Add SSE the other way as well, requiring SSE3.

diff --git a/qscale.c b/qscale.c
index d5536bc36a359aff34690a0e67485c15561af83c..6d529bcb4d1d73c49b314eb036b54915fc7dd258 100644 (file)
--- a/qscale.c
+++ b/qscale.c
@@ -38,7 +38,7 @@ void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw
        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);
 
@@ -46,6 +46,7 @@ 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) {
@@ -55,6 +56,19 @@ 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;
@@ -79,16 +93,35 @@ void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw
        for (y = 0; y < h; ++y) {
                float *sptr = pix + y*w;
                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)
@@ -96,7 +129,10 @@ 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;
                }
@@ -240,9 +276,9 @@ void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh
                                "addps %%xmm6, %%xmm3    \n"
 
                                /* move along, and loop */
-                               "addl $4, %2             \n"
-                               "addl %3, %0             \n"
-                               "decl %1                 \n"
+                               "add $4, %2              \n"
+                               "add %3, %0              \n"
+                               "dec %1                  \n"
                                "jnz .lbl                \n"
 
                                /* store the values */