[Mesa-dev] [PATCH] Replace byte-swapping code with builtins in pack.c

[Jochen Rollwagen]

 From 4cebe50a9bade6717923e104c954f3fad75f71bb Mon Sep 17 00:00:00 2001
From: Jochen Rollwagen <joro-2013 at t-online.de>
Date: Tue, 3 Oct 2017 19:54:10 +0200
Subject: [PATCH] Replace byte-swapping code with builtins in pack.c

This patch replaces some code for byte-swapping in pack.c with the 
builtin functions allowing the compiler to do its optimization magic
---
  src/mesa/main/pack.c |   22 ++--------------------
  1 file changed, 2 insertions(+), 20 deletions(-)

diff --git a/src/mesa/main/pack.c b/src/mesa/main/pack.c
index 94a6d28..9bfde39 100644
--- a/src/mesa/main/pack.c
+++ b/src/mesa/main/pack.c
@@ -230,26 +230,8 @@ _mesa_pack_bitmap( GLint width, GLint height, const 
GLubyte
  *source,
     }
  }

-
-#define SWAP2BYTE(VALUE)            \
-   {                        \
-      GLubyte *bytes = (GLubyte *) &(VALUE);    \
-      GLubyte tmp = bytes[0];            \
-      bytes[0] = bytes[1];            \
-      bytes[1] = tmp;                \
-   }
-
-#define SWAP4BYTE(VALUE)            \
-   {                        \
-      GLubyte *bytes = (GLubyte *) &(VALUE);    \
-      GLubyte tmp = bytes[0];            \
-      bytes[0] = bytes[3];            \
-      bytes[3] = tmp;                \
-      tmp = bytes[1];                \
-      bytes[1] = bytes[2];            \
-      bytes[2] = tmp;                \
-   }
-
+#define SWAP2BYTE(VALUE) __builtin_bswap16(VALUE)
+#define SWAP4BYTE(VALUE) __builtin_bswap32(VALUE)

  static void
  extract_uint_indexes(GLuint n, GLuint indexes[],
-- 
1.7.9.5

-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Replace-byte-swapping-code-with-builtins-in-pack.c.patch
Type: text/x-patch
Size: 1368 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20171003/e87ed6a7/attachment-0001.bin>