From 7bf6057b962016eee57bc76295f80a26f90172f7 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Wed, 23 Aug 2017 16:54:36 +0200 Subject: powerpc/32: optimise memset() There is no need to extend the set value to an int when the length is lower than 4 as in that case we only do byte stores. We can therefore immediately branch to the part handling it. By separating it from the normal case, we are able to eliminate a few actions on the destination pointer. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/lib/copy_32.S | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'arch/powerpc/lib') diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S index a3ffeac69eca..05aaee20590f 100644 --- a/arch/powerpc/lib/copy_32.S +++ b/arch/powerpc/lib/copy_32.S @@ -91,17 +91,17 @@ EXPORT_SYMBOL(memset16) * replaced by a nop once cache is active. This is done in machine_init() */ _GLOBAL(memset) + cmplwi 0,r5,4 + blt 7f + rlwimi r4,r4,8,16,23 rlwimi r4,r4,16,0,15 - addi r6,r3,-4 - cmplwi 0,r5,4 - blt 7f - stwu r4,4(r6) + stw r4,0(r3) beqlr - andi. r0,r6,3 + andi. r0,r3,3 add r5,r0,r5 - subf r6,r0,r6 + subf r6,r0,r3 cmplwi 0,r4,0 bne 2f /* Use normal procedure if r4 is not zero */ _GLOBAL(memset_nocache_branch) @@ -132,13 +132,20 @@ _GLOBAL(memset_nocache_branch) 1: stwu r4,4(r6) bdnz 1b 6: andi. r5,r5,3 -7: cmpwi 0,r5,0 beqlr mtctr r5 addi r6,r6,3 8: stbu r4,1(r6) bdnz 8b blr + +7: cmpwi 0,r5,0 + beqlr + mtctr r5 + addi r6,r3,-1 +9: stbu r4,1(r6) + bdnz 9b + blr EXPORT_SYMBOL(memset) /* -- cgit