1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 /*
6 * Apple still insists on underscore prefixes for C function names.
7 */
8 #if defined(__APPLE__)
9 #define EXT(s) _##s
10 #else
11 #define EXT(s) s
12 #endif
13
14 /*
15 * void crosscall_amd64(void (*fn)(void))
16 *
17 * Calling into the 6c tool chain, where all registers are caller save.
18 * Called from standard x86-64 ABI, where %rbx, %rbp, %r12-%r15
19 * are callee-save so they must be saved explicitly.
20 * The standard x86-64 ABI passes the three arguments m, g, fn
21 * in %rdi, %rsi, %rdx.
22 */
23 .globl EXT(crosscall_amd64)
24 EXT(crosscall_amd64):
25 pushq %rbx
26 pushq %rbp
27 pushq %r12
28 pushq %r13
29 pushq %r14
30 pushq %r15
31
32 #if defined(_WIN64)
33 movq %r8, %rdi /* arg of setg_gcc */
34 call *%rdx /* setg_gcc */
35 call *%rcx /* fn */
36 #else
37 movq %rdi, %rbx
38 movq %rdx, %rdi /* arg of setg_gcc */
39 call *%rsi /* setg_gcc */
40 call *%rbx /* fn */
41 #endif
42
43 popq %r15
44 popq %r14
45 popq %r13
46 popq %r12
47 popq %rbp
48 popq %rbx
49 ret
50
51 #ifdef __ELF__
52 .section .note.GNU-stack,"",@progbits
53 #endif
54
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