[Pixman] [PATCH 02/14] ARMv6: Minor optimisation

Ben Avison bavison at riscosopen.org
Tue Oct 1 16:00:22 PDT 2013


This knocks off one instruction per row. The effect is probably too small to
be measurable, but might as well be included. The second occurrence of this
sequence doesn't actually benefit at all, but is changed for consistency.
---
 pixman/pixman-arm-simd-asm.h |   11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/pixman/pixman-arm-simd-asm.h b/pixman/pixman-arm-simd-asm.h
index 74400c1..3a2c250 100644
--- a/pixman/pixman-arm-simd-asm.h
+++ b/pixman/pixman-arm-simd-asm.h
@@ -741,12 +741,9 @@ fname:
         preload_leading_step1  mask_bpp, WK2, MASK
         preload_leading_step1  dst_r_bpp, WK3, DST
         
-        tst     DST, #15
+        ands    WK0, DST, #15
         beq     154f
-        rsb     WK0, DST, #0 /* bits 0-3 = number of leading bytes until destination aligned */
-  .if (src_bpp != 0 && src_bpp != 2*dst_w_bpp) || (mask_bpp != 0 && mask_bpp != 2*dst_w_bpp)
-        PF  and,    WK0, WK0, #15
-  .endif
+        rsb     WK0, WK0, #16 /* bits 0-3 = number of leading bytes until destination aligned */
 
         preload_leading_step2  src_bpp, src_bpp_shift, WK1, SRC
         preload_leading_step2  mask_bpp, mask_bpp_shift, WK2, MASK
@@ -787,9 +784,9 @@ fname:
         preload_line 0, dst_r_bpp, dst_bpp_shift, DST
         
         sub     X, X, #128/dst_w_bpp     /* simplifies inner loop termination */
-        tst     DST, #15
+        ands    WK0, DST, #15
         beq     164f
-        rsb     WK0, DST, #0 /* bits 0-3 = number of leading bytes until destination aligned */
+        rsb     WK0, WK0, #16 /* bits 0-3 = number of leading bytes until destination aligned */
         
         leading_15bytes  process_head, process_tail
         
-- 
1.7.10.4



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