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rockbox/lib/rbcodec/dsp/resample.c
Aidan MacDonald 6e794c9a2d rbcodec dsp: Refactor DSP init routines, restore INIT_ATTR 
Refactor DSP init routines so there is a dedicated init function
for the stages that need it. Remove the DSP_INIT configure message.
This allows the init code to be safely marked INIT_ATTR, saving a
bit of code size, and allowing the linker to verify that there are
no unsafe references to the init routines.

Change-Id: I1702f0f579bbb300a6fe7d0e67b13aa2e9dd7f8a
2022-12-23 12:47:10 -05:00

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 Miika Pekkarinen
* Copyright (C) 2012 Michael Sevakis
* Copyright (C) 2013 Michael Giacomelli
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "rbcodecconfig.h"
#include "platform.h"
#include "fracmul.h"
#include "fixedpoint.h"
#include "dsp_proc_entry.h"
#include "dsp_misc.h"
#include "resample.h"
#include <string.h>
/**
* Linear interpolation resampling that introduces a one sample delay because
* of our inability to look into the future at the end of a frame.
*/
#if 1 /* Set to '0' to enable debug messages */
#undef DEBUGF
#define DEBUGF(...)
#endif
#define RESAMPLE_BUF_COUNT 192 /* Per channel, per DSP */
/* CODEC_IDX_AUDIO = left and right, CODEC_IDX_VOICE = mono */
static int32_t resample_out_bufs[3][RESAMPLE_BUF_COUNT] IBSS_ATTR;
/* Data for each resampler on each DSP */
static struct resample_data
{
uint32_t delta; /* 00h: Phase delta for each step in s15.16*/
uint32_t phase; /* 04h: Current phase [pos16|frac16] */
int32_t history[2][3]; /* 08h: Last samples for interpolation (L+R)
0 = oldest, 2 = newest */
/* 20h */
unsigned int frequency; /* Virtual input samplerate */
unsigned int frequency_out; /* Resampler output samplerate */
struct dsp_buffer resample_buf; /* Buffer descriptor for resampled data */
int32_t *resample_out_p[2]; /* Actual output buffer pointers */
} resample_data[DSP_COUNT] IBSS_ATTR;
/* Actual worker function. Implemented here or in target assembly code. */
int resample_hermite(struct resample_data *data, struct dsp_buffer *src,
struct dsp_buffer *dst);
static void resample_flush_data(struct resample_data *data)
{
data->phase = 0;
memset(&data->history, 0, sizeof (data->history));
}
static void resample_flush(struct dsp_proc_entry *this)
{
struct resample_data *data = (void *)this->data;
data->resample_buf.remcount = 0;
resample_flush_data(data);
}
static bool resample_new_delta(struct resample_data *data,
struct sample_format *format,
unsigned int fout)
{
unsigned int frequency = format->frequency; /* virtual samplerate */
data->frequency = frequency;
data->frequency_out = fout;
data->delta = fp_div(frequency, fout, 16);
if (frequency == data->frequency_out)
{
/* NOTE: If fully glitch-free transistions from no resampling to
resampling are desired, history should be maintained even when
not resampling. */
resample_flush_data(data);
return false;
}
return true;
}
#if !defined(CPU_COLDFIRE) && !defined(CPU_ARM)
int resample_hermite(struct resample_data *data, struct dsp_buffer *src,
struct dsp_buffer *dst)
{
int ch = src->format.num_channels - 1;
uint32_t count = MIN(src->remcount, 0x8000);
uint32_t delta = data->delta;
uint32_t phase, pos;
int32_t *d;
do
{
const int32_t *s = src->p32[ch];
d = dst->p32[ch];
int32_t *dmax = d + dst->bufcount;
/* Restore state */
phase = data->phase;
pos = phase >> 16;
pos = MIN(pos, count);
while (pos < count && d < dmax)
{
int x0, x1, x2, x3;
if (pos < 3)
{
x3 = data->history[ch][pos+0];
x2 = pos < 2 ? data->history[ch][pos+1] : s[pos-2];
x1 = pos < 1 ? data->history[ch][pos+2] : s[pos-1];
}
else
{
x3 = s[pos-3];
x2 = s[pos-2];
x1 = s[pos-1];
}
x0 = s[pos];
int32_t frac = (phase & 0xffff) << 15;
/* 4-point, 3rd-order Hermite/Catmull-Rom spline (x-form):
* c1 = -0.5*x3 + 0.5*x1
* = 0.5*(x1 - x3) <--
*
* v = x1 - x2, -v = x2 - x1
* c2 = x3 - 2.5*x2 + 2*x1 - 0.5*x0
* = x3 + 2*(x1 - x2) - 0.5*(x0 + x2)
* = x3 + 2*v - 0.5*(x0 + x2) <--
*
* c3 = -0.5*x3 + 1.5*x2 - 1.5*x1 + 0.5*x0
* = 0.5*x0 - 0.5*x3 + 0.5*(x2 - x1) + (x2 - x1)
* = 0.5*(x0 - x3 - v) - v <--
*
* polynomial coefficients */
int32_t c1 = (x1 - x3) >> 1;
int32_t v = x1 - x2;
int32_t c2 = x3 + 2*v - ((x0 + x2) >> 1);
int32_t c3 = ((x0 - x3 - v) >> 1) - v;
/* Evaluate polynomial at time 'frac'; Horner's rule. */
int32_t acc;
acc = FRACMUL(c3, frac) + c2;
acc = FRACMUL(acc, frac) + c1;
acc = FRACMUL(acc, frac) + x2;
*d++ = acc;
phase += delta;
pos = phase >> 16;
}
pos = MIN(pos, count);
/* Save delay samples for next time. Must do this even if pos was
* clamped before loop in order to keep record up to date. */
data->history[ch][0] = pos < 3 ? data->history[ch][pos+0] : s[pos-3];
data->history[ch][1] = pos < 2 ? data->history[ch][pos+1] : s[pos-2];
data->history[ch][2] = pos < 1 ? data->history[ch][pos+2] : s[pos-1];
}
while (--ch >= 0);
/* Wrap phase accumulator back to start of next frame. */
data->phase = phase - (pos << 16);
dst->remcount = d - dst->p32[0];
return pos;
}
#endif /* CPU */
/* Resample count stereo samples or stop when the destination is full.
