1 // Copyright 2014 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 // +build gc
6
7 #include "textflag.h"
8
9 TEXT cas<>(SB),NOSPLIT,$0
10 MOVW $0xffff0fc0, R15 // R15 is PC
11
12 TEXT ·RewindAndSetgid(SB),NOSPLIT|NOFRAME,$0-0
13 // Save link register
14 MOVW R14, R4
15
16 // Rewind stack pointer so anything that happens on the stack
17 // will clobber the test pattern created by the caller
18 ADD $(1024 * 8), R13
19
20 // Ask signaller to setgid
21 MOVW $·Baton(SB), R2
22 storeloop:
23 MOVW 0(R2), R0
24 MOVW $1, R1
25 BL cas<>(SB)
26 BCC storeloop
27
28 // Wait for setgid completion
29 loop:
30 MOVW $0, R0
31 MOVW $0, R1
32 BL cas<>(SB)
33 BCC loop
34
35 // Restore stack
36 SUB $(1024 * 8), R13
37
38 MOVW R4, R14
39 RET
40
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