diff options
| author | cinap_lenrek <cinap_lenrek@felloff.net> | 2020-05-07 23:27:27 +0200 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@felloff.net> | 2020-05-07 23:27:27 +0200 |
| commit | 04066fe973c628476fbe9eb65bf62a67334987f7 (patch) | |
| tree | c0a9371675c12af3581d60b0a615bc2d48686321 | |
| parent | 7de7414e885c3fa3c52200c49528e1e8da5adcc9 (diff) | |
bcm64: fix kernels cmpswap() function
spectacular bug. cmpswap() had a sign extension bug
using sign extending MOV to load the old compare
value and LDXRW using zero extension while the CMP
instruction compared 64 bit registers.
this caused cmpswap with negative old value always
to fail.
interestingly, libc's version of this function was
fine.
| -rw-r--r-- | sys/src/9/bcm64/l.s | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/src/9/bcm64/l.s b/sys/src/9/bcm64/l.s index 2e7e9ebc1..d6ad02184 100644 --- a/sys/src/9/bcm64/l.s +++ b/sys/src/9/bcm64/l.s @@ -229,8 +229,8 @@ TEXT touser(SB), 1, $-4 TEXT cas(SB), 1, $-4 TEXT cmpswap(SB), 1, $-4 - MOVW ov+8(FP), R1 - MOVW nv+16(FP), R2 + MOVWU ov+8(FP), R1 + MOVWU nv+16(FP), R2 _cas1: LDXRW (R0), R3 CMP R3, R1 |