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https://github.com/UberGames/ioef.git
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* More robust x86 vm entrypoint/callback assembly (Tron)
This commit is contained in:
Tim Angus
parent
d781a25157
commit
1af6eb9592
1 changed files with 74 additions and 96 deletions
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@ -53,7 +53,6 @@ static void VM_Destroy_Compiled(vm_t* self);
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*/
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// TTimo: initialised the statics, this fixes a crash when entering a compiled VM
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static byte *buf = NULL;
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static byte *jused = NULL;
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static int compiledOfs = 0;
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@ -71,9 +70,6 @@ int _ftol( float );
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static int ftolPtr = (int)_ftol;
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#endif
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void AsmCall( void );
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static int asmCallPtr = (int)AsmCall;
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#else // _MSC_VER
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#if defined( FTOL_PTR )
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@ -88,10 +84,11 @@ int qftol0F7F( void );
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static int ftolPtr = (int)qftol0F7F;
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#endif // FTOL_PTR
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void doAsmCall( void );
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static int asmCallPtr = (int)doAsmCall;
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#endif
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void AsmCall(void);
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static void (*const asmCallPtr)(void) = AsmCall;
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static int callMask = 0;
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@ -124,7 +121,7 @@ vm_t* savedVM;
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__asm {
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mov eax, dword ptr [edi]
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sub edi, 4
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or eax,eax
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test eax,eax
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jl systemCall
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// calling another vm function
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shl eax,2
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@ -137,8 +134,7 @@ systemCall:
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// convert negative num to system call number
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// and store right before the first arg
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neg eax
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dec eax
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not eax
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push ebp
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mov ebp, esp
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@ -180,68 +176,58 @@ _asm {
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#else //!_MSC_VER
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#if defined(__MINGW32__) || defined(MACOS_X) // _ is prepended to compiled symbols
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#define CMANG(sym) "_"#sym
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# define CMANG(sym) "_"#sym
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#else
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#define CMANG(sym) #sym
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# define CMANG(sym) #sym
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#endif
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static int callProgramStack;
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static int *callOpStack;
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static int callSyscallNum;
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void callAsmCall(void)
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static void __attribute__((cdecl, used)) CallAsmCall(int const syscallNum,
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int const programStack, int* const opStack)
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{
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vm_t *savedVM;
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int *callOpStack2;
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savedVM = currentVM;
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callOpStack2 = callOpStack;
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vm_t *const vm = currentVM;
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intptr_t *const data = (intptr_t*)(vm->dataBase + programStack + 4);
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// save the stack to allow recursive VM entry
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currentVM->programStack = callProgramStack - 4;
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*(int *)((byte *)currentVM->dataBase + callProgramStack + 4) = callSyscallNum;
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//VM_LogSyscalls((int *)((byte *)currentVM->dataBase + callProgramStack + 4) );
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*(callOpStack2+1) = currentVM->systemCall( (intptr_t *)((byte *)currentVM->dataBase + callProgramStack + 4) );
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vm->programStack = programStack - 4;
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*data = syscallNum;
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opStack[1] = vm->systemCall(data);
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currentVM = savedVM;
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currentVM = vm;
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}
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// Note the C space function AsmCall is never actually called, and is in fact
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// arbitrarily named (though this is not true for the MSC version). When a vm
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// makes a system call, control jumps straight to the doAsmCall label.
