runtime: fix madvise for freebsd/amd64

Make use of carry clear condition instead of low or same.

R=minux.ma, jsing, dave
CC=golang-dev
https://golang.org/cl/6844080

diff --git a/src/pkg/runtime/sys_freebsd_amd64.s b/src/pkg/runtime/sys_freebsd_amd64.s
index d66aed107cc5aa1abaad46b475ea52fb68992b0a..6c52dfa15eb4ce705557f5c9f76f6ed2fb83d5d6 100644 (file)
--- a/src/pkg/runtime/sys_freebsd_amd64.s
+++ b/src/pkg/runtime/sys_freebsd_amd64.s
@@ -190,8 +190,7 @@ TEXT runtime·madvise(SB),7,$0
        MOVQ    24(SP), DX
        MOVQ    $75, AX // madvise
        SYSCALL
-       CMPQ    AX, $0xfffffffffffff001
-       JLS     2(PC)
+       JCC     2(PC)
        MOVL    $0xf1, 0xf1  // crash
        RET