]> git.sesse.net Git - qscale/blobdiff - qscale.c
Fix behavior for input images not aligned on a DCT block.
[qscale] / qscale.c
index 8fecd666a972b1fad7a35b302dc5f8445677aca0..8ceb53eb0ea8565d31cf72df64c8814154c9b991 100644 (file)
--- a/qscale.c
+++ b/qscale.c
@@ -1,18 +1,25 @@
 #include <stdio.h>
+#include <malloc.h>
 #include <math.h>
 #include <string.h>
 #include <stdlib.h>
 #include "jpeglib.h"
 
-#define CACHE_LINE_FACTOR 8
+#define CACHE_LINE_FACTOR 16
 
 double sinc(double x)
 {
-       // This is bad for very small x, should use power series instead.
-       if (x == 0.0)
-               return 1.0;
-       else
+       static const double cutoff = 1.220703668e-4;  // sqrt(sqrt(eps))
+
+       if (abs(x) < cutoff) {
+               // For small |x|, use Taylor series instead
+               const double x2 = x * x;
+               const double x4 = x2 * x2;
+
+               return 1.0 - x2 / 6.0 + x4 / 120.0;
+       } else {
                return sin(x) / x;
+       }
 }
 
 double lanczos_tap(double x)
@@ -31,13 +38,13 @@ struct pix_desc {
        unsigned startcoeff;
 };
 
-void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned dstride)
+void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned sstride, unsigned dstride)
 {
        struct pix_desc *pd = (struct pix_desc *)malloc(nw * sizeof(struct pix_desc));
        int size_coeffs = 8;
        float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
        int num_coeffs = 0;
-       int x, y, sx;
+       int x, y;
        double sf = (double)w / (double)nw;
        double support = (w > nw) ? (3.0 * sf) : (3.0 / sf);
 
@@ -45,6 +52,7 @@ void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw
        for (x = 0; x < nw; ++x) {
                int start = ceil(x * sf - support);
                int end = floor(x * sf + support);
+               int sx;
                double sum = 0.0;
 
                if (start < 0) {
@@ -54,6 +62,19 @@ void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw
                        end = w - 1;
                }
 
+               // round up so we get a multiple of four for the SSE code
+               int num = (end - start + 1);
+               if (num % 4 != 0) {
+                       // prefer aligning it if possible
+                       if (start % 4 != 0 && start % 4 <= num % 4) {
+                               num += start % 4;
+                               start -= start % 4;
+                       }
+                       if (num % 4 != 0) {
+                               end += 4 - (num % 4);
+                       }
+               }
+
                pd[x].start = start;
                pd[x].end = end;
                pd[x].startcoeff = num_coeffs;
@@ -76,18 +97,37 @@ void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw
        }
        
        for (y = 0; y < h; ++y) {
-               float *sptr = pix + y*w;
+               float *sptr = pix + y*sstride;
                unsigned char *dptr = npix + y*dstride;
-               unsigned char ch = 0;
+               unsigned char ch;
                for (x = 0; x < nw; ++x) {
-                       float acc = 0.0;
-                       float *cf = &coeffs[pd[x].startcoeff];
-                       unsigned sx;
-                       
-                       for (sx = pd[x].start; sx <= pd[x].end; ++sx) {
-                               acc += sptr[sx] * *cf++;
-                       }
-
+                       float acc;
+                       static const float low = 0.0, high = 255.0;
+                       asm (
+                               "pxor %0, %0               \n"
+                               "xor %%eax, %%eax          \n"
+                               ".lbl2:                    \n"
+                               "movups (%2,%%eax),%%xmm1  \n"
+                               "movups (%1,%%eax),%%xmm2  \n"
+                               "mulps %%xmm2,%%xmm1       \n"
+                               "addps %%xmm1,%0           \n"
+                               "addl $16,%%eax            \n"
+                               "dec %3                    \n"
+                               "jnz .lbl2                 \n"
+                               "haddps %0,%0              \n"
+                               "haddps %0,%0              \n"
+                               "maxss %4,%0               \n"
+                               "minss %5,%0               \n"
+                               : "=x" (acc)
+                               : "r" (&coeffs[pd[x].startcoeff]),
+                                 "r" (&sptr[pd[x].start]),
+                                 "r" ((pd[x].end - pd[x].start + 1)/4),
+                                 "m" (low),
+                                 "m" (high)
+                               : "eax", "xmm1", "xmm2"
+                       );
+
+#if 0
                        if (acc < 0.0)
                                ch = 0;
                        else if (acc > 255.0)
@@ -95,7 +135,10 @@ void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw
                        else
                                ch = (unsigned char)acc;
                        *dptr++ = ch;
+#endif
+                       *dptr++ = (unsigned char)acc;
                }
+               ch = dptr[-1];
                for ( ; x < dstride; ++x) {
                        *dptr++ = ch;
                }
@@ -147,19 +190,19 @@ void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh
        }
 
