkApp(DefaultScreen(x_display));
#endif

#ifdef ENABLE_MON
        // Initialize mon
        mon_init();
#endif

        // Get system info
        PVR = 0x00040000;                       // Default: 604
        CPUClockSpeed = 100000000;      // Default: 100MHz
        BusClockSpeed = 100000000;      // Default: 100MHz
#if !EMULATED_PPC
        proc_file = fopen("/proc/cpuinfo", "r");
        if (proc_file) {
                char line[256];
                while(fgets(line, 255, proc_file)) {
                        // Read line
                        int len = strlen(line);
                        if (len == 0)
                                continue;
                        line[len-1] = 0;

                        // Parse line
                        int i;
                        char value[256];
                        if (sscanf(line, "cpu : %s", value) == 1) {
                                if (strcmp(value, "601") == 0)
                                        PVR = 0x00010000;
                                else if (strcmp(value, "603") == 0)
                                        PVR = 0x00030000;
                                else if (strcmp(value, "604") == 0)
                                        PVR = 0x00040000;
                                else if (strcmp(value, "603e") == 0)
                                        PVR = 0x00060000;
                                else if (strcmp(value, "603ev") == 0)
                                        PVR = 0x00070000;
                                else if (strcmp(value, "604e") == 0)
                                        PVR = 0x00090000;
                                else if (strcmp(value, "604ev5") == 0)
                                        PVR = 0x000a0000;
                                else if (strcmp(value, "750") == 0)
                                        PVR = 0x00080000;
                                else if (strcmp(value, "821") == 0)
                                        PVR = 0x00320000;
                                else if (strcmp(value, "860") == 0)
                                        PVR = 0x00500000;
                                else
                                        printf("WARNING: Unknown CPU type '%s', assuming 604\n", value);
                        }
                        if (sscanf(line, "clock : %dMHz", &i) == 1)
                                CPUClockSpeed = BusClockSpeed = i * 1000000;
                }
                fclose(proc_file);
        } else {
                sprintf(str, GetString(STR_PROC_CPUINFO_WARN), strerror(errno));
                WarningAlert(str);
        }
#endif
        D(bug("PVR: %08x (assumed)\n", PVR));

        // Init system routines
        SysInit();

        // Show preferences editor
        if (!PrefsFindBool("nogui"))
                if (!PrefsEditor())
                        goto quit;

#if !EMULATED_PPC
        // Check some things
        paranoia_check();
#endif

        // Open /dev/zero
        zero_fd = open("/dev/zero", O_RDWR);
        if (zero_fd < 0) {
                sprintf(str, GetString(STR_NO_DEV_ZERO_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Create Low Memory area (0x0000..0x3000)
        if (vm_acquire_fixed((char *)0, 0x3000) < 0) {
                sprintf(str, GetString(STR_LOW_MEM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        lm_area_mapped = true;

        // Create areas for Kernel Data
        kernel_area = shmget(IPC_PRIVATE, KERNEL_AREA_SIZE, 0600);
        if (kernel_area == -1) {
                sprintf(str, GetString(STR_KD_SHMGET_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        if (shmat(kernel_area, (void *)KERNEL_DATA_BASE, 0) < 0) {
                sprintf(str, GetString(STR_KD_SHMAT_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        if (shmat(kernel_area, (void *)KERNEL_DATA2_BASE, 0) < 0) {
                sprintf(str, GetString(STR_KD2_SHMAT_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        kernel_data = (KernelData *)KERNEL_DATA_BASE;
        emulator_data = &kernel_data->ed;
        KernelDataAddr = KERNEL_DATA_BASE;
        D(bug("Kernel Data at %p, Emulator Data at %p\n", kernel_data, emulator_data));

        // Create area for SheepShaver data
        if (!SheepMem::Init()) {
                sprintf(str, GetString(STR_SHEEP_MEM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Create area for Mac ROM
        if (vm_acquire_fixed((char *)ROM_BASE, ROM_AREA_SIZE) < 0) {
                sprintf(str, GetString(STR_ROM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#if !EMULATED_PPC || defined(__powerpc__)
        if (vm_protect((char *)ROM_BASE, ROM_AREA_SIZE, VM_PAGE_READ | VM_PAGE_WRITE | VM_PAGE_EXECUTE) < 0) {
                sprintf(str, GetString(STR_ROM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif
        rom_area_mapped = true;
        D(bug("ROM area at %08x\n", ROM_BASE));

        // Create area for Mac RAM
        RAMSize = PrefsFindInt32("ramsize");
        if (RAMSize < 8*1024*1024) {
                WarningAlert(GetString(STR_SMALL_RAM_WARN));
                RAMSize = 8*1024*1024;
        }

        if (vm_acquire_fixed((char *)RAM_BASE, RAMSize) < 0) {
                sprintf(str, GetString(STR_RAM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#if !EMULATED_PPC
        if (vm_protect((char *)RAM_BASE, RAMSize, VM_PAGE_READ | VM_PAGE_WRITE | VM_PAGE_EXECUTE) < 0) {
                sprintf(str, GetString(STR_RAM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif
        RAMBase = RAM_BASE;
        ram_area_mapped = true;
        D(bug("RAM area at %08x\n", RAMBase));

        if (RAMBase > ROM_BASE) {
                ErrorAlert(GetString(STR_RAM_HIGHER_THAN_ROM_ERR));
                goto quit;
        }

