scc

commit 50823e3a5e52629d8eee8980583e1387aeb75d86
parent 0714d6c83087281c17643f2c48ab1568f95f8320
Author: Naveen Narayanan <zerous@simple-cc.org>
Date:   Sat,  2 Oct 2021 03:24:29 +0200

libc: Fix bug in strchr.s for amd64

Reset ZF flag after subq instruction as the sub operation sets ZF flag
when the length of string s is 0. This busts the jump logic used
after scan string instruction.

Diffstat:
M
src/libc/arch/amd64/strchr.s
 | 
2
++

1 file changed, 2 insertions(+), 0 deletions(-)
diff --git a/src/libc/arch/amd64/strchr.s b/src/libc/arch/amd64/strchr.s
@@ -15,6 +15,8 @@ strchr:
 	leaq	-1(%rdi),%rcx
 	subq	%r8,%rcx
 
+	cmp     %rdi,%rsi       /* set ZF to 0 */
+
 	movq	%r8,%rdi
 	movb	%sil,%al
 	repne