* Updates the src buffer and changes to its own output buffer to refer to
* the resampled data. */
static void resample_process(struct dsp_proc_entry *this,
struct dsp_buffer **buf_p)
{
struct resample_data *data = (void *)this->data;
struct dsp_buffer *src = *buf_p;
struct dsp_buffer *dst = &data->resample_buf;
*buf_p = dst;
if (dst->remcount > 0)
return; /* data still remains */
dst->remcount = 0;
dst->p32[0] = data->resample_out_p[0];
dst->p32[1] = data->resample_out_p[1];
if (src->remcount > 0)
{
dst->bufcount = RESAMPLE_BUF_COUNT;
int consumed = resample_hermite(data, src, dst);
/* Advance src by consumed amount */
if (consumed > 0)
dsp_advance_buffer32(src, consumed);
}
/* else purged resample_buf */
/* Inherit in-place processed mask from source buffer */
dst->proc_mask = src->proc_mask;
}
/* Finish draining old samples then switch format or shut off */
static intptr_t resample_new_format(struct dsp_proc_entry *this,
struct dsp_config *dsp,
struct sample_format *format)
{
struct resample_data *data = (void *)this->data;
struct dsp_buffer *dst = &data->resample_buf;
if (dst->remcount > 0)
return PROC_NEW_FORMAT_TRANSITION;
DSP_PRINT_FORMAT(DSP_PROC_RESAMPLE, *format);
unsigned int frequency = data->frequency;
unsigned int fout = dsp_get_output_frequency(dsp);
bool active = dsp_proc_active(dsp, DSP_PROC_RESAMPLE);
if ((unsigned int)format->frequency != frequency ||
data->frequency_out != fout)
{
DEBUGF(" DSP_PROC_RESAMPLE- new settings: %u %u\n",
format->frequency, fout);
active = resample_new_delta(data, format, fout);
dsp_proc_activate(dsp, DSP_PROC_RESAMPLE, active);
}
/* Everything after us is fout */
dst->format = *format;
dst->format.frequency = fout;
dst->format.codec_frequency = fout;
if (active)
return PROC_NEW_FORMAT_OK;
/* No longer needed */
DEBUGF(" DSP_PROC_RESAMPLE- deactivated\n");
return PROC_NEW_FORMAT_DEACTIVATED;
}
void dsp_resample_init(struct dsp_config *dsp, unsigned int dsp_id)
{
int32_t *lbuf, *rbuf;
switch (dsp_id)
{
case CODEC_IDX_AUDIO:
lbuf = resample_out_bufs[0];
rbuf = resample_out_bufs[1];
break;
case CODEC_IDX_VOICE:
lbuf = rbuf = resample_out_bufs[2]; /* Always mono */
break;
default:
/* huh? */
DEBUGF("DSP_PROC_RESAMPLE- unknown DSP %u\n", dsp_id);
return;
}
/* Always enable resampler so that format changes may be monitored and
* it self-activated when required */
dsp_proc_enable(dsp, DSP_PROC_RESAMPLE, true);
resample_data[dsp_id].resample_out_p[0] = lbuf;
resample_data[dsp_id].resample_out_p[1] = rbuf;
}
static void resample_proc_init(struct dsp_proc_entry *this,
struct dsp_config *dsp)
{
struct resample_data *data = &resample_data[dsp_get_id(dsp)];
this->data = (intptr_t)data;
dsp_proc_set_in_place(dsp, DSP_PROC_RESAMPLE, false);
data->frequency_out = DSP_OUT_DEFAULT_HZ;
this->process = resample_process;
}
/* DSP message hook */
static intptr_t resample_configure(struct dsp_proc_entry *this,
struct dsp_config *dsp,
unsigned int setting,
intptr_t value)
{
intptr_t retval = 0;
switch (setting)
{
case DSP_FLUSH:
resample_flush(this);
break;
case DSP_PROC_INIT:
resample_proc_init(this, dsp);
break;
case DSP_PROC_CLOSE:
/* This stage should be enabled at all times */
DEBUGF("DSP_PROC_RESAMPLE- Error: Closing!\n");
break;
case DSP_PROC_NEW_FORMAT:
retval = resample_new_format(this, dsp, (struct sample_format *)value);
break;
case DSP_SET_OUT_FREQUENCY:
dsp_proc_want_format_update(dsp, DSP_PROC_RESAMPLE);
break;
}
return retval;
}
/* Database entry */
DSP_PROC_DB_ENTRY(RESAMPLE,
resample_configure);
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