@@ -19,13 +19,41 @@ _GLOBAL(memcmp)
PPC_LCMPI 0,r5,0
beq- 2f
#endif
- mtctr r5
- addi r6,r3,-1
- addi r4,r4,-1
-1: lbzu r3,1(r6)
- lbzu r0,1(r4)
- subf. r3,r0,r3
- bdnzt 2,1b
+ srawi. r7, r5, 2 /* Divide len by 4 */
+ mr r6, r3
+ beq- 3f
+ mtctr r7
+ li r7, 0
+1:
+#ifdef __LITTLE_ENDIAN__
+ lwbrx r3, r6, r7
+ lwbrx r0, r4, r7
+#else
+ lwzx r3, r6, r7
+ lwzx r0, r4, r7
+#endif
+ addi r7, r7, 4
+ subf. r3, r0, r3
+ bdnzt eq, 1b
+ bnelr
+ andi. r5, r5, 3
+ beqlr
+3: cmplwi cr1, r5, 2
+ blt- cr1, 4f
+#ifdef __LITTLE_ENDIAN__
+ lhbrx r3, r6, r7
+ lhbrx r0, r4, r7
+#else
+ lhzx r3, r6, r7
+ lhzx r0, r4, r7
+#endif
+ addi r7, r7, 2
+ subf. r3, r0, r3
+ beqlr cr1
+ bnelr
+4: lbzx r3, r6, r7
+ lbzx r0, r4, r7
+ subf. r3, r0, r3
blr
#ifdef CONFIG_FORTIFY_SOURCE
2: li r3,0
At the time being, memcmp() compares two chunks of memory byte per byte. This patch optimised the comparison by comparing word by word. A small benchmark performed on an 8xx based on the comparison of two chuncks of 512 bytes performed 100000 times gives: Before : 5852274 TB ticks After: 1488638 TB ticks This is almost 4 times faster Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/lib/string_32.S | 42 +++++++++++++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 7 deletions(-)