sse implementation of imdct.

patch mostly by Zuxy Meng (zuxy dot meng at gmail dot com)

Originally committed as revision 6311 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dsputil.h

@@ -667,6 +667,8 @@ void ff_imdct_calc(MDCTContext *s, FFTSample *output,
                 const FFTSample *input, FFTSample *tmp);
 void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
                         const FFTSample *input, FFTSample *tmp);
+void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
+                       const FFTSample *input, FFTSample *tmp);
 void ff_mdct_calc(MDCTContext *s, FFTSample *out,
                const FFTSample *input, FFTSample *tmp);
 void ff_mdct_end(MDCTContext *s);

libavcodec/fft.c

@@ -65,17 +65,18 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
 
         if (has_vectors) {
 #if defined(HAVE_MMX)
-            if (has_vectors & MM_3DNOWEXT)
+            if (has_vectors & MM_3DNOWEXT) {
-                s->imdct_calc = ff_imdct_calc_3dn2;
-            if (has_vectors & MM_3DNOWEXT)
                 /* 3DNowEx for K7/K8 */
+                s->imdct_calc = ff_imdct_calc_3dn2;
                 s->fft_calc = ff_fft_calc_3dn2;
-            else if (has_vectors & MM_3DNOW)
+            } else if (has_vectors & MM_3DNOW) {
                 /* 3DNow! for K6-2/3 */
                 s->fft_calc = ff_fft_calc_3dn;
-            else if (has_vectors & MM_SSE)
+            } else if (has_vectors & MM_SSE) {
                 /* SSE for P3/P4 */
+                s->imdct_calc = ff_imdct_calc_sse;
                 s->fft_calc = ff_fft_calc_sse;
+            }
 #else /* HAVE_MMX */
             if (has_vectors & MM_ALTIVEC)
                 s->fft_calc = ff_fft_calc_altivec;

libavcodec/i386/fft_sse.c

@@ -27,6 +27,12 @@ static const int p1p1m1p1[4] __attribute__((aligned(16))) =
 static const int p1p1m1m1[4] __attribute__((aligned(16))) =
     { 0, 0, 1 << 31, 1 << 31 };
 
+static const int p1m1p1m1[4] __attribute__((aligned(16))) =
+    { 0, 1 << 31, 0, 1 << 31 };
+
+static const int m1m1m1m1[4] __attribute__((aligned(16))) =
+    { 1 << 31, 1 << 31, 1 << 31, 1 << 31 };
+
 #if 0
 static void print_v4sf(const char *str, __m128 a)
 {
@@ -118,3 +124,122 @@ void ff_fft_calc_sse(FFTContext *s, FFTComplex *z)
     } while (nblocks != 0);
 }
 
