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cebix |
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/* |
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cebix |
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* asm_support.s - Utility functions in assembly language (for native 68k support) |
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cebix |
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* |
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cebix |
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* Basilisk II (C) 1997-2002 Christian Bauer |
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cebix |
1.1 |
* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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.file "asm_support.s" |
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.text |
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.globl _m68k_sync_icache |
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.globl _Start680x0__Fv |
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.globl _SetInterruptFlag__FUi |
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.globl _ClearInterruptFlag__FUi |
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.globl _Execute68k |
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.globl _Execute68kTrap |
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.globl _EmulOpTrampoline |
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.globl _RAMBaseHost |
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.globl _ROMBaseHost |
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.globl _EmulOp__FUsP13M68kRegisters |
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.globl _EmulatedSR |
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.globl _InterruptFlags |
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.globl _TriggerInterrupt__Fv |
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/* |
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* Call m68k_sync_icache() (NetBSD, the version in libm68k is broken) |
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*/ |
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.type _m68k_sync_icache,@function |
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_m68k_sync_icache: |
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movl sp@(8),d1 |
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movl sp@(4),a1 |
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movl #0x80000004,d0 |
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trap #12 |
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rts |
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/* |
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* Jump to Mac ROM, start emulation |
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*/ |
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.type _Start680x0__Fv,@function |
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_Start680x0__Fv: |
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movl _RAMBaseHost,a0 |
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addl #0x8000,a0 |
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movl a0,sp |
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movl _ROMBaseHost,a0 |
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lea a0@(0x2a),a0 |
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jmp a0@ |
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/* |
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* Set/clear interrupt flag (atomically) |
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*/ |
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.type _SetInterruptFlag__FUi,@function |
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_SetInterruptFlag__FUi: |
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movl sp@(4),d0 |
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orl d0,_InterruptFlags |
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rts |
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.type _ClearInterruptFlag__FUi,@function |
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_ClearInterruptFlag__FUi: |
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movl sp@(4),d0 |
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notl d0 |
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andl d0,_InterruptFlags |
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rts |
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/* |
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* Execute 68k subroutine (must be ended with rts) |
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* r->a[7] and r->sr are unused! |
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*/ |
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/* void Execute68k(uint32 addr, M68kRegisters *r); */ |
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.type _Execute68k,@function |
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_Execute68k: movl sp@(4),d0 |Get arguments |
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movl sp@(8),a0 |
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movml d2-d7/a2-a6,sp@- |Save registers |
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movl a0,sp@- |Push pointer to M68kRegisters on stack |
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pea exec68kret |Push return address on stack |
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movl d0,sp@- |Push pointer to 68k routine on stack |
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movml a0@,d0-d7/a0-a6 |Load registers from M68kRegisters |
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rts |Jump into 68k routine |
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exec68kret: movl a6,sp@- |Save a6 |
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movl sp@(4),a6 |Get pointer to M68kRegisters |
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movml d0-d7/a0-a5,a6@ |Save d0-d7/a0-a5 to M68kRegisters |
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movl sp@+,a6@(56) |Save a6 to M68kRegisters |
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addql #4,sp |Remove pointer from stack |
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movml sp@+,d2-d7/a2-a6 |Restore registers |
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rts |
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/* |
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* Execute MacOS 68k trap |
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* r->a[7] and r->sr are unused! |
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*/ |
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/* void Execute68kTrap(uint16 trap, M68kRegisters *r); */ |
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.type _Execute68kTrap,@function |
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_Execute68kTrap: |
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movl sp@(4),d0 |Get arguments |
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movl sp@(8),a0 |
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movml d2-d7/a2-a6,sp@- |Save registers |
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movl a0,sp@- |Push pointer to M68kRegisters on stack |
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movw d0,sp@- |Push trap word on stack |
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subql #8,sp |Create fake A-Line exception frame |
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movml a0@,d0-d7/a0-a6 |Load registers from M68kRegisters |
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movl a2,sp@- |Save a2 and d2 |
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movl d2,sp@- |
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lea exectrapret,a2 |a2 points to return address |
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movw sp@(16),d2 |Load trap word into d2 |
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jmp zpc@(0x28:w)@(10) |Jump into MacOS A-Line handler |
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exectrapret: movl a6,sp@- |Save a6 |
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movl sp@(6),a6 |Get pointer to M68kRegisters |
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movml d0-d7/a0-a5,a6@ |Save d0-d7/a0-a5 to M68kRegisters |
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movl sp@+,a6@(56) |Save a6 to M68kRegisters |
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addql #6,sp |Remove pointer and trap word from stack |
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movml sp@+,d2-d7/a2-a6 |Restore registers |
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rts |
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/* |
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* Call EmulOp() after return from SIGILL handler, registers are pushed on stack |
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*/ |
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.type _EmulOpTrampoline,@function |
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_EmulOpTrampoline: |
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movl sp,a0 |Get pointer to registers |
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movw _EmulatedSR,d0 |Save EmulatedSR, disable interrupts |
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movw d0,sp@- |
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oriw #0x0700,d0 |
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movw d0,_EmulatedSR |
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movl a0,sp@- |Push pointer to registers |
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movl a0@(66),a1 |Get saved PC |
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addql #2,a0@(66) |Skip EMUL_OP opcode |
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movw a1@,sp@- |Push opcode word |
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clrw sp@- |
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jbsr _EmulOp__FUsP13M68kRegisters |
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addql #8,sp |
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movw sp@+,d0 |Restore interrupts, trigger pending interrupt |
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movw d0,_EmulatedSR |
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andiw #0x0700,d0 |
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bne eot1 |
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tstl _InterruptFlags |
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beq eot1 |
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jbsr _TriggerInterrupt__Fv |
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eot1: moveml sp@+,d0-d7/a0-a6 |Restore registers |
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addql #4,sp |Skip saved SP |
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rtr |
