forked from len0rd/rockbox
4a04c47a97
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30103 a1c6a512-1295-4272-9138-f99709370657
102 lines
2.9 KiB
C
102 lines
2.9 KiB
C
#ifndef _FRACMUL_H
|
|
#define _FRACMUL_H
|
|
|
|
#include <stdint.h>
|
|
#include "gcc_extensions.h"
|
|
|
|
/** FRACTIONAL MULTIPLICATION - TAKEN FROM apps/dsp.h
|
|
* Multiply two fixed point numbers with 31 fractional bits:
|
|
* FRACMUL(x, y)
|
|
*
|
|
* Multiply two fixed point numbers with 31 fractional bits,
|
|
* then shift left by z bits:
|
|
* FRACMUL_SHL(x, y, z)
|
|
* NOTE: z must be in the range 1-8 on Coldfire targets.
|
|
*/
|
|
|
|
|
|
/* 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.
|
|
*/
|
|
static inline int32_t FRACMUL(int32_t x, int32_t y)
|
|
{
|
|
int32_t t;
|
|
asm ("mac.l %[a], %[b], %%acc0\n\t"
|
|
"movclr.l %%acc0, %[t]\n\t"
|
|
: [t] "=r" (t) : [a] "r" (x), [b] "r" (y));
|
|
return 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!
|
|
*/
|
|
static FORCE_INLINE int32_t FRACMUL_SHL(int32_t x, int32_t y, int z)
|
|
{
|
|
int32_t t, t2;
|
|
asm ("mac.l %[a], %[b], %%acc0\n\t"
|
|
"move.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] "id" ((z)), [d] "id" (8 - (z)));
|
|
return 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.
|
|
*/
|
|
static inline int32_t FRACMUL(int32_t x, int32_t y)
|
|
{
|
|
int32_t 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));
|
|
return t;
|
|
}
|
|
|
|
/* Multiply two S.31 fractional integers, and return the 32 most significant
|
|
* bits after a shift left by the constant z.
|
|
*/
|
|
static FORCE_INLINE int32_t FRACMUL_SHL(int32_t x, int32_t y, int z)
|
|
{
|
|
int32_t 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] "Mr" ((z) + 1), [d] "Mr" (31 - (z)));
|
|
return t;
|
|
}
|
|
|
|
#else
|
|
|
|
static inline int32_t FRACMUL(int32_t x, int32_t y)
|
|
{
|
|
return (int32_t) (((int64_t)x * y) >> 31);
|
|
}
|
|
|
|
static inline int32_t FRACMUL_SHL(int32_t x, int32_t y, int z)
|
|
{
|
|
return (int32_t) (((int64_t)x * y) >> (31 - z));
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif
|