asm_linux_arm.s

Documentation: syscall

     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#include "funcdata.h"
     7
     8//
     9// System calls for arm, Linux
    10//
    11
    12#define SYS__LLSEEK 140  /* from zsysnum_linux_arm.go */
    13// func seek(fd int, offset int64, whence int) (newoffset int64, errno int)
    14// Implemented in assembly to avoid allocation when
    15// taking the address of the return value newoffset.
    16// Underlying system call is
    17//	llseek(int fd, int offhi, int offlo, int64 *result, int whence)
    18TEXT ·seek(SB),NOSPLIT,$0-28
    19	BL	runtime·entersyscall(SB)
    20	MOVW	$SYS__LLSEEK, R7	// syscall entry
    21	MOVW	fd+0(FP), R0
    22	MOVW	offset_hi+8(FP), R1
    23	MOVW	offset_lo+4(FP), R2
    24	MOVW	$newoffset_lo+16(FP), R3
    25	MOVW	whence+12(FP), R4
    26	SWI	$0
    27	MOVW	$0xfffff001, R6
    28	CMP	R6, R0
    29	BLS	okseek
    30	MOVW	$0, R1
    31	MOVW	R1, newoffset_lo+16(FP)
    32	MOVW	R1, newoffset_hi+20(FP)
    33	RSB	$0, R0, R0
    34	MOVW	R0, err+24(FP)
    35	BL	runtime·exitsyscall(SB)
    36	RET
    37okseek:
    38	// system call filled in newoffset already
    39	MOVW	$0, R0
    40	MOVW	R0, err+24(FP)
    41	BL	runtime·exitsyscall(SB)
    42	RET
    43
    44// func rawVforkSyscall(trap, a1, a2, a3 uintptr) (r1, err uintptr)
    45TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-24
    46	MOVW	trap+0(FP), R7	// syscall entry
    47	MOVW	a1+4(FP), R0
    48	MOVW	a2+8(FP), R1
    49	MOVW	a3+12(FP), R2
    50	SWI	$0
    51	MOVW	$0xfffff001, R1
    52	CMP	R1, R0
    53	BLS	ok
    54	MOVW	$-1, R1
    55	MOVW	R1, r1+16(FP)
    56	RSB	$0, R0, R0
    57	MOVW	R0, err+20(FP)
    58	RET
    59ok:
    60	MOVW	R0, r1+16(FP)
    61	MOVW	$0, R0
    62	MOVW	R0, err+20(FP)
    63	RET
    64
    65// func rawSyscallNoError(trap uintptr, a1, a2, a3 uintptr) (r1, r2 uintptr);
    66TEXT ·rawSyscallNoError(SB),NOSPLIT,$0-24
    67	MOVW	trap+0(FP), R7	// syscall entry
    68	MOVW	a1+4(FP), R0
    69	MOVW	a2+8(FP), R1
    70	MOVW	a3+12(FP), R2
    71	SWI	$0
    72	MOVW	R0, r1+16(FP)
    73	MOVW	$0, R0
    74	MOVW	R0, r2+20(FP)
    75	RET
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