Bug 50408

Summary: [patch] Accelerate CAIRO_BITSWAP8 on 64 bit machines
Product: cairo Reporter: Homer Hsing <dongsheng.xing>
Component: generalAssignee: Carl Worth <cworth>
Status: RESOLVED MOVED QA Contact: cairo-bugs mailing list <cairo-bugs>
Severity: normal    
Priority: medium    
Version: 1.12.2   
Hardware: All   
OS: All   
Whiteboard:
i915 platform: i915 features:

Description Homer Hsing 2012-05-27 22:27:28 UTC 
Hi, CAIRO_BITSWAP8 costs seven operations on a 32 bit machine, but it can be done with only four operations on 64 bit machines. This patch accelerates CAIRO_BITSWAP8.

diff --git a/src/cairoint.h b/src/cairoint.h
index 2c9f2dd..7e62d86 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -169,7 +169,11 @@ do {                                       \
  * Devised by Sean Anderson, July 13, 2001.
  * Source: http://graphics.stanford.edu/~seander/bithacks.html#ReverseByteWith32Bits
  */
+#if (SIZEOF_VOID_P >= 8)
+#define CAIRO_BITSWAP8(c) ((((c) * 0x80200802LLU & 0x884422110LLU) * 0x101010101LLU) >> 32)
+#else
 #define CAIRO_BITSWAP8(c) ((((c) * 0x0802LU & 0x22110LU) | ((c) * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16)
+#endif
 
 /* Return the number of 1 bits in mask.
  *
Comment 1 GitLab Migration User 2018-08-25 13:29:17 UTC 
-- GitLab Migration Automatic Message --

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