+void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
+                       const FFTSample *input, FFTSample *tmp)
+{
+    long k, n8, n4, n2, n;
+    const uint16_t *revtab = s->fft.revtab;
+    const FFTSample *tcos = s->tcos;
+    const FFTSample *tsin = s->tsin;
+    const FFTSample *in1, *in2;
+    FFTComplex *z = (FFTComplex *)tmp;
+
+    n = 1 << s->nbits;
+    n2 = n >> 1;
+    n4 = n >> 2;
+    n8 = n >> 3;
+
+    asm volatile ("movaps %0, %%xmm7\n\t"::"m"(*p1m1p1m1));
+
+    /* pre rotation */
+    in1 = input;
+    in2 = input + n2 - 4;
+
+    /* Complex multiplication
+       Two complex products per iteration, we could have 4 with 8 xmm
+       registers, 8 with 16 xmm registers.
+       Maybe we should unroll more.
+    */
+    for (k = 0; k < n4; k += 2) {
+        asm volatile (
+            "movaps          %0, %%xmm0 \n\t"   // xmm0 = r0 X  r1 X : in2
+            "movaps          %1, %%xmm3 \n\t"   // xmm3 = X  i1 X  i0: in1
+            "movlps          %2, %%xmm1 \n\t"   // xmm1 = X  X  R1 R0: tcos
+            "movlps          %3, %%xmm2 \n\t"   // xmm2 = X  X  I1 I0: tsin
+            "shufps $95, %%xmm0, %%xmm0 \n\t"   // xmm0 = r1 r1 r0 r0
+            "shufps $160,%%xmm3, %%xmm3 \n\t"   // xmm3 = i1 i1 i0 i0
+            "unpcklps    %%xmm2, %%xmm1 \n\t"   // xmm1 = I1 R1 I0 R0
+            "movaps      %%xmm1, %%xmm2 \n\t"   // xmm2 = I1 R1 I0 R0
+            "xorps       %%xmm7, %%xmm2 \n\t"   // xmm2 = -I1 R1 -I0 R0
+            "mulps       %%xmm1, %%xmm0 \n\t"   // xmm0 = rI rR rI rR
+            "shufps $177,%%xmm2, %%xmm2 \n\t"   // xmm2 = R1 -I1 R0 -I0
+            "mulps       %%xmm2, %%xmm3 \n\t"   // xmm3 = Ri -Ii Ri -Ii
+            "addps       %%xmm3, %%xmm0 \n\t"   // xmm0 = result
+            ::"m"(in2[-2*k]), "m"(in1[2*k]),
+              "m"(tcos[k]), "m"(tsin[k])
+        );
+        /* Should be in the same block, hack for gcc2.95 & gcc3 */
+        asm (
+            "movlps      %%xmm0, %0     \n\t"
+            "movhps      %%xmm0, %1     \n\t"
+            :"=m"(z[revtab[k]]), "=m"(z[revtab[k + 1]])
+        );
+    }
+
+    ff_fft_calc_sse(&s->fft, z);
+
+    /* Not currently needed, added for safety */
+    asm volatile ("movaps %0, %%xmm7\n\t"::"m"(*p1m1p1m1));
+
+    /* post rotation + reordering */
+    for (k = 0; k < n4; k += 2) {
+        asm (
+            "movaps          %0, %%xmm0 \n\t"   // xmm0 = i1 r1 i0 r0: z
+            "movlps          %1, %%xmm1 \n\t"   // xmm1 = X  X  R1 R0: tcos
+            "movaps      %%xmm0, %%xmm3 \n\t"   // xmm3 = i1 r1 i0 r0
+            "movlps          %2, %%xmm2 \n\t"   // xmm2 = X  X  I1 I0: tsin
+            "shufps $160,%%xmm0, %%xmm0 \n\t"   // xmm0 = r1 r1 r0 r0
+            "shufps $245,%%xmm3, %%xmm3 \n\t"   // xmm3 = i1 i1 i0 i0
+            "unpcklps    %%xmm2, %%xmm1 \n\t"   // xmm1 = I1 R1 I0 R0
+            "movaps      %%xmm1, %%xmm2 \n\t"   // xmm2 = I1 R1 I0 R0
+            "xorps       %%xmm7, %%xmm2 \n\t"   // xmm2 = -I1 R1 -I0 R0
+            "mulps       %%xmm1, %%xmm0 \n\t"   // xmm0 = rI rR rI rR
+            "shufps $177,%%xmm2, %%xmm2 \n\t"   // xmm2 = R1 -I1 R0 -I0
+            "mulps       %%xmm2, %%xmm3 \n\t"   // xmm3 = Ri -Ii Ri -Ii
+            "addps       %%xmm3, %%xmm0 \n\t"   // xmm0 = result
+            "movaps      %%xmm0, %0     \n\t"
+            :"+m"(z[k])
+            :"m"(tcos[k]), "m"(tsin[k])
+        );
+    }
+
+    /*
+       Mnemonics:
+       0 = z[k].re
+       1 = z[k].im
+       2 = z[k + 1].re
+       3 = z[k + 1].im
+       4 = z[-k - 2].re
+       5 = z[-k - 2].im
+       6 = z[-k - 1].re
+       7 = z[-k - 1].im
+    */
+    k = 16-n;
+    asm volatile("movaps %0, %%xmm7 \n\t"::"m"(*m1m1m1m1));
+    asm volatile(
+        "1: \n\t"
+        "movaps  -16(%4,%0), %%xmm1 \n\t"   // xmm1 = 4 5 6 7 = z[-2-k]
+        "neg %0 \n\t"
+        "movaps     (%4,%0), %%xmm0 \n\t"   // xmm0 = 0 1 2 3 = z[k]
+        "xorps       %%xmm7, %%xmm0 \n\t"   // xmm0 = -0 -1 -2 -3
+        "movaps      %%xmm0, %%xmm2 \n\t"   // xmm2 = -0 -1 -2 -3
+        "shufps $141,%%xmm1, %%xmm0 \n\t"   // xmm0 = -1 -3 4 6
+        "shufps $216,%%xmm1, %%xmm2 \n\t"   // xmm2 = -0 -2 5 7
+        "shufps $156,%%xmm0, %%xmm0 \n\t"   // xmm0 = -1 6 -3 4 !
+        "shufps $156,%%xmm2, %%xmm2 \n\t"   // xmm2 = -0 7 -2 5 !
+        "movaps      %%xmm0, (%1,%0) \n\t"  // output[2*k]
+        "movaps      %%xmm2, (%2,%0) \n\t"  // output[n2+2*k]
+        "neg %0 \n\t"
+        "shufps $27, %%xmm0, %%xmm0 \n\t"   // xmm0 = 4 -3 6 -1
+        "xorps       %%xmm7, %%xmm0 \n\t"   // xmm0 = -4 3 -6 1 !
+        "shufps $27, %%xmm2, %%xmm2 \n\t"   // xmm2 = 5 -2 7 -0 !
+        "movaps      %%xmm0, -16(%2,%0) \n\t" // output[n2-4-2*k]
+        "movaps      %%xmm2, -16(%3,%0) \n\t" // output[n-4-2*k]
+        "add $16, %0 \n\t"
+        "jle 1b \n\t"
+        :"+r"(k)
+        :"r"(output), "r"(output+n2), "r"(output+n), "r"(z+n8)
+        :"memory"
+    );
+}
+