 #if CACHE_LINE_FACTOR > 1
-       for (x = 0; x < w; x += CACHE_LINE_FACTOR) {
+       for (x = 0; x < (w/CACHE_LINE_FACTOR) * CACHE_LINE_FACTOR; x += CACHE_LINE_FACTOR) {
                unsigned char *sptr = pix + x;
                float *dptr = npix + x;
                for (y = 0; y < nh; ++y) {
+#if 0
                        int i;
                        float acc[CACHE_LINE_FACTOR];
                        for (i = 0; i < CACHE_LINE_FACTOR; ++i)
                                acc[i] = 0.0;
                        float *cf = &coeffs[pd[y].startcoeff];
                        unsigned sy;
-                       
+               
                        for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
-                               //asm volatile ("prefetcht0 %0" :: "m" (sptr[(sy+1) * w]));
                                for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
                                        acc[i] += sptr[sy * w + i] * *cf;
                                }
@@ -169,6 +212,95 @@ void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh
                        for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
                                dptr[i] = acc[i];
                        }
+#else
+                       /*
+                        * xmm0 - xmm3: acc[0..15]
+                        * xmm4: current filter coefficient
+                        * xmm5, xmm6, xmm7: scratchpad
+                        */
+                       asm (
+                               /* clear */
+                               "pxor %%xmm0, %%xmm0    \n"
+                               "pxor %%xmm1, %%xmm1    \n"
+                               "pxor %%xmm2, %%xmm2    \n"
+                               "pxor %%xmm3, %%xmm3    \n"
+
+                               /* main loop */
+                               ".lbl:                   \n"
+                               
+                               /* a zero is useful during unpacking */
+                               "pxor %%xmm4, %%xmm4     \n"
+                               
+                               /* fetch all 16 source bytes */
+                               "movups (%0), %%xmm5     \n"
+                               "prefetcht0 (%0,%3,4)    \n"
+
+                               /* unpack into words (xmm5, xmm7) */
+                               "movaps %%xmm5, %%xmm7    \n"
+                               "punpcklbw %%xmm4, %%xmm5 \n"
+                               "punpckhbw %%xmm4, %%xmm7 \n"
+
+                               /* unpack xmm5 into dwords (xmm5, xmm6) */
+                               "movaps %%xmm5, %%xmm6    \n"
+                               "punpcklwd %%xmm4, %%xmm5 \n"
+                               "punpckhwd %%xmm4, %%xmm6 \n"
+
+                               /* convert xmm5, xmm6 to floats */
+                               "cvtdq2ps %%xmm5, %%xmm5 \n"
+                               "cvtdq2ps %%xmm6, %%xmm6 \n"
