/*
* PicoDrive
* (C) notaz, 2008
+ * (C) irixxxx, 2024
*
* This work is licensed under the terms of MAME license.
* See COPYING file in the top-level directory.
// 0x2f8 - 0x3f3
picohw_state PicoPicohw;
-static int prev_line_cnt_irq3 = 0, prev_line_cnt_irq5 = 0;
-static int fifo_bytes_line = (16000<<16)/60/262/2;
-static const int guessed_rates[] = { 8000, 14000, 12000, 14000, 16000, 18000, 16000, 16000 }; // ?
-
-#define PICOHW_FIFO_IRQ_THRESHOLD 12
PICO_INTERNAL void PicoReratePico(void)
{
- int rate = guessed_rates[PicoPicohw.r12 & 7];
- if (Pico.m.pal)
- fifo_bytes_line = (rate<<16)/50/313/2;
- else fifo_bytes_line = (rate<<16)/60/262/2;
- PicoPicoPCMRerate(rate);
+ PicoPicoPCMRerate();
}
static void PicoLinePico(void)
{
- PicoPicohw.line_counter++;
-
-#if 1
- if ((PicoPicohw.r12 & 0x4003) && PicoPicohw.line_counter - prev_line_cnt_irq3 > 200) {
- prev_line_cnt_irq3 = PicoPicohw.line_counter;
- // just a guess/hack, allows 101 Dalmantians to boot
- elprintf(EL_PICOHW, "irq3");
- SekInterrupt(3);
- return;
- }
-#endif
-
- if (PicoPicohw.fifo_bytes > 0)
- {
- PicoPicohw.fifo_line_bytes += fifo_bytes_line;
- if (PicoPicohw.fifo_line_bytes >= (1<<16)) {
- PicoPicohw.fifo_bytes -= PicoPicohw.fifo_line_bytes >> 16;
- PicoPicohw.fifo_line_bytes &= 0xffff;
- if (PicoPicohw.fifo_bytes < 0)
- PicoPicohw.fifo_bytes = 0;
- }
- }
- else
- PicoPicohw.fifo_line_bytes = 0;
-
-#if 1
- if (PicoPicohw.fifo_bytes_prev >= PICOHW_FIFO_IRQ_THRESHOLD &&
- PicoPicohw.fifo_bytes < PICOHW_FIFO_IRQ_THRESHOLD) {
- prev_line_cnt_irq3 = PicoPicohw.line_counter; // ?
- elprintf(EL_PICOHW, "irq3, fb=%i", PicoPicohw.fifo_bytes);
- SekInterrupt(3);
- }
- PicoPicohw.fifo_bytes_prev = PicoPicohw.fifo_bytes;
-#endif
-
-#if 0
- if (PicoPicohw.line_counter - prev_line_cnt_irq5 > 512) {
- prev_line_cnt_irq5 = PicoPicohw.line_counter;
- elprintf(EL_PICOHW, "irq5");
- SekInterrupt(5);
- }
-#endif
+ // update sound so that irq for FIFO refill is generated
+ if ((PicoPicohw.fifo_bytes | !PicoPicoPCMBusyN()) && (Pico.m.scanline & 7) == 7)
+ PsndDoPCM(cycles_68k_to_z80(SekCyclesDone() - Pico.t.m68c_frame_start));
}
static void PicoResetPico(void)
{
- PicoPicoPCMReset();
+ PicoPicoPCMResetN(1);
+ PicoPicoPCMStartN(1);
PicoPicohw.xpcm_ptr = PicoPicohw.xpcm_buffer;
+ PicoPicohw.fifo_bytes = 0;
+ PicoPicohw.r12 = 0;
+
+ PicoPicoPCMIrqEn(0);
+ PicoPicoPCMFilter(0);
+ PicoPicoPCMGain(8);
+
+ // map version register
+ PicoDetectRegion();
+ switch (Pico.m.hardware >> 6) {
+ case 0: PicoPicohw.r1 = 0x40; break; // JP NTSC
+ case 1: PicoPicohw.r1 = 0x00; break; // JP PAL
+ case 2: PicoPicohw.r1 = 0x60; break; // US
+ case 3: PicoPicohw.r1 = 0x20; break; // EU
+ }
}
