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/* -----------------------------------------------------------------------
win32.S - Copyright (c) 1996, 1998, 2001, 2002 Red Hat, Inc.
Copyright (c) 2001 John Beniton
Copyright (c) 2002 Ranjit Mathew
X86 Foreign Function Interface
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
``Software''), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
----------------------------------------------------------------------- */
/* theller: almost verbatim translation from gas syntax to MSVC inline
assembler code. */
/* theller: ffi_call_x86 now returns an integer - the difference of the stack
pointer before and after the function call. If everything is ok, zero is
returned. If stdcall functions are passed the wrong number of arguments,
the difference will be nonzero. */
#include <ffi.h>
#include <ffi_common.h>
__declspec(naked) int
ffi_call_x86(void (* prepfunc)(char *, extended_cif *), /* 8 */
extended_cif *ecif, /* 12 */
unsigned bytes, /* 16 */
unsigned flags, /* 20 */
unsigned *rvalue, /* 24 */
void (*fn)()) /* 28 */
{
_asm {
push ebp
mov ebp, esp
push esi // NEW: this register must be preserved across function calls
// XXX SAVE ESP NOW!
mov esi, esp // save stack pointer before the call
// Make room for all of the new args.
mov ecx, [ebp+16]
sub esp, ecx // sub esp, bytes
mov eax, esp
// Place all of the ffi_prep_args in position
push [ebp + 12] // ecif
push eax
call [ebp + 8] // prepfunc
// Return stack to previous state and call the function
add esp, 8
// FIXME: Align the stack to a 128-bit boundary to avoid
// potential performance hits.
call [ebp + 28]
// Load ecif->cif->abi
mov ecx, [ebp + 12]
mov ecx, [ecx]ecif.cif
mov ecx, [ecx]ecif.cif.abi
cmp ecx, FFI_STDCALL
je noclean
// STDCALL: Remove the space we pushed for the args
mov ecx, [ebp + 16]
add esp, ecx
// CDECL: Caller has already cleaned the stack
noclean:
// Check that esp has the same value as before!
sub esi, esp
// Load %ecx with the return type code
mov ecx, [ebp + 20]
// If the return value pointer is NULL, assume no return value.
/*
Intel asm is weird. We have to explicitely specify 'DWORD PTR' in the nexr instruction,
otherwise only one BYTE will be compared (instead of a DWORD)!
*/
cmp DWORD PTR [ebp + 24], 0
jne sc_retint
// Even if there is no space for the return value, we are
// obliged to handle floating-point values.
cmp ecx, FFI_TYPE_FLOAT
jne sc_noretval
// fstp %st(0)
fstp st(0)
jmp sc_epilogue
sc_retint:
cmp ecx, FFI_TYPE_INT
jne sc_retfloat
// # Load %ecx with the pointer to storage for the return value
mov ecx, [ebp + 24]
mov [ecx + 0], eax
jmp sc_epilogue
sc_retfloat:
cmp ecx, FFI_TYPE_FLOAT
jne sc_retdouble
// Load %ecx with the pointer to storage for the return value
mov ecx, [ebp+24]
// fstps (%ecx)
fstp DWORD PTR [ecx]
jmp sc_epilogue
sc_retdouble:
cmp ecx, FFI_TYPE_DOUBLE
jne sc_retlongdouble
// movl 24(%ebp),%ecx
mov ecx, [ebp+24]
fstp QWORD PTR [ecx]
jmp sc_epilogue
jmp sc_retlongdouble // avoid warning about unused label
sc_retlongdouble:
cmp ecx, FFI_TYPE_LONGDOUBLE
jne sc_retint64
// Load %ecx with the pointer to storage for the return value
mov ecx, [ebp+24]
// fstpt (%ecx)
fstp QWORD PTR [ecx] /* XXX ??? */
jmp sc_epilogue
sc_retint64:
cmp ecx, FFI_TYPE_SINT64
jne sc_retstruct
// Load %ecx with the pointer to storage for the return value
mov ecx, [ebp+24]
mov [ecx+0], eax
mov [ecx+4], edx
sc_retstruct:
// Nothing to do!
sc_noretval:
sc_epilogue:
mov eax, esi
pop esi // NEW restore: must be preserved across function calls
mov esp, ebp
pop ebp
ret
}
}
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