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#include "textflag.h"
6
7// Set the x_crosscall2_ptr C function pointer variable point to crosscall2.
8// It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2
9// Use a local trampoline, to avoid taking the address of a dynamically exported
10// function.
11TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
12 MOVL _crosscall2_ptr(SB), AX
13 MOVL $crosscall2_trampoline<>(SB), BX
14 MOVL BX, (AX)
15 RET
16
17TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0
18 JMP crosscall2(SB)
19
20// Called by C code generated by cmd/cgo.
21// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
22// Saves C callee-saved registers and calls cgocallback with three arguments.
23// fn is the PC of a func(a unsafe.Pointer) function.
24TEXT crosscall2(SB),NOSPLIT,$28-16
25 MOVL BP, 24(SP)
26 MOVL BX, 20(SP)
27 MOVL SI, 16(SP)
28 MOVL DI, 12(SP)
29
30 MOVL ctxt+12(FP), AX
31 MOVL AX, 8(SP)
32 MOVL a+4(FP), AX
33 MOVL AX, 4(SP)
34 MOVL fn+0(FP), AX
35 MOVL AX, 0(SP)
36 CALL runtime·cgocallback(SB)
37
38 MOVL 12(SP), DI
39 MOVL 16(SP), SI
40 MOVL 20(SP), BX
41 MOVL 24(SP), BP
42 RET
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