PICO_INTERNAL void PicoInitPico(void)
memset(&PicoPicohw, 0, sizeof(PicoPicohw));
PicoPicohw.pen_pos[0] = 0x03c + 320/2;
PicoPicohw.pen_pos[1] = 0x200 + 240/2;
- prev_line_cnt_irq3 = prev_line_cnt_irq5 = 0;
-
- // map version register
- PicoDetectRegion();
- switch (Pico.m.hardware >> 6) {
- case 0: PicoPicohw.r1 = 0x40; break;
- case 1: PicoPicohw.r1 = 0x00; break;
- case 2: PicoPicohw.r1 = 0x60; break;
- case 3: PicoPicohw.r1 = 0x20; break;
- }
}
-
/*
* PicoDrive
* (C) notaz, 2008
+ * (C) irixxxx, 2024
*
* This work is licensed under the terms of MAME license.
* See COPYING file in the top-level directory.
*
- * The following ADPCM algorithm was stolen from MAME aica driver.
- * I'm quite sure it's not the right one, but it's the
- * best sounding of the ones that I tried.
+ * The following ADPCM algorithm was derived from MAME upd7759 driver.
*/
+#include <math.h>
#include "../pico_int.h"
-#define ADPCMSHIFT 8
-#define ADFIX(f) (int) ((double)f * (double)(1<<ADPCMSHIFT))
-
/* limitter */
-#define Limit(val, max, min) { \
- if ( val > max ) val = max; \
- else if ( val < min ) val = min; \
-}
+#define Limit(val, max, min) \
+ (val > max ? max : val < min ? min : val)
+
+#define ADPCM_CLOCK (1280000/4)
+
+#define FIFO_IRQ_THRESHOLD 16
-static const int TableQuant[8] =
+static const int step_deltas[16][16] =
{
- ADFIX(0.8984375),
- ADFIX(0.8984375),
- ADFIX(0.8984375),
- ADFIX(0.8984375),
- ADFIX(1.19921875),
- ADFIX(1.59765625),
- ADFIX(2.0),
- ADFIX(2.3984375)
+ { 0, 0, 1, 2, 3, 5, 7, 10, 0, 0, -1, -2, -3, -5, -7, -10 },
+ { 0, 1, 2, 3, 4, 6, 8, 13, 0, -1, -2, -3, -4, -6, -8, -13 },
+ { 0, 1, 2, 4, 5, 7, 10, 15, 0, -1, -2, -4, -5, -7, -10, -15 },
+ { 0, 1, 3, 4, 6, 9, 13, 19, 0, -1, -3, -4, -6, -9, -13, -19 },
+ { 0, 2, 3, 5, 8, 11, 15, 23, 0, -2, -3, -5, -8, -11, -15, -23 },
+ { 0, 2, 4, 7, 10, 14, 19, 29, 0, -2, -4, -7, -10, -14, -19, -29 },
+ { 0, 3, 5, 8, 12, 16, 22, 33, 0, -3, -5, -8, -12, -16, -22, -33 },
+ { 1, 4, 7, 10, 15, 20, 29, 43, -1, -4, -7, -10, -15, -20, -29, -43 },
+ { 1, 4, 8, 13, 18, 25, 35, 53, -1, -4, -8, -13, -18, -25, -35, -53 },
+ { 1, 6, 10, 16, 22, 31, 43, 64, -1, -6, -10, -16, -22, -31, -43, -64 },
+ { 2, 7, 12, 19, 27, 37, 51, 76, -2, -7, -12, -19, -27, -37, -51, -76 },
+ { 2, 9, 16, 24, 34, 46, 64, 96, -2, -9, -16, -24, -34, -46, -64, -96 },
+ { 3, 11, 19, 29, 41, 57, 79, 117, -3, -11, -19, -29, -41, -57, -79, -117 },
+ { 4, 13, 24, 36, 50, 69, 96, 143, -4, -13, -24, -36, -50, -69, -96, -143 },
+ { 4, 16, 29, 44, 62, 85, 118, 175, -4, -16, -29, -44, -62, -85, -118, -175 },
+ { 6, 20, 36, 54, 76, 104, 144, 214, -6, -20, -36, -54, -76, -104, -144, -214 },
};
-// changed using trial and error..
