src/syscall/asm_linux_386.s

// 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 "funcdata.h"

//
// System calls for 386, Linux
//

// See ../runtime/sys_linux_386.s for the reason why we always use int 0x80
// instead of the glibc-specific "CALL 0x10(GS)".
#define INVOKE_SYSCALL	INT	$0x80

// func rawVforkSyscall(trap, a1, a2, a3 uintptr) (r1, err uintptr)
TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-24
	MOVL	trap+0(FP), AX	// syscall entry
	MOVL	a1+4(FP), BX
	MOVL	a2+8(FP), CX
	MOVL	a3+12(FP), DX
	POPL	SI // preserve return address
	INVOKE_SYSCALL
	PUSHL	SI
	CMPL	AX, $0xfffff001
	JLS	ok
	MOVL	$-1, r1+16(FP)
	NEGL	AX
	MOVL	AX, err+20(FP)
	RET
ok:
	MOVL	AX, r1+16(FP)
	MOVL	$0, err+20(FP)
	RET

// func rawSyscallNoError(trap uintptr, a1, a2, a3 uintptr) (r1, r2 uintptr);
TEXT ·rawSyscallNoError(SB),NOSPLIT,$0-24
	MOVL	trap+0(FP), AX	// syscall entry
	MOVL	a1+4(FP), BX
	MOVL	a2+8(FP), CX
	MOVL	a3+12(FP), DX
	MOVL	$0, SI
	MOVL	$0, DI
	INVOKE_SYSCALL
	MOVL	AX, r1+16(FP)
	MOVL	DX, r2+20(FP)
	RET

#define SYS_SOCKETCALL 102	/* from zsysnum_linux_386.go */

// func socketcall(call int, a0, a1, a2, a3, a4, a5 uintptr) (n int, err int)
// Kernel interface gets call sub-number and pointer to a0.
TEXT ·socketcall(SB),NOSPLIT,$0-36
	CALL	runtime·entersyscall(SB)
	MOVL	$SYS_SOCKETCALL, AX	// syscall entry
	MOVL	call+0(FP), BX	// socket call number
	LEAL	a0+4(FP), CX	// pointer to call arguments
	MOVL	$0, DX
	MOVL	$0, SI
	MOVL	$0, DI
	INVOKE_SYSCALL
	CMPL	AX, $0xfffff001
	JLS	oksock
	MOVL	$-1, n+28(FP)
	NEGL	AX
	MOVL	AX, err+32(FP)
	CALL	runtime·exitsyscall(SB)
	RET
oksock:
	MOVL	AX, n+28(FP)
	MOVL	$0, err+32(FP)
	CALL	runtime·exitsyscall(SB)
	RET

// func rawsocketcall(call int, a0, a1, a2, a3, a4, a5 uintptr) (n int, err int)
// Kernel interface gets call sub-number and pointer to a0.
TEXT ·rawsocketcall(SB),NOSPLIT,$0-36
	MOVL	$SYS_SOCKETCALL, AX	// syscall entry
	MOVL	call+0(FP), BX	// socket call number
	LEAL		a0+4(FP), CX	// pointer to call arguments
	MOVL	$0, DX
	MOVL	$0, SI
	MOVL	$0, DI
	INVOKE_SYSCALL
	CMPL	AX, $0xfffff001
	JLS	oksock1
	MOVL	$-1, n+28(FP)
	NEGL	AX
	MOVL	AX, err+32(FP)
	RET
oksock1:
	MOVL	AX, n+28(FP)
	MOVL	$0, err+32(FP)
	RET

#define SYS__LLSEEK 140	/* from zsysnum_linux_386.go */
// func Seek(fd int, offset int64, whence int) (newoffset int64, err int)
// Implemented in assembly to avoid allocation when
// taking the address of the return value newoffset.
// Underlying system call is
//	llseek(int fd, int offhi, int offlo, int64 *result, int whence)
TEXT ·seek(SB),NOSPLIT,$0-28
	CALL	runtime·entersyscall(SB)
	MOVL	$SYS__LLSEEK, AX	// syscall entry
	MOVL	fd+0(FP), BX
	MOVL	offset_hi+8(FP), CX
	MOVL	offset_lo+4(FP), DX
	LEAL	newoffset_lo+16(FP), SI	// result pointer
	MOVL	whence+12(FP), DI
	INVOKE_SYSCALL
	CMPL	AX, $0xfffff001
	JLS	okseek
	MOVL	$-1, newoffset_lo+16(FP)
	MOVL	$-1, newoffset_hi+20(FP)
	NEGL	AX
	MOVL	AX, err+24(FP)
	CALL	runtime·exitsyscall(SB)
	RET
okseek:
	// system call filled in newoffset already
	MOVL	$0, err+24(FP)
	CALL	runtime·exitsyscall(SB)
	RET