github.com/google/netstack@v0.0.0-20191123085552-55fcc16cd0eb/sleep/commit_amd64.s (about)

     1  // Copyright 2018 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  #include "textflag.h"
    16  
    17  #define preparingG 1
    18  
    19  // See commit_noasm.go for a description of commitSleep.
    20  //
    21  // func commitSleep(g uintptr, waitingG *uintptr) bool
    22  TEXT ·commitSleep(SB),NOSPLIT,$0-24
    23  	MOVQ waitingG+8(FP), CX
    24  	MOVQ g+0(FP), DX
    25  
    26  	// Store the G in waitingG if it's still preparingG. If it's anything
    27  	// else it means a waker has aborted the sleep.
    28  	MOVQ $preparingG, AX
    29  	LOCK
    30  	CMPXCHGQ DX, 0(CX)
    31  
    32  	SETEQ AX
    33  	MOVB AX, ret+16(FP)
    34  
    35  	RET