Re: [patch] Accelerate CAIRO_BITSWAP8 on 64 bit machines

Thank Petr.

About SIZEOF(XXX):
We cannot use "#if sizeof(intptr_t)>=8" because GCC refuses to compile that code.
We have to use SIZEOF_VOID_P, but no other choice. There is only SIZEOF_VOID_P in config.h, no SIZEOF_INTPTR_XXX.

About long long:
  On Windows 64bit: [1]
  sizeof(long long) == 8, sizeof(void *) == 8
  On Linux 64bit: [2]
  sizeof(long long) == 8, sizeof(void *) == 8

Reference:
[1] http://msdn.microsoft.com/en-us/library/cc953fe1(v=vs.80).aspx;
(checked by Microsoft Visual C++ Express 2010 on Windows 7 64bit) 
[2] http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html;
(checked by GCC 4.6.3 also)

Hence we use 0x80200802LLU, not 0x80200802LU.

New patch:
Description: 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 on 64 bit machines.
Signed-off-by: Dongsheng Xing <dongsheng.xing at intel.com>
---
 src/cairoint.h |    4 ++++
 1 file changed, 4 insertions(+)

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.
  *
--
1.7.9.5

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