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void AsmCall( void ) {
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__asm__( CMANG(doAsmCall) ": \n\t" \
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" movl (%%edi),%%eax \n\t" \
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" subl $4,%%edi \n\t" \
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" orl %%eax,%%eax \n\t" \
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" jl systemCall \n\t" \
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" shll $2,%%eax \n\t" \
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" addl %3,%%eax \n\t" \
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" call *(%%eax) \n\t" \
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" movl (%%edi),%%eax \n\t" \
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" andl " CMANG(callMask) ", %%eax \n\t" \
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" jmp doret \n\t" \
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"systemCall: \n\t" \
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" negl %%eax \n\t" \
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" decl %%eax \n\t" \
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" movl %%eax,%0 \n\t" \
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" movl %%esi,%1 \n\t" \
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" movl %%edi,%2 \n\t" \
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" pushl %%ecx \n\t" \
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" pushl %%esi \n\t" \
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" pushl %%edi \n\t" \
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" call " CMANG(callAsmCall) " \n\t" \
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" popl %%edi \n\t" \
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" popl %%esi \n\t" \
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" popl %%ecx \n\t" \
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" addl $4,%%edi \n\t" \
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"doret: \n\t" \
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" ret \n\t" \
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: "=rm" (callSyscallNum), "=rm" (callProgramStack), "=rm" (callOpStack) \
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: "m" (instructionPointers) \
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: "ax", "di", "si", "cx" \
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);
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}
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__asm__(
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".text\n\t"
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".p2align 4,,15\n\t"
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#if defined __ELF__
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".type " CMANG(AsmCall) ", @function\n"
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#endif
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CMANG(AsmCall) ":\n\t"
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"movl (%edi), %eax\n\t"
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"subl $4, %edi\n\t"
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"testl %eax, %eax\n\t"
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"jl 0f\n\t"
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"shll $2, %eax\n\t"
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"addl " CMANG(instructionPointers) ", %eax\n\t"
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"call *(%eax)\n\t"
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"movl (%edi), %eax\n\t"
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"andl " CMANG(callMask) ", %eax\n\t"
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"ret\n"
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"0:\n\t" // system call
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"notl %eax\n\t"
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"pushl %ecx\n\t"
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"pushl %edi\n\t" // opStack
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"pushl %esi\n\t" // programStack
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"pushl %eax\n\t" // syscallNum
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"call " CMANG(CallAsmCall) "\n\t"
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"addl $12, %esp\n\t"
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"popl %ecx\n\t"
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"addl $4, %edi\n\t"
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"ret\n\t"
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#if defined __ELF__
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".size " CMANG(AsmCall)", .-" CMANG(AsmCall)
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#endif
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);
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#endif
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static int Constant4( void ) {
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@ -1142,7 +1128,6 @@ int VM_CallCompiled( vm_t *vm, int *args ) {
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int programStack;
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int stackOnEntry;
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byte *image;
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void *entryPoint;
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void *opStack;
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int *oldInstructionPointers;
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@ -1181,45 +1166,38 @@ int VM_CallCompiled( vm_t *vm, int *args ) {
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*(int *)&image[ programStack ] = -1; // will terminate the loop on return
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// off we go into generated code...
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entryPoint = vm->codeBase;
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opStack = &stack;
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#ifdef _MSC_VER
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__asm {
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pushad
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mov esi, programStack;
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mov edi, opStack
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call entryPoint
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mov programStack, esi
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mov opStack, edi
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popad
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}
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#else
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{
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static int memProgramStack;
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static void *memOpStack;
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static void *memEntryPoint;
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#ifdef _MSC_VER
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void *entryPoint = vm->codeBase;
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memProgramStack = programStack;
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memOpStack = opStack;
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memEntryPoint = entryPoint;
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__asm__(" pushal \n" \
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" movl %0,%%esi \n" \
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" movl %1,%%edi \n" \
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" call *%2 \n" \
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" movl %%esi,%0 \n" \
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" movl %%edi,%1 \n" \
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" popal \n" \
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: "=m" (memProgramStack), "=m" (memOpStack) \
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: "m" (memEntryPoint), "m" (memProgramStack), "m" (memOpStack) \
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: "si", "di" \
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__asm {
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pushad
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mov esi, programStack
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mov edi, opStack
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call entryPoint
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mov programStack, esi
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mov opStack, edi
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popad
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}
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#else
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/* These registers are used as scratch registers and are destroyed after the
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* call. Do not use clobber, so they can be used as input for the asm. */
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unsigned eax;
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unsigned ebx;
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unsigned ecx;
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unsigned edx;
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__asm__ volatile(
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"call *%6"
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: "+S" (programStack), "+D" (opStack),
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"=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
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: "mr" (vm->codeBase)
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: "cc", "memory"
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);
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programStack = memProgramStack;
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opStack = memOpStack;
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}
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#endif
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}
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if ( opStack != &stack[1] ) {
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Com_Error( ERR_DROP, "opStack corrupted in compiled code" );
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