+
+                               /* fetch the coefficient */
+                               "movss (%2), %%xmm4      \n"
+                               "shufps $0x0, %%xmm4, %%xmm4 \n"
+
+                               /* do the muls for xmm5 and xmm6 */
+                               "mulps %%xmm4, %%xmm5    \n"
+                               "mulps %%xmm4, %%xmm6    \n"
+                               "addps %%xmm5, %%xmm0    \n"
+                               "addps %%xmm6, %%xmm1    \n"
+
+                               /* get the zero back again */
+                               "pxor %%xmm4, %%xmm4     \n"
+
+                               /* unpack xmm7 into dwords (xmm7, xmm6) */
+                               "movaps %%xmm7, %%xmm6    \n"
+                               "punpcklwd %%xmm4, %%xmm7 \n"
+                               "punpckhwd %%xmm4, %%xmm6 \n"
+
+                               /* convert xmm7, xmm6 to floats */
+                               "cvtdq2ps %%xmm7, %%xmm7 \n"
+                               "cvtdq2ps %%xmm6, %%xmm6 \n"
+
+                               /* fetch the coefficient */
+                               "movss (%2), %%xmm4      \n"
+                               "shufps $0x0, %%xmm4, %%xmm4 \n"
+
+                               /* do the second set of muls */
+                               "mulps %%xmm4, %%xmm7    \n"
+                               "mulps %%xmm4, %%xmm6    \n"
+                               "addps %%xmm7, %%xmm2    \n"
+                               "addps %%xmm6, %%xmm3    \n"
+
+                               /* move along, and loop */
+                               "add $4, %2              \n"
+                               "add %3, %0              \n"
+                               "dec %1                  \n"
+                               "jnz .lbl                \n"
+
+                               /* store the values */
+                               "movaps %%xmm0, (%4)     \n"
+                               "movaps %%xmm1, 16(%4)   \n"
+                               "movaps %%xmm2, 32(%4)   \n"
+                               "movaps %%xmm3, 48(%4)   \n"
+                               : :
+                               "r" (&sptr[pd[y].start * w]),        /* 0: srcptr base */
+                               "r" (pd[y].end - pd[y].start + 1),   /* 1: filter len */
+                               "r" (&coeffs[pd[y].startcoeff]),     /* 2: coeffs base */
+                               "r" (w),                             /* 3: stride */
+                               "r" (dptr)                           /* 4: dstptr base */
+                               : "memory", "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7"
+                       );
+#endif
                        dptr += dstride;
                }
        }
@@ -220,14 +352,18 @@ int main(int argc, char **argv)
        dinfo.raw_data_out = TRUE;
        jpeg_start_decompress(&dinfo);
 
