[SCM] libav/experimental: altivec accelerated v-resample patch by (Brian Foley <bfoley at compsoc dot nuigalway dot ie>)
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 15:34:25 UTC 2013
The following commit has been merged in the experimental branch:
commit 404d2241ec55bc6048eeb7c09bc7cdb248ecf632
Author: Brian Foley <bfoley at compsoc.nuigalway.ie>
Date: Tue Nov 26 09:21:01 2002 +0000
altivec accelerated v-resample patch by (Brian Foley <bfoley at compsoc dot nuigalway dot ie>)
Originally committed as revision 1283 to svn://svn.ffmpeg.org/ffmpeg/trunk
diff --git a/libavcodec/dsputil.h b/libavcodec/dsputil.h
index 0b1d34f..29aca1a 100644
--- a/libavcodec/dsputil.h
+++ b/libavcodec/dsputil.h
@@ -190,6 +190,10 @@ void dsputil_init_alpha(DSPContext* c, unsigned mask);
#elif defined(ARCH_POWERPC)
+#define MM_ALTIVEC 0x0001 /* standard AltiVec */
+
+extern int mm_flags;
+
#define __align8 __attribute__ ((aligned (16)))
void dsputil_init_ppc(DSPContext* c, unsigned mask);
diff --git a/libavcodec/imgresample.c b/libavcodec/imgresample.c
index 1197f85..630f2eb 100644
--- a/libavcodec/imgresample.c
+++ b/libavcodec/imgresample.c
@@ -22,7 +22,7 @@
#ifdef USE_FASTMEMCPY
#include "fastmemcpy.h"
#endif
-
+extern int mm_flags;
#define NB_COMPONENTS 3
@@ -264,6 +264,133 @@ static void v_resample4_mmx(UINT8 *dst, int dst_width, UINT8 *src, int wrap,
}
#endif
+#ifdef HAVE_ALTIVEC
+typedef union {
+ vector unsigned char v;
+ unsigned char c[16];
+} vec_uc_t;
+
+typedef union {
+ vector signed short v;
+ signed short s[8];
+} vec_ss_t;
+
+void v_resample16_altivec(UINT8 *dst, int dst_width, UINT8 *src, int wrap,
+ INT16 *filter)
+{
+ int sum, i;
+ uint8_t *s;
+ vector unsigned char *tv, tmp, dstv, zero;
+ vec_ss_t srchv[4], srclv[4], fv[4];
+ vector signed short zeros, sumhv, sumlv;
+ s = src;
+
+ for(i=0;i<4;i++)
+ {
+ /*
+ The vec_madds later on does an implicit >>15 on the result.
+ Since FILTER_BITS is 8, and we have 15 bits of magnitude in
+ a signed short, we have just enough bits to pre-shift our
+ filter constants <<7 to compensate for vec_madds.
+ */
+ fv[i].s[0] = filter[i] << (15-FILTER_BITS);
+ fv[i].v = vec_splat(fv[i].v, 0);
+ }
+
+ zero = vec_splat_u8(0);
+ zeros = vec_splat_s16(0);
+
+
+ /*
+ When we're resampling, we'd ideally like both our input buffers,
+ and output buffers to be 16-byte aligned, so we can do both aligned
+ reads and writes. Sadly we can't always have this at the moment, so
+ we opt for aligned writes, as unaligned writes have a huge overhead.
+ To do this, do enough scalar resamples to get dst 16-byte aligned.
+ */
+ i = (16-((int)dst) & 0xf) & 0xf;
+ while(i>0) {
+ sum = s[0 * wrap] * filter[0] +
+ s[1 * wrap] * filter[1] +
+ s[2 * wrap] * filter[2] +
+ s[3 * wrap] * filter[3];
+ sum = sum >> FILTER_BITS;
+ if (sum<0) sum = 0; else if (sum>255) sum=255;
+ dst[0] = sum;
+ dst++;
+ s++;
+ dst_width--;
+ i--;
+ }
+
+ /* Do our altivec resampling on 16 pixels at once. */
+ while(dst_width>=16) {
+ /*
+ Read 16 (potentially unaligned) bytes from each of
+ 4 lines into 4 vectors, and split them into shorts.
+ Interleave the multipy/accumulate for the resample
+ filter with the loads to hide the 3 cycle latency
+ the vec_madds have.
