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#include "opnaadpcm.h"
enum {
C1_START = 0x80,
C1_REC = 0x40,
C1_MEMEXT = 0x20,
C1_REPEAT = 0x10,
C1_RESET = 0x01,
C1_MASK = 0xf9,
};
enum {
C2_L = 0x80,
C2_R = 0x40,
C2_8BIT = 0x02,
C2_MASK = 0xcf,
};
static const uint8_t adpcm_table[8] = {
57, 57, 57, 57, 77, 102, 128, 153,
};
void opna_adpcm_reset(struct opna_adpcm *adpcm) {
adpcm->control1 = 0;
adpcm->control2 = 0;
adpcm->vol = 0;
adpcm->delta = 0;
adpcm->start = 0;
adpcm->end = 0;
adpcm->limit = 0;
adpcm->ramptr = 0;
adpcm->step = 0;
adpcm->ram = 0;
adpcm->acc = 0;
adpcm->prev_acc = 0;
adpcm->adpcmd = 127;
adpcm->out = 0;
leveldata_init(&adpcm->leveldata);
}
static uint32_t addr_conv(const struct opna_adpcm *adpcm, uint16_t a) {
uint32_t a32 = a;
return (adpcm->control2 & C2_8BIT) ? (a32<<6) : (a32<<3);
}
static uint32_t addr_conv_e(const struct opna_adpcm *adpcm, uint16_t a) {
uint32_t a32 = a+1;
uint32_t ret = (adpcm->control2 & C2_8BIT) ? (a32<<6) : (a32<<3);
return ret-1;
}
static void adpcm_calc(struct opna_adpcm *adpcm) {
uint32_t step = (uint32_t)adpcm->step + (uint32_t)adpcm->delta;
adpcm->step = step & 0xffff;
if (step >> 16) {
if (adpcm->ramptr == addr_conv(adpcm, adpcm->limit)) {
adpcm->ramptr = 0;
}
if (adpcm->ramptr == addr_conv_e(adpcm, adpcm->end)) {
if (adpcm->control1 & C1_REPEAT) {
adpcm->ramptr = addr_conv(adpcm, adpcm->start);
adpcm->acc = 0;
adpcm->adpcmd = 127;
adpcm->prev_acc = 0;
} else {
// TODO: set EOS
adpcm->control1 = 0;
adpcm->out = 0;
adpcm->prev_acc = 0;
}
}
uint8_t data = 0;
if (adpcm->ram) {
data = adpcm->ram[(adpcm->ramptr>>1)&(OPNA_ADPCM_RAM_SIZE-1)];
}
if (adpcm->ramptr&1) {
data &= 0x0f;
} else {
data >>= 4;
}
adpcm->ramptr++;
adpcm->ramptr &= (1<<(24+1))-1;
adpcm->prev_acc = adpcm->acc;
int32_t acc_d = (((data&7)<<1)|1);
if (data&8) acc_d = -acc_d;
int32_t acc = adpcm->acc + (acc_d * adpcm->adpcmd / 8);
if (acc < -32768) acc = -32768;
if (acc > 32767) acc = 32767;
adpcm->acc = acc;
uint32_t adpcmd = (adpcm->adpcmd * adpcm_table[data&7] / 64);
if (adpcmd < 127) adpcmd = 127;
if (adpcmd > 24576) adpcmd = 24576;
adpcm->adpcmd = adpcmd;
}
int32_t out = (int32_t)adpcm->prev_acc * (0x10000-adpcm->step);
out += (int32_t)adpcm->acc * adpcm->step;
out >>= 16;
out *= adpcm->vol;
out >>= 8;
if (out < -32768) out = -32768;
if (out > 32767) out = 32767;
adpcm->out = out;
}
void opna_adpcm_writereg(struct opna_adpcm *adpcm, unsigned reg, unsigned val) {
val &= 0xff;
if (reg < 0x100) return;
if (reg >= 0x111) return;
reg &= 0xff;
switch (reg) {
case 0x00:
adpcm->control1 = val & C1_MASK;
if (adpcm->control1 & C1_START) {
adpcm->step = 0;
adpcm->acc = 0;
adpcm->prev_acc = 0;
adpcm->out = 0;
adpcm->adpcmd = 127;
}
if (adpcm->control1 & C1_MEMEXT) {
adpcm->ramptr = addr_conv(adpcm, adpcm->start);
}
if (adpcm->control1 & C1_RESET) {
adpcm->control1 = 0;
// TODO: set BRDY
}
break;
case 0x01:
adpcm->control2 = val & C2_MASK;
break;
case 0x02:
adpcm->start &= 0xff00;
adpcm->start |= val;
break;
case 0x03:
adpcm->start &= 0x00ff;
adpcm->start |= (val<<8);
break;
case 0x04:
adpcm->end &= 0xff00;
adpcm->end |= val;
break;
case 0x05:
adpcm->end &= 0x00ff;
adpcm->end |= (val<<8);
break;
case 0x08:
// data write
if ((adpcm->control1 & (C1_START|C1_REC|C1_MEMEXT)) == (C1_REC|C1_MEMEXT)) {
// external memory write
if (adpcm->ramptr != addr_conv_e(adpcm, adpcm->end)) {
if (adpcm->ram) {
adpcm->ram[(adpcm->ramptr>>1)&(OPNA_ADPCM_RAM_SIZE-1)] = val;
}
adpcm->ramptr += 2;
} else {
// TODO: set EOS
}
}
break;
case 0x09:
adpcm->delta &= 0xff00;
adpcm->delta |= val;
break;
case 0x0a:
adpcm->delta &= 0x00ff;
adpcm->delta |= (val<<8);
break;
case 0x0b:
adpcm->vol = val;
break;
case 0x0c:
adpcm->limit &= 0xff00;
adpcm->limit |= val;
break;
case 0x0d:
adpcm->limit &= 0x00ff;
adpcm->limit |= (val<<8);
break;
}
}
void opna_adpcm_mix(struct opna_adpcm *adpcm, int16_t *buf, unsigned samples) {
unsigned level = 0;
if (!adpcm->ram || !(adpcm->control1 & C1_START)) {
leveldata_update(&adpcm->leveldata, level);
return;
}
for (unsigned i = 0; i < samples; i++) {
adpcm_calc(adpcm);
{
int clevel = adpcm->out>>1;
if (clevel < 0) clevel = -clevel;
if (((unsigned)clevel) > level) level = clevel;
}
if (!adpcm->masked) {
int32_t lo = buf[i*2+0];
int32_t ro = buf[i*2+1];
if (adpcm->control2 & C2_L) lo += (adpcm->out>>1);
if (adpcm->control2 & C2_R) ro += (adpcm->out>>1);
if (lo < INT16_MIN) lo = INT16_MIN;
if (lo > INT16_MAX) lo = INT16_MAX;
if (ro < INT16_MIN) ro = INT16_MIN;
if (ro > INT16_MAX) ro = INT16_MAX;
buf[i*2+0] = lo;
buf[i*2+1] = ro;
}
if (!(adpcm->control1 & C1_START)) return;
}
leveldata_update(&adpcm->leveldata, level);
}
void opna_adpcm_set_ram_256k(struct opna_adpcm *adpcm, void *ram) {
adpcm->ram = ram;
}
void *opna_adpcm_get_ram(struct opna_adpcm *adpcm) {
return adpcm->ram;
}
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