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[PATCH] Big-endian fix for memcpy-armv7m.S
- From: Julian Brown <julian at codesourcery dot com>
- To: <newlib at sourceware dot org>
- Date: Fri, 9 Dec 2016 13:54:17 +0000
- Subject: [PATCH] Big-endian fix for memcpy-armv7m.S
- Authentication-results: sourceware.org; auth=none
Hi,
I noticed that memcpy-armv7m.S makes assumptions about little-endian
byte ordering that cause it to get copies with certain sizes/alignments
wrong in big-endian mode. We hit this with a "generic profile" ARMv7
big-endian multilib, but I guess anyone trying to run an M-profile chip
in big-endian mode (if such things exist) could hit the same problem.
I've tested this with (caveat, somewhat experimental!) QEMU patches:
http://lists.nongnu.org/archive/html/qemu-devel/2016-12/msg00972.html
running under the GCC testsuite with an ARMv7 big-endian multilib, and
results show a positive delta for about 15 tests (e.g.
gcc.c-torture/execute/memcpy-2.c, gcc.c-torture/execute/pr65369.c).
OK to apply?
Thanks,
Julian
ChangeLog
* libc/machine/arm/memcpy-armv7m.S (mis_src_copy): Handle
big-endian mode.
commit 45cd47548c95b13eed1eb0121ee15ca63df1b466
Author: Julian Brown <julian@codesourcery.com>
Date: Thu Dec 8 09:56:51 2016 -0800
Big-endian armv7m memcpy fix.
In the case of memcpy-armv7m.S being built for a big-endian multilib
(including armv7 without a specific profile), realignment code made
assumptions about the byte ordering being little-endian.
diff --git a/newlib/libc/machine/arm/memcpy-armv7m.S b/newlib/libc/machine/arm/memcpy-armv7m.S
index 8a70c7d..c8bff36 100644
--- a/newlib/libc/machine/arm/memcpy-armv7m.S
+++ b/newlib/libc/machine/arm/memcpy-armv7m.S
@@ -265,9 +265,17 @@ memcpy:
.macro mis_src_copy shift
1:
+#ifdef __ARM_BIG_ENDIAN
+ lsls r4, r4, \shift
+#else
lsrs r4, r4, \shift
+#endif
ldr r3, [r1], #4
+#ifdef __ARM_BIG_ENDIAN
+ lsrs r5, r3, 32-\shift
+#else
lsls r5, r3, 32-\shift
+#endif
orr r4, r4, r5
str r4, [r0], #4
mov r4, r3