57461d7c4f
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24665 a1c6a512-1295-4272-9138-f99709370657
93 lines
3 KiB
C
93 lines
3 KiB
C
#include <stdlib.h>
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#include <inttypes.h>
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/* Macros for converting between various fixed-point representations and floating point. */
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#define ONE_16 (1L << 16)
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#define fixtof64(x) (float)((float)(x) / (float)(1 << 16)) //does not work on int64_t!
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#define ftofix32(x) ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5 : 0.5)))
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#define ftofix31(x) ((int32_t)((x) * (float)(1 << 31) + ((x) < 0 ? -0.5 : 0.5)))
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#define fix31tof64(x) (float)((float)(x) / (float)(1 << 31))
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/* Fixed point math routines for use in atrac3.c */
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#if defined(CPU_ARM)
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#define fixmul16(X,Y) \
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({ \
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int32_t low; \
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int32_t high; \
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asm volatile ( /* calculates: result = (X*Y)>>16 */ \
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"smull %0,%1,%2,%3 \n\t" /* 64 = 32x32 multiply */ \
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"mov %0, %0, lsr #16 \n\t" /* %0 = %0 >> 16 */ \
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"orr %0, %0, %1, lsl #16 \n\t"/* result = %0 OR (%1 << 16) */ \
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: "=&r"(low), "=&r" (high) \
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: "r"(X),"r"(Y)); \
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low; \
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})
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#define fixmul31(X,Y) \
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({ \
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int32_t low; \
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int32_t high; \
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asm volatile ( /* calculates: result = (X*Y)>>31 */ \
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"smull %0,%1,%2,%3 \n\t" /* 64 = 32x32 multiply */ \
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"mov %0, %0, lsr #31 \n\t" /* %0 = %0 >> 31 */ \
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"orr %0, %0, %1, lsl #1 \n\t" /* result = %0 OR (%1 << 1) */ \
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: "=&r"(low), "=&r" (high) \
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: "r"(X),"r"(Y)); \
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low; \
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})
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#elif defined(CPU_COLDFIRE)
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#define fixmul16(X,Y) \
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({ \
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int32_t t1, t2; \
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asm volatile ( \
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"mac.l %[x],%[y],%%acc0\n\t" /* multiply */ \
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"mulu.l %[y],%[x] \n\t" /* get lower half, avoid emac stall */ \
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"movclr.l %%acc0,%[t1] \n\t" /* get higher half */ \
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"moveq.l #15,%[t2] \n\t" \
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"asl.l %[t2],%[t1] \n\t" /* hi <<= 15, plus one free */ \
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"moveq.l #16,%[t2] \n\t" \
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"lsr.l %[t2],%[x] \n\t" /* (unsigned)lo >>= 16 */ \
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"or.l %[x],%[t1] \n\t" /* combine result */ \
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: /* outputs */ \
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[t1]"=&d"(t1), \
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[t2]"=&d"(t2) \
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: /* inputs */ \
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[x] "d" ((X)), \
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[y] "d" ((Y))); \
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t1; \
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})
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#define fixmul31(X,Y) \
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({ \
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int32_t t; \
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asm volatile ( \
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"mac.l %[x], %[y], %%acc0\n\t" /* multiply */ \
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"movclr.l %%acc0, %[t]\n\t" /* get higher half as result */ \
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: [t] "=d" (t) \
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: [x] "r" ((X)), [y] "r" ((Y))); \
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t; \
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})
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#else
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static inline int32_t fixmul16(int32_t x, int32_t y)
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{
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int64_t temp;
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temp = x;
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temp *= y;
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temp >>= 16;
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return (int32_t)temp;
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}
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static inline int32_t fixmul31(int32_t x, int32_t y)
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{
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int64_t temp;
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temp = x;
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temp *= y;
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temp >>= 31; //16+31-16 = 31 bits
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return (int32_t)temp;
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}
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#endif
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