github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sync/race_arm64.s (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // +build race
    16  // +build arm64
    17  
    18  #include "textflag.h"
    19  
    20  // func RaceUncheckedAtomicCompareAndSwapUintptr(ptr *uintptr, old, new uintptr) bool
    21  TEXT ·RaceUncheckedAtomicCompareAndSwapUintptr(SB),NOSPLIT,$0-25
    22  	MOVD ptr+0(FP), R0
    23  	MOVD old+8(FP), R1
    24  	MOVD new+16(FP), R1
    25  again:
    26  	LDAXR (R0), R3
    27  	CMP R1, R3
    28  	BNE ok
    29  	STLXR R2, (R0), R3
    30  	CBNZ R3, again
    31  ok:
    32  	CSET EQ, R0
    33  	MOVB R0, ret+24(FP)
    34  	RET
    35