[PATCH v3 10/21] powerpc/8xx: Duplicate two insns instead of branching
From: Christophe Leroy <hidden>
Date: 2014-09-17 16:40:19
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Branching takes two cycles on MPC8xx. Lets duplicate the two instructions and avoid the branching. Signed-off-by: Christophe Leroy <redacted> --- Changes in v2: - None Changes in v3: - None arch/powerpc/kernel/head_8xx.S | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 5037420..4a49ff3 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S@@ -638,9 +638,11 @@ modified_instr: /* special handling for r10,r11 since these are modified already */ 153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */ - b 155f + add r10, r10, r11 /* add it */ + mfctr r11 /* restore r11 */ + b 151b 154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */ -155: add r10, r10, r11 /* add it */ + add r10, r10, r11 /* add it */ mfctr r11 /* restore r11 */ b 151b #endif
--
1.7.1