Re: [Mjpeg-developer] [PATCH] sync bsumsq_sub22_mmx() with C-reference code

[Gert V. <ger...@hc...>]

Stephen Beahm wrote:

>Hello,
>
>Both the C-reference and altivec versions of bsumsq_sub22_mmx() implement the 
>following:
>	v = ((p1f[i]+p1b[i]+1)>>1) - p2[i];
>
>The mmx version does not add the one (+1).
>
>I am rather new to the mmx instruction set, so maybe someone else can clean 
>this patch up? Thanks.
>
>
>Index: utils/mmxsse/mblock_sumsq_mmx.c
>===================================================================
>RCS file: /cvsroot/mjpeg/mjpeg_play/utils/mmxsse/mblock_sumsq_mmx.c,v
>retrieving revision 1.1
>diff -u -r1.1 mblock_sumsq_mmx.c
>--- utils/mmxsse/mblock_sumsq_mmx.c	26 Dec 2004 05:29:39 -0000	1.1
>+++ utils/mmxsse/mblock_sumsq_mmx.c	17 Mar 2005 04:54:32 -0000
>@@ -409,6 +409,14 @@
> {
> 	int sum,sum1,sum2;
> 
>+	/* Load 1 into one_q */
>+	int one = 1;
>+	uint64_t one_q;
>+	movd_g2r(one, mm7);
>+	punpcklwd_r2r(mm7, mm7);
>+	punpckldq_r2r(mm7, mm7);
>+	movq_r2m(mm7, one_q);
>+
> 	pxor_r2r(mm5, mm5);
> 	
>
This could be replaced with a constant containing 4 words with the value 1.
See patch below.

   Gert

diff -u -r1.1 mblock_sumsq_mmx.c
--- mblock_sumsq_mmx.c  26 Dec 2004 05:29:39 -0000      1.1
+++ mblock_sumsq_mmx.c  29 Mar 2005 17:02:14 -0000
@@ -407,6 +407,7 @@

 int bsumsq_sub22_mmx(uint8_t *blk1f, uint8_t *blk1b, uint8_t *blk2, int 
lx, int h)
 {
+       static const uint16_t ones[4]={1,1,1,1};
        int sum,sum1,sum2;

        pxor_r2r(mm5, mm5);
@@ -431,10 +432,12 @@
                        punpckhbw_r2r(mm7, mm3);

                                paddw_r2r(mm4, mm0);
+                               paddw_m2r(*ones, mm0);
                                psrlw_i2r(1, mm0);
                        psubw_r2r(mm2, mm0);
                        pmaddwd_r2r(mm0, mm0);
                                paddw_r2r(mm6, mm1);
+                               paddw_m2r(*ones, mm1);
                                psrlw_i2r(1, mm1);
                        psubw_r2r(mm3, mm1);
                        pmaddwd_r2r(mm1, mm1);