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// Copyright 2015 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"
// bool armcas(int32 *val, int32 old, int32 new)
// Atomically:
// if(*val == old){
// *val = new;
// return 1;
// }else
// return 0;
//
// To implement runtime∕internal∕atomic·cas in sys_$GOOS_arm.s
// using the native instructions, use:
//
// TEXT runtime∕internal∕atomic·cas(SB),NOSPLIT,$0
// B runtime∕internal∕atomic·armcas(SB)
//
TEXT runtime∕internal∕atomic·armcas(SB),NOSPLIT,$0-13
MOVW valptr+0(FP), R1
MOVW old+4(FP), R2
MOVW new+8(FP), R3
casl:
LDREX (R1), R0
CMP R0, R2
BNE casfail
MOVB runtime·goarm(SB), R11
CMP $7, R11
BLT 2(PC)
WORD $0xf57ff05a // dmb ishst
STREX R3, (R1), R0
CMP $0, R0
BNE casl
MOVW $1, R0
MOVB runtime·goarm(SB), R11
CMP $7, R11
BLT 2(PC)
WORD $0xf57ff05b // dmb ish
MOVB R0, ret+12(FP)
RET
casfail:
MOVW $0, R0
MOVB R0, ret+12(FP)
RET
TEXT runtime∕internal∕atomic·Casuintptr(SB),NOSPLIT,$0-13
B runtime∕internal∕atomic·Cas(SB)
TEXT runtime∕internal∕atomic·Loaduintptr(SB),NOSPLIT,$0-8
B runtime∕internal∕atomic·Load(SB)
TEXT runtime∕internal∕atomic·Loaduint(SB),NOSPLIT,$0-8
B runtime∕internal∕atomic·Load(SB)
TEXT runtime∕internal∕atomic·Storeuintptr(SB),NOSPLIT,$0-8
B runtime∕internal∕atomic·Store(SB)
TEXT runtime∕internal∕atomic·Xadduintptr(SB),NOSPLIT,$0-12
B runtime∕internal∕atomic·Xadd(SB)
TEXT runtime∕internal∕atomic·Loadint64(SB),NOSPLIT,$0-12
B runtime∕internal∕atomic·Load64(SB)
TEXT runtime∕internal∕atomic·Xaddint64(SB),NOSPLIT,$0-20
B runtime∕internal∕atomic·Xadd64(SB)
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