-//static const int quant_mul[16] = { 1, 3, 5, 7, 9, 11, 13, 15, -1, -3, -5, -7, -9, -11, -13, -15 };
-static const int quant_mul[16] = { 1, 3, 5, 7, 9, 11, 13, -1, -1, -3, -5, -7, -9, -11, -13, -15 };
+static const int state_deltas[16] = { -1, -1, 0, 0, 1, 2, 2, 3, -1, -1, 0, 0, 1, 2, 2, 3 };
+
+static int sample = 0, state = 0;
+static s32 stepsamples = (44100LL<<16)/ADPCM_CLOCK;
+static s32 samplepos;
+static int samplegain;
+
+static int startpin, irqenable;
+static enum { RESET, START, HDR, COUNT } portstate = RESET;
+static int rate, silence, nibbles, highlow, cache;
+
+
+// SEGA Pico specific filtering
+
+#define QB 16 // mantissa bits
+#define FP(f) (int)((f)*(1<<QB)) // convert to fixpoint
+
+static struct iir2 { // 2nd order IIR
+ s32 a[2], gain; // coefficients
+ s32 y[3], x[3]; // filter history
+} filters[4];
+static struct iir2 *filter;
+
+
+static void PicoPicoFilterCoeff(struct iir2 *iir, int cutoff, int rate)
+{
+ if (cutoff >= rate/2) {
+ memset(iir, 0, sizeof(*iir));
+ return;
+ }
+
+ // compute 2nd order butterworth filter coefficients
+ double a = 1 / tan(M_PI * cutoff / rate);
+ double axa = a*a;
+ double gain = 1/(1 + M_SQRT2*a + axa);
+ iir->gain = FP(gain);
+ iir->a[0] = FP(2 * (axa-1) * gain);
+ iir->a[1] = FP(-(1 - M_SQRT2*a + axa) * gain);
+}
+
+static int PicoPicoFilterApply(struct iir2 *iir, int sample)
+{
+ if (!iir)
+ return sample;
+
+ iir->x[0] = iir->x[1]; iir->x[1] = iir->x[2];
+ iir->x[2] = sample * iir->gain; // Qb
+ iir->y[0] = iir->y[1]; iir->y[1] = iir->y[2];
+ iir->y[2] = (iir->x[0] + 2*iir->x[1] + iir->x[2]
+ + iir->y[0]*iir->a[1] + iir->y[1]*iir->a[0]) >> QB;
+ return iir->y[2];
+}
+
+
+// pin functions, N designating a negated pin
+
+PICO_INTERNAL void PicoPicoPCMResetN(int pin)
+{
+ if (!pin) {
+ portstate = RESET;
+ sample = samplepos = state = 0;
+ portstate = nibbles = silence = 0;
+ } else if (portstate == RESET)
+ portstate = START;
+}
+
+PICO_INTERNAL void PicoPicoPCMStartN(int pin)
+{
+ startpin = pin;
+}
+
+PICO_INTERNAL int PicoPicoPCMBusyN(void)
+{
+ return (portstate <= START);
+}
+
+
+// configuration functions
+
+PICO_INTERNAL void PicoPicoPCMRerate(void)
+{
+ // output samples per chip clock
+ stepsamples = ((u64)PicoIn.sndRate<<16)/ADPCM_CLOCK;
-static int sample = 0, quant = 0, sgn = 0;
-static int stepsamples = (44100<<10)/16000;
+ // compute filter coefficients, cutoff at half the ADPCM sample rate
+ PicoPicoFilterCoeff(&filters[1], 5000/2, PicoIn.sndRate); // 5-6 KHz
+ PicoPicoFilterCoeff(&filters[2], 8000/2, PicoIn.sndRate); // 8-12 KHz
