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Diffstat (limited to '')
| -rw-r--r-- | src/runtime/cgo/asm_amd64.s | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/src/runtime/cgo/asm_amd64.s b/src/runtime/cgo/asm_amd64.s new file mode 100644 index 0000000..6bf1363 --- /dev/null +++ b/src/runtime/cgo/asm_amd64.s @@ -0,0 +1,47 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "textflag.h" +#include "abi_amd64.h" + +// Set the x_crosscall2_ptr C function pointer variable point to crosscall2. +// It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2 +// Use a local trampoline, to avoid taking the address of a dynamically exported +// function. +TEXT ·set_crosscall2(SB),NOSPLIT,$0-0 + MOVQ _crosscall2_ptr(SB), AX + MOVQ $crosscall2_trampoline<>(SB), BX + MOVQ BX, (AX) + RET + +TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0 + JMP crosscall2(SB) + +// Called by C code generated by cmd/cgo. +// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr) +// Saves C callee-saved registers and calls cgocallback with three arguments. +// fn is the PC of a func(a unsafe.Pointer) function. +// This signature is known to SWIG, so we can't change it. +TEXT crosscall2(SB),NOSPLIT,$0-0 + PUSH_REGS_HOST_TO_ABI0() + + // Make room for arguments to cgocallback. + ADJSP $0x18 +#ifndef GOOS_windows + MOVQ DI, 0x0(SP) /* fn */ + MOVQ SI, 0x8(SP) /* arg */ + // Skip n in DX. + MOVQ CX, 0x10(SP) /* ctxt */ +#else + MOVQ CX, 0x0(SP) /* fn */ + MOVQ DX, 0x8(SP) /* arg */ + // Skip n in R8. + MOVQ R9, 0x10(SP) /* ctxt */ +#endif + + CALL runtime·cgocallback(SB) + + ADJSP $-0x18 + POP_REGS_HOST_TO_ABI0() + RET |