[PATCH 09/20] powerpc/8xx: Optimize verification in FixupDAR

From: Christophe Leroy
Date: Fri Aug 08 2014 - 03:07:02 EST


By XORing the upper part of the instruction code, we get a value that can
directly be verified with the second test and we can remove the first test.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>

---
arch/powerpc/kernel/head_8xx.S | 6 ++----
1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index e5a250c..5037420 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -542,10 +542,8 @@ FixupDAR:/* Entry point for dcbx workaround. */
/* Check if it really is a dcbx instruction. */
/* dcbt and dcbtst does not generate DTLB Misses/Errors,
* no need to include them here */
- srwi r10, r11, 26 /* check if major OP code is 31 */
- cmpwi cr0, r10, 31
- bne- 141f
- rlwinm r10, r11, 0, 21, 30
+ xoris r10, r11, 0x7c00 /* check if major OP code is 31 */
+ rlwinm r10, r10, 0, 21, 5
cmpwi cr0, r10, 2028 /* Is dcbz? */
beq+ 142f
cmpwi cr0, r10, 940 /* Is dcbi? */
--
1.7.1

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