On the 8xx, load latency is 2 cycles and taking branches also takes
2 cycles. So let's unroll the loop.
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
arch/powerpc/lib/checksum_32.S | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/lib/checksum_32.S b/arch/powerpc/lib/checksum_32.S
index 2e4879c..9c48ee0 100644
--- a/arch/powerpc/lib/checksum_32.S
+++ b/arch/powerpc/lib/checksum_32.S
@@ -75,10 +75,24 @@ _GLOBAL(csum_partial)
srwi. r6,r4,2 /* # words to do */
adde r5,r5,r0
beq 3f
-1: mtctr r6
+1: andi. r6,r6,3 /* Prepare to handle words 4 by 4 */
+ beq 21f
+ mtctr r6
2: lwzu r0,4(r3)
adde r5,r5,r0
bdnz 2b
+21: srwi. r6,r4,4 /* # blocks of 4 words to do */
+ beq 3f
+ mtctr r6
+22: lwzu r0,4(r3)
+ lwzu r6,4(r3)
+ lwzu r7,4(r3)
+ lwzu r8,4(r3)
+ adde r5,r5,r0
+ adde r5,r5,r6
+ adde r5,r5,r7
+ adde r5,r5,r8
+ bdnz 22b
3: andi. r0,r4,2
beq+ 4f
lhz r0,4(r3)
--
2.1.0
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