        // Load Mac ROM
        rom_path = PrefsFindString("rom");
        rom_fd = open(rom_path ? rom_path : ROM_FILE_NAME, O_RDONLY);
        if (rom_fd < 0) {
                rom_fd = open(rom_path ? rom_path : ROM_FILE_NAME2, O_RDONLY);
                if (rom_fd < 0) {
                        ErrorAlert(GetString(STR_NO_ROM_FILE_ERR));
                        goto quit;
                }
        }
        printf(GetString(STR_READING_ROM_FILE));
        rom_size = lseek(rom_fd, 0, SEEK_END);
        lseek(rom_fd, 0, SEEK_SET);
        rom_tmp = new uint8[ROM_SIZE];
        actual = read(rom_fd, (void *)rom_tmp, ROM_SIZE);
        close(rom_fd);
        
        // Decode Mac ROM
        if (!DecodeROM(rom_tmp, actual)) {
                if (rom_size != 4*1024*1024) {
                        ErrorAlert(GetString(STR_ROM_SIZE_ERR));
                        goto quit;
                } else {
                        ErrorAlert(GetString(STR_ROM_FILE_READ_ERR));
                        goto quit;
                }
        }
        delete[] rom_tmp;

        // Load NVRAM
        XPRAMInit();

        // Set boot volume
        i16 = PrefsFindInt32("bootdrive");
        XPRAM[0x1378] = i16 >> 8;
        XPRAM[0x1379] = i16 & 0xff;
        i16 = PrefsFindInt32("bootdriver");
        XPRAM[0x137a] = i16 >> 8;
        XPRAM[0x137b] = i16 & 0xff;

        // Create BootGlobs at top of Mac memory
        memset((void *)(RAMBase + RAMSize - 4096), 0, 4096);
        BootGlobsAddr = RAMBase + RAMSize - 0x1c;
        boot_globs = (uint32 *)BootGlobsAddr;
        boot_globs[-5] = htonl(RAMBase + RAMSize);      // MemTop
        boot_globs[0] = htonl(RAMBase);                         // First RAM bank
        boot_globs[1] = htonl(RAMSize);
        boot_globs[2] = htonl((uint32)-1);                      // End of bank table

        // Init thunks
        if (!ThunksInit())
                goto quit;

        // Init drivers
        SonyInit();
        DiskInit();
        CDROMInit();
        SCSIInit();

        // Init external file system
        ExtFSInit(); 

        // Init audio
        AudioInit();

        // Init network
        EtherInit();

        // Init serial ports
        SerialInit();

        // Init Time Manager
        TimerInit();

        // Init clipboard
        ClipInit();

        // Init video
        if (!VideoInit())
                goto quit;

        // Install ROM patches
        if (!PatchROM()) {
                ErrorAlert(GetString(STR_UNSUPPORTED_ROM_TYPE_ERR));
                goto quit;
        }

        // Clear caches (as we loaded and patched code) and write protect ROM
#if !EMULATED_PPC
        MakeExecutable(0, (void *)ROM_BASE, ROM_AREA_SIZE);
#endif
        vm_protect((char *)ROM_BASE, ROM_AREA_SIZE, VM_PAGE_READ | VM_PAGE_EXECUTE);

        // Initialize Kernel Data
        memset(kernel_data, 0, sizeof(KernelData));
        if (ROMType == ROMTYPE_NEWWORLD) {
                uintptr of_dev_tree = SheepMem::Reserve(4 * sizeof(uint32));
                memset((void *)of_dev_tree, 0, 4 * sizeof(uint32));
                uintptr vector_lookup_tbl = SheepMem::Reserve(128);
                uintptr vector_mask_tbl = SheepMem::Reserve(64);
                memset((uint8 *)kernel_data + 0xb80, 0x3d, 0x80);
                memset((void *)vector_lookup_tbl, 0, 128);
                memset((void *)vector_mask_tbl, 0, 64);
                kernel_data->v[0xb80 >> 2] = htonl(ROM_BASE);
                kernel_data->v[0xb84 >> 2] = htonl(of_dev_tree);                        // OF device tree base
                kernel_data->v[0xb90 >> 2] = htonl(vector_lookup_tbl);
                kernel_data->v[0xb94 >> 2] = htonl(vector_mask_tbl);
                kernel_data->v[0xb98 >> 2] = htonl(ROM_BASE);                           // OpenPIC base
                kernel_data->v[0xbb0 >> 2] = htonl(0);                                          // ADB base
                kernel_data->v[0xc20 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc24 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc30 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc34 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc38 >> 2] = htonl(0x00010020);
                kernel_data->v[0xc3c >> 2] = htonl(0x00200001);
                kernel_data->v[0xc40 >> 2] = htonl(0x00010000);
                kernel_data->v[0xc50 >> 2] = htonl(RAMBase);
                kernel_data->v[0xc54 >> 2] = htonl(RAMSize);
                kernel_data->v[0xf60 >> 2] = htonl(PVR);
                kernel_data->v[0xf64 >> 2] = htonl(CPUClockSpeed);
                kernel_data->v[0xf68 >> 2] = htonl(BusClockSpeed);
                kernel_data->v[0xf6c >> 2] = htonl(CPUClockSpeed);
        } else {
                kernel_data->v[0xc80 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc84 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc90 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc94 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc98 >> 2] = htonl(0x00010020);
                kernel_data->v[0xc9c >> 2] = htonl(0x00200001);
                kernel_data->v[0xca0 >> 2] = htonl(0x00010000);
                kernel_data->v[0xcb0 >> 2] = htonl(RAMBase);
                kernel_data->v[0xcb4 >> 2] = htonl(RAMSize);
                kernel_data->v[0xf80 >> 2] = htonl(PVR);
                kernel_data->v[0xf84 >> 2] = htonl(CPUClockSpeed);
                kernel_data->v[0xf88 >> 2] = htonl(BusClockSpeed);
                kernel_data->v[0xf8c >> 2] = htonl(CPUClockSpeed);
        }