+ */
+ tv = (vector unsigned char *) &s[0 * wrap];
+ tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[i * wrap]));
+ srchv[0].v = (vector signed short) vec_mergeh(zero, tmp);
+ srclv[0].v = (vector signed short) vec_mergel(zero, tmp);
+ sumhv = vec_madds(srchv[0].v, fv[0].v, zeros);
+ sumlv = vec_madds(srclv[0].v, fv[0].v, zeros);
+
+ tv = (vector unsigned char *) &s[1 * wrap];
+ tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[1 * wrap]));
+ srchv[1].v = (vector signed short) vec_mergeh(zero, tmp);
+ srclv[1].v = (vector signed short) vec_mergel(zero, tmp);
+ sumhv = vec_madds(srchv[1].v, fv[1].v, sumhv);
+ sumlv = vec_madds(srclv[1].v, fv[1].v, sumlv);
+
+ tv = (vector unsigned char *) &s[2 * wrap];
+ tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[2 * wrap]));
+ srchv[2].v = (vector signed short) vec_mergeh(zero, tmp);
+ srclv[2].v = (vector signed short) vec_mergel(zero, tmp);
+ sumhv = vec_madds(srchv[2].v, fv[2].v, sumhv);
+ sumlv = vec_madds(srclv[2].v, fv[2].v, sumlv);
+
+ tv = (vector unsigned char *) &s[3 * wrap];
+ tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[3 * wrap]));
+ srchv[3].v = (vector signed short) vec_mergeh(zero, tmp);
+ srclv[3].v = (vector signed short) vec_mergel(zero, tmp);
+ sumhv = vec_madds(srchv[3].v, fv[3].v, sumhv);
+ sumlv = vec_madds(srclv[3].v, fv[3].v, sumlv);
+
+ /*
+ Pack the results into our destination vector,
+ and do an aligned write of that back to memory.
+ */
+ dstv = vec_packsu(sumhv, sumlv) ;
+ vec_st(dstv, 0, (vector unsigned char *) dst);
+
+ dst+=16;
+ s+=16;
+ dst_width-=16;
+ }
+
+ /*
+ If there are any leftover pixels, resample them
+ with the slow scalar method.
+ */
+ while(dst_width>0) {
+ sum = s[0 * wrap] * filter[0] +
+ s[1 * wrap] * filter[1] +
+ s[2 * wrap] * filter[2] +
+ s[3 * wrap] * filter[3];
+ sum = sum >> FILTER_BITS;
+ if (sum<0) sum = 0; else if (sum>255) sum=255;
+ dst[0] = sum;
+ dst++;
+ s++;
+ dst_width--;
+ }
+}
+#endif
+
/* slow version to handle limit cases. Does not need optimisation */
static void h_resample_slow(UINT8 *dst, int dst_width, UINT8 *src, int src_width,
int src_start, int src_incr, INT16 *filters)
@@ -384,6 +511,13 @@ static void component_resample(ImgReSampleContext *s,
&s->v_filters[phase_y][0]);
else
#endif
+#ifdef HAVE_ALTIVEC
+ if ((mm_flags & MM_ALTIVEC) && NB_TAPS == 4 && FILTER_BITS == 8)
+ v_resample16_altivec(output, owidth,
+ s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth,
+ &s->v_filters[phase_y][0]);
+ else
+#endif
v_resample(output, owidth,
s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth,
&s->v_filters[phase_y][0]);
diff --git a/libavcodec/ppc/dsputil_ppc.c b/libavcodec/ppc/dsputil_ppc.c
index c4dae6c..ffe3ce0 100644
--- a/libavcodec/ppc/dsputil_ppc.c
+++ b/libavcodec/ppc/dsputil_ppc.c
@@ -23,6 +23,8 @@
#include "dsputil_altivec.h"
#endif
+int mm_flags = 0;
+
void dsputil_init_ppc(DSPContext* c, unsigned mask)
{
// Common optimisations whether Altivec or not
@@ -31,6 +33,8 @@ void dsputil_init_ppc(DSPContext* c, unsigned mask)
#if HAVE_ALTIVEC
if (has_altivec()) {
+ mm_flags |= MM_ALTIVEC;
+
// Altivec specific optimisations
c->pix_abs16x16_x2 = pix_abs16x16_x2_altivec;
c->pix_abs16x16_y2 = pix_abs16x16_y2_altivec;
--
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