1 /* -----------------------------------------------------------------------
2 win32.S - Copyright (c) 1996, 1998, 2001, 2002 Red Hat, Inc.
3 Copyright (c) 2001 John Beniton
4 Copyright (c) 2002 Ranjit Mathew
5
6
7 X86 Foreign Function Interface
8
9 Permission is hereby granted, free of charge, to any person obtaining
10 a copy of this software and associated documentation files (the
11 ``Software''), to deal in the Software without restriction, including
12 without limitation the rights to use, copy, modify, merge, publish,
13 distribute, sublicense, and/or sell copies of the Software, and to
14 permit persons to whom the Software is furnished to do so, subject to
15 the following conditions:
16
17 The above copyright notice and this permission notice shall be included
18 in all copies or substantial portions of the Software.
19
20 THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
21 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
23 IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
24 OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
25 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
26 OTHER DEALINGS IN THE SOFTWARE.
27 ----------------------------------------------------------------------- */
28
29 /* theller: almost verbatim translation from gas syntax to MSVC inline
30 assembler code. */
31
32 /* theller: ffi_call_x86 now returns an integer - the difference of the stack
33 pointer before and after the function call. If everything is ok, zero is
34 returned. If stdcall functions are passed the wrong number of arguments,
35 the difference will be nonzero. */
36
37 #include <ffi.h>
38 #include <ffi_common.h>
39
40 __declspec(naked) int
ffi_call_x86(void (* prepfunc)(char *,extended_cif *),extended_cif * ecif,unsigned bytes,unsigned flags,unsigned * rvalue,void (* fn)())41 ffi_call_x86(void (* prepfunc)(char *, extended_cif *), /* 8 */
42 extended_cif *ecif, /* 12 */
43 unsigned bytes, /* 16 */
44 unsigned flags, /* 20 */
45 unsigned *rvalue, /* 24 */
46 void (*fn)()) /* 28 */
47 {
48 _asm {
49 push ebp
50 mov ebp, esp
51
52 push esi // NEW: this register must be preserved across function calls
53 // XXX SAVE ESP NOW!
54 mov esi, esp // save stack pointer before the call
55
56 // Make room for all of the new args.
57 mov ecx, [ebp+16]
58 sub esp, ecx // sub esp, bytes
59
60 mov eax, esp
61
62 // Place all of the ffi_prep_args in position
63 push [ebp + 12] // ecif
64 push eax
65 call [ebp + 8] // prepfunc
66
67 // Return stack to previous state and call the function
68 add esp, 8
69 // FIXME: Align the stack to a 128-bit boundary to avoid
70 // potential performance hits.
71 call [ebp + 28]
72
73 // Load ecif->cif->abi
74 mov ecx, [ebp + 12]
75 mov ecx, [ecx]ecif.cif
76 mov ecx, [ecx]ecif.cif.abi
77
78 cmp ecx, FFI_STDCALL
79 je noclean
80 // STDCALL: Remove the space we pushed for the args
81 mov ecx, [ebp + 16]
82 add esp, ecx
83 // CDECL: Caller has already cleaned the stack
84 noclean:
85 // Check that esp has the same value as before!
86 sub esi, esp
87
88 // Load %ecx with the return type code
89 mov ecx, [ebp + 20]
90
91 // If the return value pointer is NULL, assume no return value.
92 /*
93 Intel asm is weird. We have to explicitely specify 'DWORD PTR' in the nexr instruction,
94 otherwise only one BYTE will be compared (instead of a DWORD)!
95 */
96 cmp DWORD PTR [ebp + 24], 0
97 jne sc_retint
98
99 // Even if there is no space for the return value, we are
100 // obliged to handle floating-point values.
101 cmp ecx, FFI_TYPE_FLOAT
102 jne sc_noretval
103 // fstp %st(0)
104 fstp st(0)
105
106 jmp sc_epilogue
107
108 sc_retint:
109 cmp ecx, FFI_TYPE_INT
110 jne sc_retfloat
111 // # Load %ecx with the pointer to storage for the return value
112 mov ecx, [ebp + 24]
113 mov [ecx + 0], eax
114 jmp sc_epilogue
115
116 sc_retfloat:
117 cmp ecx, FFI_TYPE_FLOAT
118 jne sc_retdouble
119 // Load %ecx with the pointer to storage for the return value
120 mov ecx, [ebp+24]
121 // fstps (%ecx)
122 fstp DWORD PTR [ecx]
123 jmp sc_epilogue
124
125 sc_retdouble:
126 cmp ecx, FFI_TYPE_DOUBLE
127 jne sc_retlongdouble
128 // movl 24(%ebp),%ecx
129 mov ecx, [ebp+24]
130 fstp QWORD PTR [ecx]
131 jmp sc_epilogue
132
133 jmp sc_retlongdouble // avoid warning about unused label
134 sc_retlongdouble:
135 cmp ecx, FFI_TYPE_LONGDOUBLE
136 jne sc_retint64
137 // Load %ecx with the pointer to storage for the return value
138 mov ecx, [ebp+24]
139 // fstpt (%ecx)
140 fstp QWORD PTR [ecx] /* XXX ??? */
141 jmp sc_epilogue
142
143 sc_retint64:
144 cmp ecx, FFI_TYPE_SINT64
145 jne sc_retstruct
146 // Load %ecx with the pointer to storage for the return value
147 mov ecx, [ebp+24]
148 mov [ecx+0], eax
149 mov [ecx+4], edx
150
151 sc_retstruct:
152 // Nothing to do!
153
154 sc_noretval:
155 sc_epilogue:
156 mov eax, esi
157 pop esi // NEW restore: must be preserved across function calls
158 mov esp, ebp
159 pop ebp
160 ret
161 }
162 }
163