        // Initialize extra low memory
        D(bug("Initializing Low Memory...\n"));
        memset(NULL, 0, 0x3000);
        WriteMacInt32(XLM_SIGNATURE, FOURCC('B','a','a','h'));                  // Signature to detect SheepShaver
        WriteMacInt32(XLM_KERNEL_DATA, KernelDataAddr);                                 // For trap replacement routines
        WriteMacInt32(XLM_PVR, PVR);                                                                    // Theoretical PVR
        WriteMacInt32(XLM_BUS_CLOCK, BusClockSpeed);                                    // For DriverServicesLib patch
        WriteMacInt16(XLM_EXEC_RETURN_OPCODE, M68K_EXEC_RETURN);                // For Execute68k() (RTS from the executed 68k code will jump here and end 68k mode)
        WriteMacInt32(XLM_ZERO_PAGE, SheepMem::ZeroPage());                             // Pointer to read-only page with all bits set to 0
#if !EMULATED_PPC
        WriteMacInt32(XLM_TOC, (uint32)TOC);                                                            // TOC pointer of emulator
#endif
        WriteMacInt32(XLM_ETHER_INIT, NativeFunction(NATIVE_ETHER_INIT));       // DLPI ethernet driver functions
        WriteMacInt32(XLM_ETHER_TERM, NativeFunction(NATIVE_ETHER_TERM));
        WriteMacInt32(XLM_ETHER_OPEN, NativeFunction(NATIVE_ETHER_OPEN));
        WriteMacInt32(XLM_ETHER_CLOSE, NativeFunction(NATIVE_ETHER_CLOSE));
        WriteMacInt32(XLM_ETHER_WPUT, NativeFunction(NATIVE_ETHER_WPUT));
        WriteMacInt32(XLM_ETHER_RSRV, NativeFunction(NATIVE_ETHER_RSRV));
        WriteMacInt32(XLM_VIDEO_DOIO, NativeFunction(NATIVE_VIDEO_DO_DRIVER_IO));
        D(bug("Low Memory initialized\n"));

        // Start 60Hz thread
        tick_thread_active = (pthread_create(&tick_thread, NULL, tick_func, NULL) == 0);
        D(bug("Tick thread installed (%ld)\n", tick_thread));

        // Start NVRAM watchdog thread
        memcpy(last_xpram, XPRAM, XPRAM_SIZE);
        nvram_thread_active = (pthread_create(&nvram_thread, NULL, nvram_func, NULL) == 0);
        D(bug("NVRAM thread installed (%ld)\n", nvram_thread));

#if !EMULATED_PPC
        // Create and install stacks for signal handlers
        sig_stack = malloc(SIG_STACK_SIZE);
        D(bug("Signal stack at %p\n", sig_stack));
        if (sig_stack == NULL) {
                ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR));
                goto quit;
        }
        extra_stack = malloc(SIG_STACK_SIZE);
        D(bug("Extra stack at %p\n", extra_stack));
        if (extra_stack == NULL) {
                ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR));
                goto quit;
        }
        struct sigaltstack new_stack;
        new_stack.ss_sp = sig_stack;
        new_stack.ss_flags = 0;
        new_stack.ss_size = SIG_STACK_SIZE;
        if (sigaltstack(&new_stack, NULL) < 0) {
                sprintf(str, GetString(STR_SIGALTSTACK_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif

