1 files changed, 168 insertions, 0 deletions
diff --git a/mpg123_artsplugin/mpg123/dct64.c b/mpg123_artsplugin/mpg123/dct64.c
new file mode 100644
index 00000000..59c19676
--- /dev/null
+++ b/mpg123_artsplugin/mpg123/dct64.c
@@ -0,0 +1,168 @@
+
+/*
+ * Discrete Cosine Tansform (DCT) for subband synthesis
+ *
+ * -funroll-loops (for gcc) will remove the loops for better performance
+ * using loops in the source-code enhances readabillity
+ */
+
+/*
+ * TODO: write an optimized version for the down-sampling modes
+ *       (in these modes the bands 16-31 (2:1) or 8-31 (4:1) are zero 
+ */
+
+#include "mpg123.h"
+
+void dct64(real *out0,real *out1,real *samples)
+{
+  real bufs[64];
+
+ {
+  register int i,j;
+  register real *b1,*b2,*bs,*costab;
+
+  b1 = samples;
+  bs = bufs;
+  costab = pnts[0]+16;
+  b2 = b1 + 32;
+
+  for(i=15;i>=0;i--)
+    *bs++ = (*b1++ + *--b2); 
+  for(i=15;i>=0;i--)
+    *bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
+
+  b1 = bufs;
+  costab = pnts[1]+8;
+  b2 = b1 + 16;
+
+  {
+    for(i=7;i>=0;i--)
+      *bs++ = (*b1++ + *--b2); 
+    for(i=7;i>=0;i--)
+      *bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
+    b2 += 32;
+    costab += 8;
+    for(i=7;i>=0;i--)
+      *bs++ = (*b1++ + *--b2); 
+    for(i=7;i>=0;i--)
+      *bs++ = REAL_MUL((*b1++ - *--b2), *--costab);
+    b2 += 32;
+  }
+
+  bs = bufs;
+  costab = pnts[2];
+  b2 = b1 + 8;
+
+  for(j=2;j;j--)
+  {
+    for(i=3;i>=0;i--)
+      *bs++ = (*b1++ + *--b2); 
+    for(i=3;i>=0;i--)
+      *bs++ = REAL_MUL((*--b2 - *b1++), costab[i]);
+    b2 += 16;
+    for(i=3;i>=0;i--)
+      *bs++ = (*b1++ + *--b2); 
+    for(i=3;i>=0;i--)
+      *bs++ = REAL_MUL((*b1++ - *--b2), costab[i]);
+    b2 += 16;
+  }
+
+  b1 = bufs;
+  costab = pnts[3];
+  b2 = b1 + 4;
+
+  for(j=4;j;j--)
+  {
+    *bs++ = (*b1++ + *--b2); 
+    *bs++ = (*b1++ + *--b2);
+    *bs++ = REAL_MUL((*--b2 - *b1++), costab[1]); 
+    *bs++ = REAL_MUL((*--b2 - *b1++), costab[0]);
+    b2 += 8;
+    *bs++ = (*b1++ + *--b2); 
+    *bs++ = (*b1++ + *--b2);
+    *bs++ = REAL_MUL((*b1++ - *--b2), costab[1]);
+    *bs++ = REAL_MUL((*b1++ - *--b2), costab[0]);
+    b2 += 8;
+  }
+  bs = bufs;
+  costab = pnts[4];
+
+  for(j=8;j;j--)
+  {
+    real v0,v1;
+    v0=*b1++; v1 = *b1++;
+    *bs++ = (v0 + v1);
+    *bs++ = REAL_MUL((v0 - v1), (*costab));
+    v0=*b1++; v1 = *b1++;
+    *bs++ = (v0 + v1);
+    *bs++ = REAL_MUL((v1 - v0), (*costab));
+  }
+
+ }
+
+
+ {
+  register real *b1;
+  register int i;
+
+  for(b1=bufs,i=8;i;i--,b1+=4)
+    b1[2] += b1[3];
+
+  for(b1=bufs,i=4;i;i--,b1+=8)
+  {
+    b1[4] += b1[6];
+    b1[6] += b1[5];
+    b1[5] += b1[7];
+  }
+
+  for(b1=bufs,i=2;i;i--,b1+=16)
+  {
+    b1[8]  += b1[12];
+    b1[12] += b1[10];
+    b1[10] += b1[14];
+    b1[14] += b1[9];
+    b1[9]  += b1[13];
+    b1[13] += b1[11];
+    b1[11] += b1[15];
+  }
+ }
+
+
+  out0[0x10*16] = bufs[0];
+  out0[0x10*15] = bufs[16+0]  + bufs[16+8];
+  out0[0x10*14] = bufs[8];
+  out0[0x10*13] = bufs[16+8]  + bufs[16+4];
+  out0[0x10*12] = bufs[4];
+  out0[0x10*11] = bufs[16+4]  + bufs[16+12];
+  out0[0x10*10] = bufs[12];
+  out0[0x10* 9] = bufs[16+12] + bufs[16+2];
+  out0[0x10* 8] = bufs[2];
+  out0[0x10* 7] = bufs[16+2]  + bufs[16+10];
+  out0[0x10* 6] = bufs[10];
+  out0[0x10* 5] = bufs[16+10] + bufs[16+6];
+  out0[0x10* 4] = bufs[6];
+  out0[0x10* 3] = bufs[16+6]  + bufs[16+14];
+  out0[0x10* 2] = bufs[14];
+  out0[0x10* 1] = bufs[16+14] + bufs[16+1];
+  out0[0x10* 0] = bufs[1];
+
+  out1[0x10* 0] = bufs[1];
+  out1[0x10* 1] = bufs[16+1]  + bufs[16+9];
+  out1[0x10* 2] = bufs[9];
+  out1[0x10* 3] = bufs[16+9]  + bufs[16+5];
+  out1[0x10* 4] = bufs[5];
+  out1[0x10* 5] = bufs[16+5]  + bufs[16+13];
+  out1[0x10* 6] = bufs[13];
+  out1[0x10* 7] = bufs[16+13] + bufs[16+3];
+  out1[0x10* 8] = bufs[3];
+  out1[0x10* 9] = bufs[16+3]  + bufs[16+11];
+  out1[0x10*10] = bufs[11];
+  out1[0x10*11] = bufs[16+11] + bufs[16+7];
+  out1[0x10*12] = bufs[7];
+  out1[0x10*13] = bufs[16+7]  + bufs[16+15];
+  out1[0x10*14] = bufs[15];
+  out1[0x10*15] = bufs[16+15];
+
+}
+
+