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// Copyright 2014 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.
// +build gc
#include "textflag.h"
TEXT ·RewindAndSetgid(SB),NOSPLIT|NOFRAME,$0-0
// Save link register
MOVD R30, R9
// Rewind stack pointer so anything that happens on the stack
// will clobber the test pattern created by the caller
ADD $(1024 * 8), RSP
// Ask signaller to setgid
MOVD $·Baton(SB), R0
MOVD $1, R1
storeloop:
LDAXRW (R0), R2
STLXRW R1, (R0), R3
CBNZ R3, storeloop
// Wait for setgid completion
MOVW $0, R1
MOVW $0, R2
loop:
LDAXRW (R0), R3
CMPW R1, R3
BNE loop
STLXRW R2, (R0), R3
CBNZ R3, loop
// Restore stack
SUB $(1024 * 8), RSP
MOVD R9, R30
RET
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