#if !EMULATED_PPC
        // Install SIGSEGV handler
        sigemptyset(&sigsegv_action.sa_mask);   // Block interrupts during SEGV handling
        sigaddset(&sigsegv_action.sa_mask, SIGUSR2);
        sigsegv_action.sa_handler = (__sighandler_t)sigsegv_handler;
        sigsegv_action.sa_flags = SA_ONSTACK;
        sigsegv_action.sa_restorer = NULL;
        if (sigaction(SIGSEGV, &sigsegv_action, NULL) < 0) {
                sprintf(str, GetString(STR_SIGSEGV_INSTALL_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Install SIGILL handler
        sigemptyset(&sigill_action.sa_mask);    // Block interrupts during ILL handling
        sigaddset(&sigill_action.sa_mask, SIGUSR2);
        sigill_action.sa_handler = (__sighandler_t)sigill_handler;
        sigill_action.sa_flags = SA_ONSTACK;
        sigill_action.sa_restorer = NULL;
        if (sigaction(SIGILL, &sigill_action, NULL) < 0) {
                sprintf(str, GetString(STR_SIGILL_INSTALL_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif

        // Install interrupt signal handler
        sigemptyset(&sigusr2_action.sa_mask);
        sigusr2_action.sa_handler = (__sighandler_t)sigusr2_handler;
        sigusr2_action.sa_flags = 0;
#if !EMULATED_PPC
        sigusr2_action.sa_flags = SA_ONSTACK | SA_RESTART;
#endif
        sigusr2_action.sa_restorer = NULL;
        if (sigaction(SIGUSR2, &sigusr2_action, NULL) < 0) {
                sprintf(str, GetString(STR_SIGUSR2_INSTALL_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Get my thread ID and execute MacOS thread function
        emul_thread = pthread_self();
        D(bug("MacOS thread is %ld\n", emul_thread));
        emul_func(NULL);

quit:
        Quit();
        return 0;
}


/*
 *  Cleanup and quit
 */

static void Quit(void)
{
#if EMULATED_PPC
        // Exit PowerPC emulation
        exit_emul_ppc();
#endif

        // Stop 60Hz thread
        if (tick_thread_active) {
                pthread_cancel(tick_thread);
                pthread_join(tick_thread, NULL);
        }

        // Stop NVRAM watchdog thread
        if (nvram_thread_active) {
                pthread_cancel(nvram_thread);
                pthread_join(nvram_thread, NULL);
        }

#if !EMULATED_PPC
        // Uninstall SIGSEGV handler
        sigemptyset(&sigsegv_action.sa_mask);
        sigsegv_action.sa_handler = SIG_DFL;
        sigsegv_action.sa_flags = 0;
        sigaction(SIGSEGV, &sigsegv_action, NULL);

        // Uninstall SIGILL handler
        sigemptyset(&sigill_action.sa_mask);
        sigill_action.sa_handler = SIG_DFL;
        sigill_action.sa_flags = 0;
        sigaction(SIGILL, &sigill_action, NULL);
#endif

        // Save NVRAM
        XPRAMExit();

        // Exit clipboard
        ClipExit();

        // Exit Time Manager
        TimerExit();

        // Exit serial
        SerialExit();

        // Exit network
        EtherExit();

        // Exit audio
        AudioExit();

        // Exit video
        VideoExit();

        // Exit external file system
        ExtFSExit();

        // Exit drivers
        SCSIExit();
        CDROMExit();
        DiskExit();
        SonyExit();

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

        // Delete RAM area
        if (ram_area_mapped)
                vm_release((char *)RAM_BASE, RAMSize);

        // Delete ROM area
        if (rom_area_mapped)
                vm_release((char *)ROM_BASE, ROM_AREA_SIZE);

        // Delete Kernel Data area
        if (kernel_area >= 0) {
                shmdt((void *)KERNEL_DATA_BASE);
                shmdt((void *)KERNEL_DATA2_BASE);
                shmctl(kernel_area, IPC_RMID, NULL);
        }

        // Delete Low Memory area
        if (lm_area_mapped)
                munmap((char *)0x0000, 0x3000);

        // Close /dev/zero
        if (zero_fd > 0)
                close(zero_fd);

        // Exit system routines
        SysExit();

        // Exit preferences
        PrefsExit();

#ifdef ENABLE_MON
        // Exit mon
        mon_exit();
#endif

        // Close X11 server connection
        if (x_display)
                XCloseDisplay(x_display);

        exit(0);
}


/*
 *  Jump into Mac ROM, start 680x0 emulator
 */

#if EMULATED_PPC
void jump_to_rom(uint32 entry)
{
        init_emul_ppc();
        emul_ppc(entry);
}
#endif


/*
 *  Emulator thread function
 */

static void *emul_func(void *arg)
{
        // We're now ready to receive signals
        ready_for_signals = true;

        // Decrease priority, so more time-critical things like audio will work better
        nice(1);

        // Jump to ROM boot routine
        D(bug("Jumping to ROM\n"));
#if EMULATED_PPC
        jump_to_rom(ROM_BASE + 0x310000);
#else
        jump_to_rom(ROM_BASE + 0x310000, (uint32)emulator_data);
#endif
        D(bug("Returned from ROM\n"));

        // We're no longer ready to receive signals
        ready_for_signals = false;
        return NULL;
}


#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
 */

void Execute68k(uint32 pc, M68kRegisters *r)
{
#if SAFE_EXEC_68K
        if (ReadMacInt32(XLM_RUN_MODE) != MODE_EMUL_OP)
                printf("FATAL: Execute68k() not called from EMUL_OP mode\n");
        if (!pthread_equal(pthread_self(), emul_thread))
                printf("FATAL: Execute68k() not called from emul_thread\n");
#endif
        execute_68k(pc, r);
}


