diff options
Diffstat (limited to 'src/qcommon')
| -rw-r--r-- | src/qcommon/vm_x86.c | 91 |
1 files changed, 40 insertions, 51 deletions
diff --git a/src/qcommon/vm_x86.c b/src/qcommon/vm_x86.c index ef912729..2ef49752 100644 --- a/src/qcommon/vm_x86.c +++ b/src/qcommon/vm_x86.c @@ -391,55 +391,28 @@ static void ErrJump(void) /* ================= DoSyscall -Uses asm to retrieve arguments from registers to work around different calling conventions + +Assembler helper routines will write its arguments directly to global variables so as to +work around different calling conventions ================= */ -#if defined(_MSC_VER) && idx64 - -extern void qsyscall64(void); -extern uint8_t qvmcall64(int *programStack, int *opStack, intptr_t *instructionPointers, byte *dataBase); +int vm_syscallNum; +int vm_programStack; +int *vm_opStackBase; +uint8_t vm_opStackOfs; +intptr_t vm_arg; -// Microsoft does not support inline assembler on x64 platforms. Meh. -void DoSyscall(int syscallNum, int programStack, int *opStackBase, uint8_t opStackOfs, intptr_t arg) -{ -#else static void DoSyscall(void) { - int syscallNum; - int programStack; - int *opStackBase; - uint8_t opStackOfs; - intptr_t arg; -#endif - vm_t *savedVM; -#if defined(_MSC_VER) - #if !idx64 - __asm - { - mov dword ptr syscallNum, eax - mov dword ptr programStack, esi - mov byte ptr opStackOfs, bl - mov dword ptr opStackBase, edi - mov dword ptr arg, ecx - } - #endif -#else - __asm__ volatile( - "" - : "=a" (syscallNum), "=S" (programStack), "=D" (opStackBase), "=b" (opStackOfs), - "=c" (arg) - ); -#endif - // save currentVM so as to allow for recursive VM entry savedVM = currentVM; // modify VM stack pointer for recursive VM entry - currentVM->programStack = programStack - 4; + currentVM->programStack = vm_programStack - 4; - if(syscallNum < 0) + if(vm_syscallNum < 0) { int *data; #if idx64 @@ -447,34 +420,34 @@ static void DoSyscall(void) intptr_t args[16]; #endif - data = (int *) (savedVM->dataBase + programStack + 4); + data = (int *) (savedVM->dataBase + vm_programStack + 4); #if idx64 - args[0] = ~syscallNum; + args[0] = ~vm_syscallNum; for(index = 1; index < ARRAY_LEN(args); index++) args[index] = data[index]; - opStackBase[opStackOfs + 1] = savedVM->systemCall(args); + vm_opStackBase[vm_opStackOfs + 1] = savedVM->systemCall(args); #else - data[0] = ~syscallNum; - opStackBase[opStackOfs + 1] = savedVM->systemCall((intptr_t *) data); + data[0] = ~vm_syscallNum; + vm_opStackBase[vm_opStackOfs + 1] = savedVM->systemCall((intptr_t *) data); #endif } else { - switch(syscallNum) + switch(vm_syscallNum) { case VM_JMP_VIOLATION: ErrJump(); break; case VM_BLOCK_COPY: - if(opStackOfs < 1) + if(vm_opStackOfs < 1) Com_Error(ERR_DROP, "VM_BLOCK_COPY failed due to corrupted opStack"); - VM_BlockCopy(opStackBase[(opStackOfs - 1)], opStackBase[opStackOfs], arg); + VM_BlockCopy(vm_opStackBase[(vm_opStackOfs - 1)], vm_opStackBase[vm_opStackOfs], vm_arg); break; default: - Com_Error(ERR_DROP, "Unknown VM operation %d", syscallNum); + Com_Error(ERR_DROP, "Unknown VM operation %d", vm_syscallNum); break; } } @@ -505,13 +478,8 @@ Call to DoSyscall() int EmitCallDoSyscall(vm_t *vm) { // use edx register to store DoSyscall address -#if defined(_MSC_VER) && idx64 - EmitRexString(0x48, "BA"); // mov edx, qsyscall64 - EmitPtr(qsyscall64); -#else EmitRexString(0x48, "BA"); // mov edx, DoSyscall EmitPtr(DoSyscall); -#endif // Push important registers to stack as we can't really make // any assumptions about calling conventions. @@ -523,6 +491,27 @@ int EmitCallDoSyscall(vm_t *vm) EmitRexString(0x41, "51"); // push r9 #endif + // write arguments to global vars + // syscall number + EmitString("A3"); // mov [0x12345678], eax + EmitPtr(&vm_syscallNum); + // vm_programStack value + EmitString("89 F0"); // mov eax, esi + EmitString("A3"); // mov [0x12345678], eax + EmitPtr(&vm_programStack); + // vm_opStackOfs + EmitString("88 D8"); // mov al, bl + EmitString("A2"); // mov [0x12345678], al + EmitPtr(&vm_opStackOfs); + // vm_opStackBase + EmitRexString(0x48, "89 F8"); // mov eax, edi + EmitRexString(0x48, "A3"); // mov [0x12345678], eax + EmitPtr(&vm_opStackBase); + // vm_arg + EmitString("89 C8"); // mov eax, ecx + EmitString("A3"); // mov [0x12345678], eax + EmitPtr(&vm_arg); + // align the stack pointer to a 16-byte-boundary EmitString("55"); // push ebp EmitRexString(0x48, "89 E5"); // mov ebp, esp |