Consolidate all fixed point math routines in one library (FS#10400) by Jeffrey Goode

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21633 a1c6a512-1295-4272-9138-f99709370657

apps/codecs/lib/fixedpoint.h

@@ -0,0 +1,126 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id: fixedpoint.h -1   $
+ *
+ * Copyright (C) 2006 Jens Arnold
+ *
+ * Fixed point library for plugins
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef _FIXEDPOINT_H
+#define _FIXEDPOINT_H
+
+#include <inttypes.h>
+
+/** TAKEN FROM apps/dsp.h */
+/* A bunch of fixed point assembler helper macros */
+#if defined(CPU_COLDFIRE)
+/* These macros use the Coldfire EMAC extension and need the MACSR flags set
+ * to fractional mode with no rounding.
+ */
+
+/* Multiply two S.31 fractional integers and return the sign bit and the
+ * 31 most significant bits of the result.
+ */
+#define FRACMUL(x, y) \
+({ \
+    long t; \
+    asm ("mac.l    %[a], %[b], %%acc0\n\t" \
+         "movclr.l %%acc0, %[t]\n\t" \
+         : [t] "=r" (t) : [a] "r" (x), [b] "r" (y)); \
+    t; \
+})
+
+/* Multiply two S.31 fractional integers, and return the 32 most significant
+ * bits after a shift left by the constant z. NOTE: Only works for shifts of
+ * 1 to 8 on Coldfire!
+ */
+#define FRACMUL_SHL(x, y, z) \
+({ \
+    long t, t2; \
+    asm ("mac.l    %[a], %[b], %%acc0\n\t" \
+         "moveq.l  %[d], %[t]\n\t" \
+         "move.l   %%accext01, %[t2]\n\t" \
+         "and.l    %[mask], %[t2]\n\t" \
+         "lsr.l    %[t], %[t2]\n\t" \
+         "movclr.l %%acc0, %[t]\n\t" \
+         "asl.l    %[c], %[t]\n\t" \
+         "or.l     %[t2], %[t]\n\t" \
+         : [t] "=&d" (t), [t2] "=&d" (t2) \
+         : [a] "r" (x), [b] "r" (y), [mask] "d" (0xff), \
+           [c] "i" ((z)), [d] "i" (8 - (z))); \
+    t; \
+})
+
+#elif defined(CPU_ARM)
+
+/* Multiply two S.31 fractional integers and return the sign bit and the
+ * 31 most significant bits of the result.
+ */
+#define FRACMUL(x, y) \
+({ \
+    long t, t2; \
+    asm ("smull    %[t], %[t2], %[a], %[b]\n\t" \
+         "mov      %[t2], %[t2], asl #1\n\t" \
+         "orr      %[t], %[t2], %[t], lsr #31\n\t" \
+         : [t] "=&r" (t), [t2] "=&r" (t2) \
+         : [a] "r" (x), [b] "r" (y)); \
+    t; \
+})
+
+/* Multiply two S.31 fractional integers, and return the 32 most significant
+ * bits after a shift left by the constant z.
+ */
+#define FRACMUL_SHL(x, y, z) \
+({ \
+    long t, t2; \
+    asm ("smull    %[t], %[t2], %[a], %[b]\n\t" \
+         "mov      %[t2], %[t2], asl %[c]\n\t" \
+         "orr      %[t], %[t2], %[t], lsr %[d]\n\t" \
+         : [t] "=&r" (t), [t2] "=&r" (t2) \
+         : [a] "r" (x), [b] "r" (y), \
+           [c] "M" ((z) + 1), [d] "M" (31 - (z))); \
+    t; \
+})
+
+#else
+
+#define FRACMUL(x, y) (long) (((((long long) (x)) * ((long long) (y))) >> 31))
+#define FRACMUL_SHL(x, y, z) \
+((long)(((((long long) (x)) * ((long long) (y))) >> (31 - (z)))))
+
+#endif
+
+#define DIV64(x, y, z) (long)(((long long)(x) << (z))/(y))
+
+
+/** TAKEN FROM ORIGINAL fixedpoint.h */
+/* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
+ * whichever is faster for the architecture) */
+#ifdef CPU_ARM
+#define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b))))
+#else /* SH1, coldfire */
+#define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
+#endif
+
+long fsincos(unsigned long phase, long *cos);
+long fsqrt(long a, unsigned int fracbits);
+long cos_int(int val);
+long sin_int(int val);
+long flog(int x);
+
+#endif