/*
 *  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);
}
#endif


/*
 *  Quit emulator (cause return from jump_to_rom)
 */

void QuitEmulator(void)
{
#if EMULATED_PPC
        Quit();
#else
        quit_emulator();
#endif
}


/*
 *  Pause/resume emulator
 */

void PauseEmulator(void)
{
        pthread_kill(emul_thread, SIGSTOP);
}

void ResumeEmulator(void)
{
        pthread_kill(emul_thread, SIGCONT);
}


/*
 *  Dump 68k registers
 */

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


/*
 *  Make code executable
 */

void MakeExecutable(int dummy, void *start, uint32 length)
{
        if (((uintptr)start >= ROM_BASE) && ((uintptr)start < (ROM_BASE + ROM_SIZE)))
                return;
#if EMULATED_PPC
        FlushCodeCache((uintptr)start, (uintptr)start + length);
#else
        flush_icache_range(start, (void *)((uintptr)start + length));
#endif
}


/*
 *  Patch things after system startup (gets called by disk driver accRun routine)
 */

void PatchAfterStartup(void)
{
        ExecuteNative(NATIVE_VIDEO_INSTALL_ACCEL);
        InstallExtFS();
}


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

static void *nvram_func(void *arg)
{
        struct timespec req = {60, 0};  // 1 minute

        for (;;) {
                pthread_testcancel();
                nanosleep(&req, NULL);
                pthread_testcancel();
                if (memcmp(last_xpram, XPRAM, XPRAM_SIZE)) {
                        memcpy(last_xpram, XPRAM, XPRAM_SIZE);
                        SaveXPRAM();
                }
        }
        return NULL;
}


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

static void *tick_func(void *arg)
{
        int tick_counter = 0;
        struct timespec req = {0, 16625000};

        for (;;) {

                // Wait
                nanosleep(&req, NULL);

#if !EMULATED_PPC
                // Did we crash?
                if (emul_thread_fatal) {

                        // Yes, dump registers
                        pt_regs *r = (pt_regs *)&sigsegv_regs;
                        char str[256];
                        sprintf(str, "SIGSEGV\n"
                                "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                                "  xer %08lx     cr %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->nip, r->link, r->ctr, r->msr,
                                r->xer, r->ccr,
                                r->gpr[0], r->gpr[1], r->gpr[2], r->gpr[3],
                                r->gpr[4], r->gpr[5], r->gpr[6], r->gpr[7],
                                r->gpr[8], r->gpr[9], r->gpr[10], r->gpr[11],
                                r->gpr[12], r->gpr[13], r->gpr[14], r->gpr[15],
                                r->gpr[16], r->gpr[17], r->gpr[18], r->gpr[19],
                                r->gpr[20], r->gpr[21], r->gpr[22], r->gpr[23],
                                r->gpr[24], r->gpr[25], r->gpr[26], r->gpr[27],
                                r->gpr[28], r->gpr[29], r->gpr[30], r->gpr[31]);
                        printf(str);
                        VideoQuitFullScreen();

#ifdef ENABLE_MON
                        // Start up mon in real-mode
                        printf("Welcome to the sheep factory.\n");
                        char *arg[4] = {"mon", "-m", "-r", NULL};
                        mon(3, arg);
#endif
                        return NULL;
                }
#endif

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

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


/*
 *  Pthread configuration
 */

void Set_pthread_attr(pthread_attr_t *attr, int priority)
{
#ifdef HAVE_PTHREADS
        pthread_attr_init(attr);
#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
        // Some of these only work for superuser
        if (geteuid() == 0) {
                pthread_attr_setinheritsched(attr, PTHREAD_EXPLICIT_SCHED);
                pthread_attr_setschedpolicy(attr, SCHED_FIFO);
                struct sched_param fifo_param;
                fifo_param.sched_priority = ((sched_get_priority_min(SCHED_FIFO) + 
                                              sched_get_priority_max(SCHED_FIFO)) / 2 +
                                             priority);
                pthread_attr_setschedparam(attr, &fifo_param);
        }
        if (pthread_attr_setscope(attr, PTHREAD_SCOPE_SYSTEM) != 0) {
#ifdef PTHREAD_SCOPE_BOUND_NP
            // If system scope is not available (eg. we're not running
            // with CAP_SCHED_MGT capability on an SGI box), try bound
            // scope.  It exposes pthread scheduling to the kernel,
            // without setting realtime priority.
            pthread_attr_setscope(attr, PTHREAD_SCOPE_BOUND_NP);
#endif
        }
#endif
#endif
}


