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A ".S" file
I'm trying to build libffi using VC++. Apparently, this is possible (albeit from a command line) but only if I first install Cygwin, MSYS and MinGW.
If all else fails I suppose I'll have to install them but I'd prefer to create a vcproj if possible. I created a suitable project and as it happened, I only encountered one module that won't compile. Unusually, the module is called win32.S and looks something like this:-
Code:
#define LIBFFI_ASM
#include <fficonfig.h>
#include <ffi.h>
#ifdef _MSC_VER
.386
.MODEL FLAT, C
EXTRN ffi_closure_SYSV_inner:NEAR
_TEXT SEGMENT
ffi_call_win32 PROC NEAR,
ffi_prep_args : NEAR PTR DWORD,
ecif : NEAR PTR DWORD,
cif_abi : DWORD,
cif_bytes : DWORD,
cif_flags : DWORD,
rvalue : NEAR PTR DWORD,
fn : NEAR PTR DWORD
;; Make room for all of the new args.
mov ecx, cif_bytes
sub esp, ecx
mov eax, esp
;; Place all of the ffi_prep_args in position
push ecif
push eax
call ffi_prep_args
;; Return stack to previous state and call the function
add esp, 8
;; Handle thiscall and fastcall
cmp cif_abi, 3 ;; FFI_THISCALL
jz do_thiscall
cmp cif_abi, 4 ;; FFI_FASTCALL
jnz do_stdcall
mov ecx, DWORD PTR [esp]
mov edx, DWORD PTR [esp+4]
add esp, 8
jmp do_stdcall
do_thiscall:
mov ecx, DWORD PTR [esp]
add esp, 4
do_stdcall:
call fn
;; cdecl: we restore esp in the epilogue, so there's no need to
;; remove the space we pushed for the args.
;; stdcall: the callee has already cleaned the stack.
;; Load ecx with the return type code
mov ecx, cif_flags
;; If the return value pointer is NULL, assume no return value.
cmp rvalue, 0
jne ca_jumptable
;; Even if there is no space for the return value, we are
;; obliged to handle floating-point values.
cmp ecx, FFI_TYPE_FLOAT
jne ca_epilogue
fstp st(0)
jmp ca_epilogue
ca_jumptable:
jmp [ca_jumpdata + 4 * ecx]
ca_jumpdata:
;; Do not insert anything here between label and jump table.
dd offset ca_epilogue ;; FFI_TYPE_VOID
dd offset ca_retint ;; FFI_TYPE_INT
dd offset ca_retfloat ;; FFI_TYPE_FLOAT
dd offset ca_retdouble ;; FFI_TYPE_DOUBLE
dd offset ca_retlongdouble ;; FFI_TYPE_LONGDOUBLE
dd offset ca_retint8 ;; FFI_TYPE_UINT8
dd offset ca_retint8 ;; FFI_TYPE_SINT8
dd offset ca_retint16 ;; FFI_TYPE_UINT16
dd offset ca_retint16 ;; FFI_TYPE_SINT16
dd offset ca_retint ;; FFI_TYPE_UINT32
dd offset ca_retint ;; FFI_TYPE_SINT32
dd offset ca_retint64 ;; FFI_TYPE_UINT64
dd offset ca_retint64 ;; FFI_TYPE_SINT64
dd offset ca_epilogue ;; FFI_TYPE_STRUCT
dd offset ca_retint ;; FFI_TYPE_POINTER
dd offset ca_retint8 ;; FFI_TYPE_SMALL_STRUCT_1B
dd offset ca_retint16 ;; FFI_TYPE_SMALL_STRUCT_2B
dd offset ca_retint ;; FFI_TYPE_SMALL_STRUCT_4B
ca_retint8:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
mov [ecx + 0], al
jmp ca_epilogue
ca_retint16:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
mov [ecx + 0], ax
jmp ca_epilogue
ca_retint:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
mov [ecx + 0], eax
jmp ca_epilogue
ca_retint64:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
mov [ecx + 0], eax
mov [ecx + 4], edx
jmp ca_epilogue
ca_retfloat:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
fstp DWORD PTR [ecx]
jmp ca_epilogue
ca_retdouble:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
fstp QWORD PTR [ecx]
jmp ca_epilogue
ca_retlongdouble:
;; Load %ecx with the pointer to storage for the return value
mov ecx, rvalue
fstp TBYTE PTR [ecx]
jmp ca_epilogue
ca_epilogue:
;; Epilogue code is autogenerated.
ret
ffi_call_win32 ENDP
// Some more stuff
#endif
I've only shown the first function (there are a few others). As you can see, it's a strange mixture of C and x86 assembly code but the presence of #ifdef _MSC_VER near the top of the file suggests to me that it should be buildable with MSVC. However, VS2005 doesn't seem to like it very much (at least, not from within the IDE).
What would I need to do to compile and link this module? Do I need to pre-process it somehow? Or can it only be built from a command line? Or do I need a more recent version of Visual Studio?
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Re: A ".S" file
My newly found friend, the pre-build step rescued me again. All I needed to do was run this pre-build step:-
cl /EP win32.S > win32.asm
and then I simply compiled the resultant .asm file. :thumb: