1 files changed, 162 insertions, 0 deletions
diff --git a/Src/f263/idct.cpp b/Src/f263/idct.cpp
new file mode 100644
index 00000000..80eb6040
--- /dev/null
+++ b/Src/f263/idct.cpp
@@ -0,0 +1,162 @@
+#include "idct.h"
+#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */
+#define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */
+#define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */
+#define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */
+#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */
+#define W7 565  /* 2048*sqrt(2)*cos(7*pi/16) */
+
+
+short IDCT::iclip[1024];
+short *IDCT::iclp=0;
+bool IDCT::initted = false;
+
+
+/* row (horizontal) IDCT
+ *
+ *           7                       pi         1
+ * dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l )
+ *          l=0                      8          2
+ *
+ * where: c[0]    = 128
+ *        c[1..7] = 128*sqrt(2)
+ */
+
+void IDCT::idctrow(short *blk)
+{
+	int x0, x1, x2, x3, x4, x5, x6, x7, x8;
+
+	/* shortcut */
+	if (!((x1 = blk[4]<<11) | (x2 = blk[6]) | (x3 = blk[2]) |
+	      (x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3])))
+	{
+		blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3;
+		return;
+	}
+
+	x0 = (blk[0]<<11) + 128; /* for proper rounding in the fourth stage */
+
+	/* first stage */
+	x8 = W7*(x4+x5);
+	x4 = x8 + (W1-W7)*x4;
+	x5 = x8 - (W1+W7)*x5;
+	x8 = W3*(x6+x7);
+	x6 = x8 - (W3-W5)*x6;
+	x7 = x8 - (W3+W5)*x7;
+
+	/* second stage */
+	x8 = x0 + x1;
+	x0 -= x1;
+	x1 = W6*(x3+x2);
+	x2 = x1 - (W2+W6)*x2;
+	x3 = x1 + (W2-W6)*x3;
+	x1 = x4 + x6;
+	x4 -= x6;
+	x6 = x5 + x7;
+	x5 -= x7;
+
+	/* third stage */
+	x7 = x8 + x3;
+	x8 -= x3;
+	x3 = x0 + x2;
+	x0 -= x2;
+	x2 = (181*(x4+x5)+128)>>8;
+	x4 = (181*(x4-x5)+128)>>8;
+
+	/* fourth stage */
+	blk[0] = (x7+x1)>>8;
+	blk[1] = (x3+x2)>>8;
+	blk[2] = (x0+x4)>>8;
+	blk[3] = (x8+x6)>>8;
+	blk[4] = (x8-x6)>>8;
+	blk[5] = (x0-x4)>>8;
+	blk[6] = (x3-x2)>>8;
+	blk[7] = (x7-x1)>>8;
+}
+
+/* column (vertical) IDCT
+ *
+ *             7                         pi         1
+ * dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l )
+ *            l=0                        8          2
+ *
+ * where: c[0]    = 1/1024
+ *        c[1..7] = (1/1024)*sqrt(2)
+ */
+void IDCT::idctcol(short *blk)
+{
+	int x0, x1, x2, x3, x4, x5, x6, x7, x8;
+
+	/* shortcut */
+	if (!((x1 = (blk[8*4]<<8)) | (x2 = blk[8*6]) | (x3 = blk[8*2]) |
+	      (x4 = blk[8*1]) | (x5 = blk[8*7]) | (x6 = blk[8*5]) | (x7 = blk[8*3])))
+	{
+		blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]=blk[8*5]=blk[8*6]=blk[8*7]=
+		                                      iclp[(blk[8*0]+32)>>6];
+		return;
+	}
+
+	x0 = (blk[8*0]<<8) + 8192;
+
+	/* first stage */
+	x8 = W7*(x4+x5) + 4;
+	x4 = (x8+(W1-W7)*x4)>>3;
+	x5 = (x8-(W1+W7)*x5)>>3;
+	x8 = W3*(x6+x7) + 4;
+	x6 = (x8-(W3-W5)*x6)>>3;
+	x7 = (x8-(W3+W5)*x7)>>3;
+
+	/* second stage */
+	x8 = x0 + x1;
+	x0 -= x1;
+	x1 = W6*(x3+x2) + 4;
+	x2 = (x1-(W2+W6)*x2)>>3;
+	x3 = (x1+(W2-W6)*x3)>>3;
+	x1 = x4 + x6;
+	x4 -= x6;
+	x6 = x5 + x7;
+	x5 -= x7;
+
+	/* third stage */
+	x7 = x8 + x3;
+	x8 -= x3;
+	x3 = x0 + x2;
+	x0 -= x2;
+	x2 = (181*(x4+x5)+128)>>8;
+	x4 = (181*(x4-x5)+128)>>8;
+
+	/* fourth stage */
+	blk[8*0] = iclp[(x7+x1)>>14];
+	blk[8*1] = iclp[(x3+x2)>>14];
+	blk[8*2] = iclp[(x0+x4)>>14];
+	blk[8*3] = iclp[(x8+x6)>>14];
+	blk[8*4] = iclp[(x8-x6)>>14];
+	blk[8*5] = iclp[(x0-x4)>>14];
+	blk[8*6] = iclp[(x3-x2)>>14];
+	blk[8*7] = iclp[(x7-x1)>>14];
+}
+
+/* two dimensional inverse discrete cosine transform */
+void IDCT::idct(short *block)
+{
+	int i;
+
+	for (i=0; i<8; i++)
+		idctrow(block+8*i);
+
+	for (i=0; i<8; i++)
+		idctcol(block+i);
+}
+
+void IDCT::init()
+{
+	if (!initted)
+	{
+		int i;
+
+		iclp = iclip+512;
+		for (i= -512; i<512; i++)
+			iclp[i] = (i<-256) ? -256 : ((i>255) ? 255 : i);
+		initted=true;
+	}
+}