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Rearrange the main synth loop a little and move some tests around for a ~5% speedup on c200, increase the output buffer size to make skips less likely, playback of simple midi files should now be mostly skip free on pp based players

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19207 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Nils Wallménius 2008-11-24 21:32:08 +00:00
parent 8486cb96c1
commit 4c43f7be0a
2 changed files with 40 additions and 28 deletions
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2
apps/plugins/midi/midiutil.h
View file

@ -21,7 +21,7 @@
#define FRACTSIZE 12
#define BUF_SIZE 8192 /* 32 kB output buffers */
#define BUF_SIZE 16384 /* 64 kB output buffers */
#define NBUF 2
#ifndef SIMULATOR

66
apps/plugins/midi/synth.c
View file

@ -262,14 +262,6 @@ void setPoint(struct SynthObject * so, int pt)
so->curOffset = 0;
}
inline void stopVoice(struct SynthObject * so)
{
if(so->state == STATE_RAMPDOWN)
return;
so->state = STATE_RAMPDOWN;
so->decay = 0;
}
static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned int samples)
{
struct GWaveform * wf;
@ -293,10 +285,13 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
const unsigned int start_loop = wf->startLoop << FRACTSIZE;
const int diff_loop = end_loop-start_loop;
bool rampdown = (so->state == STATE_RAMPDOWN);
const bool ch_9 = (so->ch == 9);
while(LIKELY(samples-- > 0))
{
/* Is voice being ramped? */
if(UNLIKELY(so->state == STATE_RAMPDOWN))
if(UNLIKELY(rampdown))
{
if(so->decay != 0) /* Ramp has been started */
{
@ -305,10 +300,10 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
if(so->decay < 10 && so->decay > -10)
so->isUsed = false;
s1=so->decay;
s2 = s1*pan;
s1 = (s1<<7) -s2;
*(out++)+=((s1 << 9) & 0xFFFF0000) | ((s2 >> 7) &0xFFFF);
s1 = so->decay;
s2 = s1 * pan;
s1 = (s1 << 7) -s2;
*(out++) += ((s1 << 9) & 0xFFFF0000) | ((s2 >> 7) &0xFFFF);
continue;
}
} else /* OK to advance voice */
@ -354,7 +349,12 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
{
cp_temp -= so->delta;
s2 = getSample((cp_temp >> FRACTSIZE)+1, wf);
stopVoice(so);
if (!rampdown) /* stop voice */
{
rampdown = true;
so->decay = 0;
}
}
/* Better, working, linear interpolation */
@ -364,12 +364,15 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
if(UNLIKELY(so->curRate == 0))
{
stopVoice(so);
if (!rampdown) /* stop voice */
{
rampdown = true;
so->decay = 0;
}
// so->isUsed = false;
}
if(LIKELY(so->ch != 9 && so->state != STATE_RAMPDOWN)) /* Stupid ADSR code... and don't do ADSR for drums */
if(LIKELY(!ch_9 && !rampdown)) /* Stupid ADSR code... and don't do ADSR for drums */
{
if(UNLIKELY(so->curOffset < so->targetOffset))
{
@ -380,9 +383,10 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
{
setPoint(so, so->curPoint+1);
}
else
else if (!rampdown) /* stop voice */
{
stopVoice(so);
rampdown = true;
so->decay = 0;
}
}
} else
@ -394,9 +398,10 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
{
setPoint(so, so->curPoint+1);
}
else
else if (!rampdown) /* stop voice */
{
stopVoice(so);
rampdown = true;
so->decay = 0;
}
}
@ -406,7 +411,11 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
if(UNLIKELY(so->curOffset < 0))
{
so->curOffset = so->targetOffset;
stopVoice(so);
if (!rampdown)
{
rampdown = true;
so->decay = 0;
}
}
s1 = s1 * (so->curOffset >> 22) >> 8;
@ -416,19 +425,22 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
s1 = s1 * volscale >> 14;
/* need to set ramp beginning */
if(UNLIKELY(so->state == STATE_RAMPDOWN && so->decay == 0))
if(UNLIKELY(rampdown && so->decay == 0))
{
so->decay = s1;
if(so->decay == 0)
so->decay = 1; /* stupid junk.. */
}
s2 = s1*pan;
s1 = (s1<<7) - s2;
*(out++)+=((s1 << 9) & 0xFFFF0000) | ((s2 >> 7) &0xFFFF);
s2 = s1 * pan;
s1 = (s1 << 7) - s2;
*(out++) += ((s1 << 9) & 0xFFFF0000) | ((s2 >> 7) &0xFFFF);
}
so->cp=cp_temp; /* store this again */
/* store these again */
if (rampdown)
so->state = STATE_RAMPDOWN;
so->cp = cp_temp;
return;
}