+ PicoPicoFilterCoeff(&filters[3], 14000/2, PicoIn.sndRate); // 14-16 KHz
+}
+PICO_INTERNAL void PicoPicoPCMGain(int gain)
+{
+ samplegain = gain*4;
+}
+
+PICO_INTERNAL void PicoPicoPCMFilter(int index)
+{
+ filter = filters+index;
+ if (filter->a[0] == 0)
+ filter = NULL;
+}
-PICO_INTERNAL void PicoPicoPCMReset(void)
+PICO_INTERNAL void PicoPicoPCMIrqEn(int enable)
{
- sample = sgn = 0;
- quant = 0x7f;
- memset(PicoPicohw.xpcm_buffer, 0, sizeof(PicoPicohw.xpcm_buffer));
+ irqenable = (enable ? 3 : 0);
}
-PICO_INTERNAL void PicoPicoPCMRerate(int xpcm_rate)
+// TODO need an interupt pending mask?
+PICO_INTERNAL int PicoPicoIrqAck(int level)
{
- stepsamples = (PicoIn.sndRate<<10)/xpcm_rate;
+ return (PicoPicohw.fifo_bytes < FIFO_IRQ_THRESHOLD && level != irqenable ? irqenable : 0);
}
-#define XSHIFT 6
-#define do_sample() \
+// adpcm operation
+
+#define apply_filter(v) PicoPicoFilterApply(filter, v)
+
+#define do_sample(nibble) \
{ \
- int delta = quant * quant_mul[srcval] >> XSHIFT; \
- sample += delta - (delta >> 2); /* 3/4 */ \
- quant = (quant * TableQuant[srcval&7]) >> ADPCMSHIFT; \
- Limit(quant, 0x6000, 0x7f); \
- Limit(sample, 32767*3/4, -32768*3/4); \
+ sample += step_deltas[state][nibble]; \
+ state += state_deltas[nibble]; \
+ state = (state < 0 ? 0 : state > 15 ? 15 : state); \
+}
+
+#define write_sample(buffer, length, stereo) \
+{ \
+ while (samplepos > 0 && length > 0) { \
+ int val = Limit(samplegain*sample, 16383, -16384); \
+ samplepos -= 1<<16; \
+ length --; \
+ if (buffer) { \
+ int out = apply_filter(val); \
+ *buffer++ += out; \
+ if (stereo) *buffer++ += out; \
+ } \
+ } \
}
PICO_INTERNAL void PicoPicoPCMUpdate(short *buffer, int length, int stereo)
{
unsigned char *src = PicoPicohw.xpcm_buffer;
unsigned char *lim = PicoPicohw.xpcm_ptr;
- int srcval, needsamples = 0;
+ int srcval, irq = 0;
- if (src == lim) goto end;
+ // leftover partial sample from last run
+ write_sample(buffer, length, stereo);
- for (; length > 0 && src < lim; src++)
+ // loop over FIFO data, generating ADPCM samples
+ while (length > 0 && src < lim)
{
- srcval = *src >> 4;
- do_sample();
+ if (silence > 0) {
+ silence --;
+ sample = 0;
+ samplepos += stepsamples*256;
- if (buffer)
- for (needsamples += stepsamples; needsamples > (1<<10) && length > 0; needsamples -= (1<<10), length--) {
- *buffer++ += sample;
- if (stereo) { buffer[0] = buffer[-1]; buffer++; }
- }
+ } else if (nibbles > 0) {
+ nibbles --;
+
+ if (highlow)
+ cache = *src++;
+ else
+ cache <<= 4;
+ highlow = !highlow;
- srcval = *src & 0xf;
- do_sample();
