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Minor loop optimization in libfaad's is/ms decoding.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29837 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Andree Buschmann 2011-05-08 19:36:08 +00:00
parent 7d4616ea40
commit f79769c541
2 changed files with 14 additions and 13 deletions
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18
apps/codecs/libfaad/is.c
View file

@ -32,7 +32,7 @@
#include "is.h" #include "is.h"
#ifdef FIXED_POINT #ifdef FIXED_POINT
static real_t pow05_table[] = { static real_t pow05_table[] ICONST_ATTR = {
COEF_CONST(1.68179283050743), /* 0.5^(-3/4) */ COEF_CONST(1.68179283050743), /* 0.5^(-3/4) */
COEF_CONST(1.41421356237310), /* 0.5^(-2/4) */ COEF_CONST(1.41421356237310), /* 0.5^(-2/4) */
COEF_CONST(1.18920711500272), /* 0.5^(-1/4) */ COEF_CONST(1.18920711500272), /* 0.5^(-1/4) */
@ -47,7 +47,7 @@ void is_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec,
uint16_t frame_len) uint16_t frame_len)
{ {
uint8_t g, sfb, b; uint8_t g, sfb, b;
uint16_t i; uint16_t i, k;
#ifndef FIXED_POINT #ifndef FIXED_POINT
real_t scale; real_t scale;
#else #else
@ -84,19 +84,21 @@ void is_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec,
/* Scale from left to right channel, /* Scale from left to right channel,
do not touch left channel */ do not touch left channel */
for (i = icsr->swb_offset[sfb]; i < icsr->swb_offset[sfb+1]; i++) k = (group*nshort) + icsr->swb_offset[sfb];
for (i = icsr->swb_offset[sfb]; i < icsr->swb_offset[sfb+1]; i++, k++)
{ {
#ifndef FIXED_POINT #ifndef FIXED_POINT
r_spec[(group*nshort)+i] = MUL_R(l_spec[(group*nshort)+i], scale); r_spec[k] = MUL_R(l_spec[k], scale);
#else #else
if (exp < 0) if (exp < 0)
r_spec[(group*nshort)+i] = l_spec[(group*nshort)+i] << -exp; r_spec[k] = l_spec[k] << -exp;
else else
r_spec[(group*nshort)+i] = l_spec[(group*nshort)+i] >> exp; r_spec[k] = l_spec[k] >> exp;
r_spec[(group*nshort)+i] = MUL_C(r_spec[(group*nshort)+i], pow05_table[frac + 3]);
r_spec[k] = MUL_C(r_spec[k], pow05_table[frac + 3]);
#endif #endif
if (is_intensity(icsr, g, sfb) != invert_intensity(ics, g, sfb)) if (is_intensity(icsr, g, sfb) != invert_intensity(ics, g, sfb))
r_spec[(group*nshort)+i] = -r_spec[(group*nshort)+i]; r_spec[k] = -r_spec[k];
} }
} }
} }

9
apps/codecs/libfaad/ms.c
View file

@ -41,7 +41,6 @@ void ms_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec,
uint16_t nshort = frame_len/8; uint16_t nshort = frame_len/8;
uint16_t i, k; uint16_t i, k;
real_t tmp;
if (ics->ms_mask_present >= 1) if (ics->ms_mask_present >= 1)
{ {
@ -58,12 +57,12 @@ void ms_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec,
if ((ics->ms_used[g][sfb] || ics->ms_mask_present == 2) && if ((ics->ms_used[g][sfb] || ics->ms_mask_present == 2) &&
!is_intensity(icsr, g, sfb) && !is_noise(ics, g, sfb)) !is_intensity(icsr, g, sfb) && !is_noise(ics, g, sfb))
{ {
for (i = ics->swb_offset[sfb]; i < ics->swb_offset[sfb+1]; i++) k = (group*nshort) + ics->swb_offset[sfb];
for (i = ics->swb_offset[sfb]; i < ics->swb_offset[sfb+1]; i++, k++)
{ {
k = (group*nshort) + i; /* L' = L+R, R' = L-R */
tmp = l_spec[k] - r_spec[k];
l_spec[k] = l_spec[k] + r_spec[k]; l_spec[k] = l_spec[k] + r_spec[k];
r_spec[k] = tmp; r_spec[k] = l_spec[k] - (r_spec[k]<<1);
} }
} }
} }