Re: [patch] Accelerate CAIRO_BITSWAP8 on 64 bit machines
"Xing, Dongsheng" <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <720BD6C0640BA94687C456A78160D41D12D503@SHSMSX101.ccr.corp.intel.com> |
> -----Original Message----- > From: Chris Wilson > Sent: Tuesday, May 29, 2012 4:00 PM > To: Xing, Dongsheng; [email protected] > Subject: Re: [cairo] [patch] Accelerate CAIRO_BITSWAP8 on 64 bit machines > > From: Chris Wilson > > Sent: Tuesday, May 29, 2012 3:25 PM > > To: Xing, Dongsheng; [email protected] > > Subject: Re: [cairo] [patch] Accelerate CAIRO_BITSWAP8 on 64 bit > > machines > > > > > On Tue, 29 May 2012 02:03:58 +0000, "Xing, Dongsheng" wrote: > > > > 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 on 64 bit machines. > > > > > > This doesn't apply to master. Care to resend? > > It justs means that the parent of this patch is not known upstream and by my repository so git can not reconstruct the right patch for me. > > > A more appropriate test here would be that "SIZEOF_LONG_LONG >= 8" as that is the condition used in the macro. > > > I think SIZEOF_LONG >= 8 is better. Because sizeof(long long)==8 on a 32 bit machine. And SIZEOF_LONG is the length of a native processor word. > Ok, if we can use SIZEOF_LONG here, wouuld 0x80200802LU suffice? > -Chris Yes, 0x80200802LU is suffice. The patch has been modified accordingly. The patch is now known upstream. Best regards, Dongsheng From 3ed3ecbc03435f79369e1d840b488d5a8add1983 Mon Sep 17 00:00:00 2001 From: Dongsheng Xing <[email protected]> Date: Tue, 29 May 2012 16:14:19 +0800 Subject: [PATCH] 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. --- src/cairoint.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/cairoint.h b/src/cairoint.h index 2c9f2dd..96e2c1f 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_LONG >= 8) +#define CAIRO_BITSWAP8(c) ((((c) * 0x80200802LU & 0x884422110LU) * 0x101010101LU) >> 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 -- cairo mailing list [email protected] http://lists.cairographics.org/mailman/listinfo/cairo