[quake3-commits] r2305 - in trunk/code: asm qcommon
DONOTREPLY at icculus.org
DONOTREPLY at icculus.org
Wed Aug 8 05:34:03 EDT 2012
Author: thilo
Date: 2012-08-08 05:34:03 -0400 (Wed, 08 Aug 2012)
New Revision: 2305
Modified:
trunk/code/asm/vm_x86_64.asm
trunk/code/qcommon/vm_x86.c
Log:
Move argument passing from VM to engine to global variables which allows to get rid of lots of OS specific stuff and also fixes errors that happens when compilers add lots of boilerplate to the DoSyscall() function
Modified: trunk/code/asm/vm_x86_64.asm
===================================================================
--- trunk/code/asm/vm_x86_64.asm 2012-07-23 21:27:17 UTC (rev 2304)
+++ trunk/code/asm/vm_x86_64.asm 2012-08-08 09:34:03 UTC (rev 2305)
@@ -23,26 +23,8 @@
;
; assumes __fastcall calling convention
-DoSyscall PROTO
-
.code
-; Call to static void DoSyscall(int syscallNum, int programStack, int *opStackBase, uint8_t opStackOfs, intptr_t arg)
-
-qsyscall64 PROC
- sub rsp, 28h ; after this esp will be aligned to 16 byte boundary
- mov qword ptr [rsp + 20h], rcx ; 5th parameter "arg" is passed on stack
- mov r9b, bl ; opStackOfs
- mov r8, rdi ; opStackBase
- mov edx, esi ; programStack
- mov ecx, eax ; syscallNum
- mov rax, DoSyscall ; store call address of DoSyscall in rax
- call rax
- add rsp, 28h
- ret
-qsyscall64 ENDP
-
-
; Call to compiled code after setting up the register environment for the VM
; prototype:
; uint8_t qvmcall64(int *programStack, int *opStack, intptr_t *instructionPointers, byte *dataBase);
Modified: trunk/code/qcommon/vm_x86.c
===================================================================
--- trunk/code/qcommon/vm_x86.c 2012-07-23 21:27:17 UTC (rev 2304)
+++ trunk/code/qcommon/vm_x86.c 2012-08-08 09:34:03 UTC (rev 2305)
@@ -390,55 +390,28 @@
/*
=================
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
+int vm_syscallNum;
+int vm_programStack;
+int *vm_opStackBase;
+uint8_t vm_opStackOfs;
+intptr_t vm_arg;
-extern void qsyscall64(void);
-extern uint8_t qvmcall64(int *programStack, int *opStack, intptr_t *instructionPointers, byte *dataBase);
-
-// 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
@@ -446,34 +419,34 @@
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;
}
}
@@ -504,13 +477,8 @@
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.
@@ -522,6 +490,27 @@
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
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