/*
 *  Mutexes
 */

#ifdef HAVE_PTHREADS

struct B2_mutex {
        B2_mutex() { 
            pthread_mutexattr_t attr;
            pthread_mutexattr_init(&attr);
            // Initialize the mutex for priority inheritance --
            // required for accurate timing.
#ifdef HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL
            pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT);
#endif
#if defined(HAVE_PTHREAD_MUTEXATTR_SETTYPE) && defined(PTHREAD_MUTEX_NORMAL)
            pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
#endif
#ifdef HAVE_PTHREAD_MUTEXATTR_SETPSHARED
            pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE);
#endif
            pthread_mutex_init(&m, &attr);
            pthread_mutexattr_destroy(&attr);
        }
        ~B2_mutex() { 
            pthread_mutex_trylock(&m); // Make sure it's locked before
            pthread_mutex_unlock(&m);  // unlocking it.
            pthread_mutex_destroy(&m);
        }
        pthread_mutex_t m;
};

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

void B2_lock_mutex(B2_mutex *mutex)
{
        pthread_mutex_lock(&mutex->m);
}

void B2_unlock_mutex(B2_mutex *mutex)
{
        pthread_mutex_unlock(&mutex->m);
}

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

#else

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;
}

#endif


/*
 *  Trigger signal USR2 from another thread
 */

#if !EMULATED_PPC || ASYNC_IRQ
void TriggerInterrupt(void)
{
        if (ready_for_signals)
                pthread_kill(emul_thread, SIGUSR2);
}
#endif


/*
 *  Interrupt flags (must be handled atomically!)
 */

volatile uint32 InterruptFlags = 0;

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

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


/*
 *  Disable interrupts
 */

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


/*
 *  Enable interrupts
 */

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


/*
 *  USR2 handler
 */

#if EMULATED_PPC
static void sigusr2_handler(int sig)
{
#if ASYNC_IRQ
        extern void HandleInterrupt(void);
        HandleInterrupt();
#endif
}
#else
static void sigusr2_handler(int sig, sigcontext_struct *sc)
{
        pt_regs *r = sc->regs;

        // Do nothing if interrupts are disabled
        if (*(int32 *)XLM_IRQ_NEST > 0)
                return;

        // Disable MacOS stack sniffer
        WriteMacInt32(0x110, 0);

        // Interrupt action depends on current run mode
        switch (ReadMacInt32(XLM_RUN_MODE)) {
                case MODE_68K:
                        // 68k emulator active, trigger 68k interrupt level 1
                        WriteMacInt16(ntohl(kernel_data->v[0x67c >> 2]), 1);
                        r->ccr |= ntohl(kernel_data->v[0x674 >> 2]);
                        break;

#if INTERRUPTS_IN_NATIVE_MODE
                case MODE_NATIVE:
                        // 68k emulator inactive, in nanokernel?
                        if (r->gpr[1] != KernelDataAddr) {
                                // Prepare for 68k interrupt level 1
                                WriteMacInt16(ntohl(kernel_data->v[0x67c >> 2]), 1);
                                WriteMacInt32(ntohl(kernel_data->v[0x658 >> 2]) + 0xdc, ReadMacInt32(ntohl(kernel_data->v[0x658 >> 2]) + 0xdc) | ntohl(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, KernelDataAddr);
                                else
                                        ppc_interrupt(ROM_BASE + 0x312a3c, KernelDataAddr);
                        }
                        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 ((ReadMacInt32(XLM_68K_R25) & 7) == 0) {

                                // Set extra stack for SIGSEGV handler
                                struct sigaltstack new_stack;
                                new_stack.ss_sp = extra_stack;
                                new_stack.ss_flags = 0;
                                new_stack.ss_size = SIG_STACK_SIZE;
                                sigaltstack(&new_stack, NULL);
#if 1
                                // Execute full 68k interrupt routine
                                M68kRegisters r;
                                uint32 old_r25 = ReadMacInt32(XLM_68K_R25);     // Save interrupt level
                                WriteMacInt32(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);
                                WriteMacInt32(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
                                new_stack.ss_sp = sig_stack;
                                new_stack.ss_flags = 0;
                                new_stack.ss_size = SIG_STACK_SIZE;
                                sigaltstack(&new_stack, NULL);
                        }
                        break;
#endif
        }
}
#endif


/*
 *  SIGSEGV handler
 */

#if !EMULATED_PPC
static void sigsegv_handler(int sig, sigcontext_struct *sc)
{
        pt_regs *r = sc->regs;

        // Get effective address
        uint32 addr = r->dar;
        
#if ENABLE_VOSF
        // Handle screen fault.
        extern bool Screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction);
        if (Screen_fault_handler((sigsegv_address_t)addr, (sigsegv_address_t)r->nip))
                return;
#endif

        num_segv++;

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

                // "VM settings" during MacOS 8 installation
                if (r->nip == ROM_BASE + 0x488160 && r->gpr[20] == 0xf8000000) {
                        r->nip += 4;
                        r->gpr[8] = 0;
                        return;
        
                // MacOS 8.5 installation
                } else if (r->nip == ROM_BASE + 0x488140 && r->gpr[16] == 0xf8000000) {
                        r->nip += 4;
                        r->gpr[8] = 0;
                        return;
        
                // MacOS 8 serial drivers on startup
                } else if (r->nip == ROM_BASE + 0x48e080 && (r->gpr[8] == 0xf3012002 || r->gpr[8] == 0xf3012000)) {
                        r->nip += 4;
                        r->gpr[8] = 0;
                        return;
        
