d884af2b99
imdct and windowing are all in fixed point. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27302 a1c6a512-1295-4272-9138-f99709370657
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
#include <inttypes.h>
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#include "types.h"
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#define fixtof16(x) (float)((float)(x) / (float)(1 << 16))
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#define ftofix16(x) ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5:0.5)))
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static inline FIXED fixmulshift(FIXED x, FIXED y, int shamt)
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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 >>= shamt;
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return (int32_t)temp;
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}
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static inline void vector_fixmul_window(FIXED *dst, const FIXED *src0,
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const FIXED *src1, const FIXED *win,
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FIXED add_bias, int len)
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{
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int i, j;
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dst += len;
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win += len;
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src0+= len;
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for(i=-len, j=len-1; i<0; i++, j--) {
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FIXED s0 = src0[i];
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FIXED s1 = src1[j];
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FIXED wi = win[i];
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FIXED wj = win[j];
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dst[i] = fixmulshift(s0,-1*wj,31) - fixmulshift(s1,-1*wi,31) + (add_bias<<16);
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dst[j] = fixmulshift(s0,-1*wi,31) + fixmulshift(s1,-1*wj,31) + (add_bias<<16);
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}
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}
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static inline void vector_fixmul_scalar(FIXED *dst, const FIXED *src, FIXED mul,
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int len)
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{
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int i;
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for(i=0; i<len; i++) {
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dst[i] = fixmulshift(src[i],mul,32);
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}
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}
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