+       unsigned w0 = dinfo.image_width * samp_h0 / max_samp_h, h0 = dinfo.image_height * samp_v0 / max_samp_v;
+       unsigned w1 = dinfo.image_width * samp_h1 / max_samp_h, h1 = dinfo.image_height * samp_v1 / max_samp_v;
+       unsigned w2 = dinfo.image_width * samp_h2 / max_samp_h, h2 = dinfo.image_height * samp_v2 / max_samp_v;
+
        fprintf(stderr, "Scaling using Lanczos filter:\n");
        fprintf(stderr, "  Y component: %ux%u -> %ux%u\n", dinfo.comp_info[0].width_in_blocks * DCTSIZE, dinfo.comp_info[0].height_in_blocks * DCTSIZE, nw0, nh0);
        fprintf(stderr, "  Cb component: %ux%u -> %ux%u\n", dinfo.comp_info[1].width_in_blocks * DCTSIZE, dinfo.comp_info[1].height_in_blocks * DCTSIZE, nw1, nh1);
        fprintf(stderr, "  Cr component: %ux%u -> %ux%u\n", dinfo.comp_info[2].width_in_blocks * DCTSIZE, dinfo.comp_info[2].height_in_blocks * DCTSIZE, nw2, nh2);
 
-       JSAMPLE *data_y  = (JSAMPLE*)malloc(dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
-       JSAMPLE *data_cb = (JSAMPLE*)malloc(dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
-       JSAMPLE *data_cr = (JSAMPLE*)malloc(dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
+       JSAMPLE *data_y  = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
+       JSAMPLE *data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
+       JSAMPLE *data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
        JSAMPLE *data_ny, *data_ncb, *data_ncr;
 
        int total_lines = 0, blocks = 0;
@@ -254,24 +390,24 @@ int main(int argc, char **argv)
        }
 
        {
-               float *npix = (float*)malloc(dinfo.comp_info[0].width_in_blocks * DCTSIZE * nh0 * sizeof(float));       
-               vscale(data_y, npix, dinfo.comp_info[0].width_in_blocks * DCTSIZE, dinfo.comp_info[0].height_in_blocks * DCTSIZE, nh0, dinfo.comp_info[0].width_in_blocks * DCTSIZE);
+               float *npix = (float*)memalign(16, dinfo.comp_info[0].width_in_blocks * DCTSIZE * nh0 * sizeof(float)); 
+               vscale(data_y, npix, dinfo.comp_info[0].width_in_blocks * DCTSIZE, h0, nh0, dinfo.comp_info[0].width_in_blocks * DCTSIZE);
                data_ny = (unsigned char *)malloc(nw0 * stride0);
-               hscale(npix, data_ny, dinfo.comp_info[0].width_in_blocks * DCTSIZE, nh0, nw0, stride0);
+               hscale(npix, data_ny, w0, nh0, nw0, dinfo.comp_info[0].width_in_blocks * DCTSIZE, stride0);
                free(npix);
        }
        {
-               float *npix = (float*)malloc(dinfo.comp_info[1].width_in_blocks * DCTSIZE * nh1 * sizeof(float));       
-               vscale(data_cr, npix, dinfo.comp_info[1].width_in_blocks * DCTSIZE, dinfo.comp_info[1].height_in_blocks * DCTSIZE, nh1, dinfo.comp_info[1].width_in_blocks * DCTSIZE);
+               float *npix = (float*)memalign(16, dinfo.comp_info[1].width_in_blocks * DCTSIZE * nh1 * sizeof(float)); 
+               vscale(data_cr, npix, dinfo.comp_info[1].width_in_blocks * DCTSIZE, h1, nh1, dinfo.comp_info[1].width_in_blocks * DCTSIZE);
                data_ncr = (unsigned char *)malloc(nw1 * stride1);
-               hscale(npix, data_ncr, dinfo.comp_info[1].width_in_blocks * DCTSIZE, nh1, nw1, stride1);
+               hscale(npix, data_ncr, w1, nh1, nw1, dinfo.comp_info[1].width_in_blocks * DCTSIZE, stride1);
                free(npix);
        }
        {
-               float *npix = (float*)malloc(dinfo.comp_info[2].width_in_blocks * DCTSIZE * nh2 * sizeof(float));       
-               vscale(data_cb, npix, dinfo.comp_info[2].width_in_blocks * DCTSIZE, dinfo.comp_info[2].height_in_blocks * DCTSIZE, nh2, dinfo.comp_info[2].width_in_blocks * DCTSIZE);
+               float *npix = (float*)memalign(16, dinfo.comp_info[2].width_in_blocks * DCTSIZE * nh2 * sizeof(float)); 
+               vscale(data_cb, npix, dinfo.comp_info[2].width_in_blocks * DCTSIZE, h2, nh2, dinfo.comp_info[2].width_in_blocks * DCTSIZE);
                data_ncb = (unsigned char *)malloc(nw2 * stride2);
-               hscale(npix, data_ncb, dinfo.comp_info[2].width_in_blocks * DCTSIZE, nh2, nw2, stride2);
+               hscale(npix, data_ncb, w2, nh2, nw2, dinfo.comp_info[2].width_in_blocks * DCTSIZE, stride2);
                free(npix);
        }
        jpeg_destroy_decompress(&dinfo);