                // MacOS 8.1 serial drivers on startup
                } else if (r->nip == ROM_BASE + 0x48c5e0 && (r->gpr[20] == 0xf3012002 || r->gpr[20] == 0xf3012000)) {
                        r->nip += 4;
                        return;
                } else if (r->nip == ROM_BASE + 0x4a10a0 && (r->gpr[20] == 0xf3012002 || r->gpr[20] == 0xf3012000)) {
                        r->nip += 4;
                        return;
                }

                // Get opcode and divide into fields
                uint32 opcode = *((uint32 *)r->nip);
                uint32 primop = opcode >> 26;
                uint32 exop = (opcode >> 1) & 0x3ff;
                uint32 ra = (opcode >> 16) & 0x1f;
                uint32 rb = (opcode >> 11) & 0x1f;
                uint32 rd = (opcode >> 21) & 0x1f;
                int32 imm = (int16)(opcode & 0xffff);

                // 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;
                }
        
                // 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 %08lx, pc %08lx\n", transfer_size == SIZE_BYTE ? "Byte" : transfer_size == SIZE_HALFWORD ? "Halfword" : "Word", addr, r->nip));
                        if (addr_mode == MODE_U || addr_mode == MODE_UX)
                                r->gpr[ra] = addr;
                        r->nip += 4;
                        goto rti;
                }

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

                // In GUI mode, show error alert
                if (!PrefsFindBool("nogui")) {
                        char str[256];
                        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->nip, r->gpr[24], r->gpr[1]);
                        else
                                sprintf(str, GetString(STR_UNKNOWN_SEGV_ERR), r->nip, r->gpr[24], r->gpr[1], opcode);
                        ErrorAlert(str);
                        QuitEmulator();
                        return;
                }
        }

        // For all other errors, jump into debugger (sort of...)
        if (!ready_for_signals) {
                printf("SIGSEGV\n");
                printf(" sigcontext %p, pt_regs %p\n", sc, r);
                printf(
                        "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                        "  xer %08lx     cr %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->nip, r->link, r->ctr, r->msr,
                        r->xer, r->ccr,
                        r->gpr[0], r->gpr[1], r->gpr[2], r->gpr[3],
                        r->gpr[4], r->gpr[5], r->gpr[6], r->gpr[7],
                        r->gpr[8], r->gpr[9], r->gpr[10], r->gpr[11],
                        r->gpr[12], r->gpr[13], r->gpr[14], r->gpr[15],
                        r->gpr[16], r->gpr[17], r->gpr[18], r->gpr[19],
                        r->gpr[20], r->gpr[21], r->gpr[22], r->gpr[23],
                        r->gpr[24], r->gpr[25], r->gpr[26], r->gpr[27],
                        r->gpr[28], r->gpr[29], r->gpr[30], r->gpr[31]);
                exit(1);
                QuitEmulator();
                return;
        } else {
                // We crashed. Save registers, tell tick thread and loop forever
                sigsegv_regs = *(sigregs *)r;
                emul_thread_fatal = true;
                for (;;) ;
        }
rti:;
}


/*
 *  SIGILL handler
 */

static void sigill_handler(int sig, sigcontext_struct *sc)
{
        pt_regs *r = sc->regs;
        char str[256];

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

                // Get opcode and divide into fields
                uint32 opcode = *((uint32 *)r->nip);
                uint32 primop = opcode >> 26;
                uint32 exop = (opcode >> 1) & 0x3ff;
                uint32 ra = (opcode >> 16) & 0x1f;
                uint32 rb = (opcode >> 11) & 0x1f;
                uint32 rd = (opcode >> 21) & 0x1f;
                int32 imm = (int16)(opcode & 0xffff);

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

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

                                        case 210:       // mtsr
                                        case 242:       // mtsrin
                                        case 306:       // tlbie
                                                r->nip += 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->nip += 4;
                                                                goto rti;
                                                        case 25:        // SDR1
                                                                r->gpr[rd] = 0xdead001f;
                                                                r->nip += 4;
                                                                goto rti;
                                                        case 287:       // PVR
                                                                r->gpr[rd] = PVR;
                                                                r->nip += 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->nip += 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->nip, r->gpr[24], r->gpr[1], opcode);
                        ErrorAlert(str);
                        QuitEmulator();
                        return;
                }
        }

