Module Name: src
Committed By: thorpej
Date: Wed Jul 7 02:44:04 UTC 2021
Modified Files:
src/sys/arch/alpha/alpha: locore.s
Log Message:
Re-arrange alpha_copystr() so that the the error/unlikely cases are forward
branches (which will be predicted as not-taken), and that the likely cases
are fall-through, with the exception of the loop branch (which is a backward
branch, and thus will be predicted as taken).
To generate a diff of this commit:
cvs rdiff -u -r1.137 -r1.138 src/sys/arch/alpha/alpha/locore.s
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/alpha/alpha/locore.s
diff -u src/sys/arch/alpha/alpha/locore.s:1.137 src/sys/arch/alpha/alpha/locore.s:1.138
--- src/sys/arch/alpha/alpha/locore.s:1.137 Sun May 23 01:00:53 2021
+++ src/sys/arch/alpha/alpha/locore.s Wed Jul 7 02:44:04 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: locore.s,v 1.137 2021/05/23 01:00:53 thorpej Exp $ */
+/* $NetBSD: locore.s,v 1.138 2021/07/07 02:44:04 thorpej Exp $ */
/*-
* Copyright (c) 1999, 2000, 2019 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
#include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.137 2021/05/23 01:00:53 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.138 2021/07/07 02:44:04 thorpej Exp $");
#include "assym.h"
@@ -900,15 +900,13 @@ LEAF_NOPROFILE(lwp_trampoline, 0)
/**************************************************************************/
/*
- * XXX XXX XXX: Should be removed?
+ * alpha_copystr(const void *from, void *to, size_t len, size_t *donep)
*/
LEAF(alpha_copystr, 4)
LDGP(pv)
mov a2, t0 /* t0 = i = len */
- bne a2, 1f /* if (len != 0), proceed */
- ldiq t1, 1 /* else bail */
- br zero, 2f
+ beq a2, 5f /* if (len == 0), bail */
1: ldq_u t1, 0(a0) /* t1 = *from */
extbl t1, a0, t1
@@ -927,13 +925,16 @@ LEAF(alpha_copystr, 4)
2: beq a3, 3f /* if (lenp != NULL) */
subl t0, a2, t0 /* *lenp = (i - len) */
stq t0, 0(a3)
-3: beq t1, 4f /* *from == '\0'; leave quietly */
+3: bne t1, 4f /* *from != '\0'; leave in a huff */
- ldiq v0, ENAMETOOLONG /* *from != '\0'; error. */
+ mov zero, v0 /* return 0. */
RET
-4: mov zero, v0 /* return 0. */
+4: ldiq v0, ENAMETOOLONG
RET
+
+5: ldiq t1, 1 /* fool the test above... */
+ br zero, 2b
END(alpha_copystr)
NESTED(copyinstr, 4, 16, ra, IM_RA|IM_S0, 0)
