[PATCH 2/2] armv8/cache.S: Triple with single instruction

Pierre-Clément Tosi ptosi at google.com
Fri Aug 27 18:04:10 CEST 2021


Replace the current 2-instruction 2-step tripling code by a
corresponding single instruction leveraging ARMv8-A's "flexible second
operand as a register with optional shift". This has the added benefit
(albeit arguably negligible) of reducing the final code size.

Fix the comment as the tripled cache level is placed in x12, not x0.

Signed-off-by: Pierre-Clément Tosi <ptosi at google.com>
---
 arch/arm/cpu/armv8/cache.S | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm/cpu/armv8/cache.S b/arch/arm/cpu/armv8/cache.S
index aabb3dff61..5051597f6f 100644
--- a/arch/arm/cpu/armv8/cache.S
+++ b/arch/arm/cpu/armv8/cache.S
@@ -80,8 +80,7 @@ ENTRY(__asm_dcache_all)
 	/* x15 <- return address */
 
 loop_level:
-	lsl	x12, x0, #1
-	add	x12, x12, x0		/* x0 <- tripled cache level */
+	add	x12, x0, x0, lsl #1	/* x12 <- tripled cache level */
 	lsr	x12, x10, x12
 	and	x12, x12, #7		/* x12 <- cache type */
 	cmp	x12, #2
-- 
2.33.0.259.gc128427fd7-goog


-- 
Pierre


More information about the U-Boot mailing list