        // For all other errors, jump into debugger (sort of...)
        if (!ready_for_signals) {
                printf("SIGILL\n");
                printf(" sigcontext %p, pt_regs %p\n", sc, r);
                printf(
                        "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                        "  xer %08lx     cr %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->nip, r->link, r->ctr, r->msr,
                        r->xer, r->ccr,
                        r->gpr[0], r->gpr[1], r->gpr[2], r->gpr[3],
                        r->gpr[4], r->gpr[5], r->gpr[6], r->gpr[7],
                        r->gpr[8], r->gpr[9], r->gpr[10], r->gpr[11],
                        r->gpr[12], r->gpr[13], r->gpr[14], r->gpr[15],
                        r->gpr[16], r->gpr[17], r->gpr[18], r->gpr[19],
                        r->gpr[20], r->gpr[21], r->gpr[22], r->gpr[23],
                        r->gpr[24], r->gpr[25], r->gpr[26], r->gpr[27],
                        r->gpr[28], r->gpr[29], r->gpr[30], r->gpr[31]);
                exit(1);
                QuitEmulator();
                return;
        } else {
                // We crashed. Save registers, tell tick thread and loop forever
                sigsegv_regs = *(sigregs *)r;
                emul_thread_fatal = true;
                for (;;) ;
        }
rti:;
}
#endif


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

bool SheepMem::Init(void)
{
        const int page_size = getpagesize();

        // Allocate SheepShaver globals
        if (vm_acquire_fixed((char *)base, size) < 0)
                return false;

        // Allocate page with all bits set to 0
        zero_page = base + size;
        if (vm_acquire_fixed((char *)zero_page, page_size) < 0)
                return false;
        memset((char *)zero_page, 0, page_size);
        if (vm_protect((char *)zero_page, page_size, VM_PAGE_READ) < 0)
                return false;

#if EMULATED_PPC
        // Allocate alternate stack for PowerPC interrupt routine
        sig_stack = zero_page + page_size;
        if (vm_acquire_fixed((char *)sig_stack, SIG_STACK_SIZE) < 0)
                return false;
#endif

        top = base + size;
        return true;
}

void SheepMem::Exit(void)
{
        if (top) {
                const int page_size = getpagesize();

                // Delete SheepShaver globals
                vm_release((void *)base, size);

                // Delete zero page
                vm_release((void *)zero_page, page_size);

#if EMULATED_PPC
                // Delete alternate stack for PowerPC interrupt routine
                vm_release((void *)sig_stack, SIG_STACK_SIZE);
#endif
        }
}


/*
 *  Display alert
 */

#ifdef ENABLE_GTK
static void dl_destroyed(void)
{
        gtk_main_quit();
}

static void dl_quit(GtkWidget *dialog)
{
        gtk_widget_destroy(dialog);
}

void display_alert(int title_id, int prefix_id, int button_id, const char *text)
{
        char str[256];
        sprintf(str, GetString(prefix_id), text);

        GtkWidget *dialog = gtk_dialog_new();
        gtk_window_set_title(GTK_WINDOW(dialog), GetString(title_id));
        gtk_container_border_width(GTK_CONTAINER(dialog), 5);
        gtk_widget_set_uposition(GTK_WIDGET(dialog), 100, 150);
        gtk_signal_connect(GTK_OBJECT(dialog), "destroy", GTK_SIGNAL_FUNC(dl_destroyed), NULL);

        GtkWidget *label = gtk_label_new(str);
        gtk_widget_show(label);
        gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dialog)->vbox), label, TRUE, TRUE, 0);

        GtkWidget *button = gtk_button_new_with_label(GetString(button_id));
        gtk_widget_show(button);
        gtk_signal_connect_object(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(dl_quit), GTK_OBJECT(dialog));
        gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dialog)->action_area), button, FALSE, FALSE, 0);
        GTK_WIDGET_SET_FLAGS(button, GTK_CAN_DEFAULT);
        gtk_widget_grab_default(button);
        gtk_widget_show(dialog);

        gtk_main();
}
#endif


/*
 *  Display error alert
 */

void ErrorAlert(const char *text)
{
#ifdef ENABLE_GTK
        if (PrefsFindBool("nogui") || x_display == NULL) {
                printf(GetString(STR_SHELL_ERROR_PREFIX), text);
                return;
        }
        VideoQuitFullScreen();
        display_alert(STR_ERROR_ALERT_TITLE, STR_GUI_ERROR_PREFIX, STR_QUIT_BUTTON, text);
#else
        printf(GetString(STR_SHELL_ERROR_PREFIX), text);
#endif
}


/*
 *  Display warning alert
 */

void WarningAlert(const char *text)
{
#ifdef ENABLE_GTK
        if (PrefsFindBool("nogui") || x_display == NULL) {
                printf(GetString(STR_SHELL_WARNING_PREFIX), text);
                return;
        }
        display_alert(STR_WARNING_ALERT_TITLE, STR_GUI_WARNING_PREFIX, STR_OK_BUTTON, text);
#else
        printf(GetString(STR_SHELL_WARNING_PREFIX), text);
#endif
}


/*
 *  Display choice alert
 */

bool ChoiceAlert(const char *text, const char *pos, const char *neg)
{
        printf(GetString(STR_SHELL_WARNING_PREFIX), text);
        return false;   //!!
}
Revision:	1.21
Committed:	2003-12-31T18:16:55Z (20 years, 10 months ago) by gbeauche
Branch:	MAIN
Changes since 1.20:	+3 -0 lines
Log Message:	Add fast X11 display locking routines based on spinlocks, or on pthreads in the worst case. Optimize out GetScrap() case when we already own the selection. i.e. make it smoother. Use our own XDisplay{Un,}Lock() routines.