+ do_sample((cache & 0xf0) >> 4);
+ samplepos += stepsamples*rate;
- if (buffer)
- for (needsamples += stepsamples; needsamples > (1<<10) && length > 0; needsamples -= (1<<10), length--) {
- *buffer++ += sample;
- if (stereo) { buffer[0] = buffer[-1]; buffer++; }
+ } else switch (portstate) {
+ case RESET:
+ sample = 0;
+ samplepos += length<<16;
+ break;
+ case START:
+ if (startpin) {
+ if (*src)
+ portstate ++;
+ else // kill 0x00 bytes at stream start
+ src ++;
+ } else {
+ sample = 0;
+ samplepos += length<<16;
+ }
+ break;
+ case HDR:
+ srcval = *src++;
+ nibbles = silence = rate = 0;
+ highlow = 1;
+ if (srcval == 0) { // terminator
+ // HACK, kill leftover odd byte to avoid restart (Minna de Odorou)
+ if (lim-src == 1) src++;
+ portstate = START;
+ } else switch (srcval >> 6) {
+ case 0: silence = (srcval & 0x3f) + 1; break;
+ case 1: rate = (srcval & 0x3f) + 1; nibbles = 256; break;
+ case 2: rate = (srcval & 0x3f) + 1; portstate = COUNT; break;
+ case 3: break;
+ }
+ break;
+ case COUNT:
+ nibbles = *src++ + 1; portstate = HDR;
+ break;
}
- // lame normalization stuff, needed due to wrong adpcm algo
- sgn += (sample < 0) ? -1 : 1;
- if (sgn < -16 || sgn > 16) sample -= sample >> 5;
+ write_sample(buffer, length, stereo);
}
- if (src < lim) {
+ // buffer cleanup, generate irq if lowwater reached
+ if (src < lim && src != PicoPicohw.xpcm_buffer) {
int di = lim - src;
memmove(PicoPicohw.xpcm_buffer, src, di);
PicoPicohw.xpcm_ptr = PicoPicohw.xpcm_buffer + di;
elprintf(EL_PICOHW, "xpcm update: over %i", di);
- // adjust fifo
+
+ if (!irq && di < FIFO_IRQ_THRESHOLD)
+ irq = irqenable;
PicoPicohw.fifo_bytes = di;
- return;
- }
+ } else if (src == lim && src != PicoPicohw.xpcm_buffer) {
+ PicoPicohw.xpcm_ptr = PicoPicohw.xpcm_buffer;
+ elprintf(EL_PICOHW, "xpcm update: under %i", length);
- elprintf(EL_PICOHW, "xpcm update: under %i", length);
- PicoPicohw.xpcm_ptr = PicoPicohw.xpcm_buffer;
+ if (!irq)
+ irq = irqenable;
+ PicoPicohw.fifo_bytes = 0;
+ }
-end:
- if (buffer && stereo)
- // still must expand SN76496 to stereo
- for (; length > 0; buffer+=2, length--)
- buffer[1] = buffer[0];
+ // TODO need an IRQ mask somewhere to avoid loosing one in cases of HINT/VINT
+ if (irq && SekIrqLevel != irq) {
+ elprintf(EL_PICOHW, "irq%d", irq);
+ if (SekIrqLevel < irq)
+ SekInterrupt(irq);
+ }
- sample = sgn = 0;
- quant = 0x7f;
+ if (buffer && length) {
+ // for underflow, use last sample to avoid clicks
+ int val = Limit(samplegain*sample, 16383, -16384);
+ while (length--) {
+ int out = apply_filter(val);
+ *buffer++ += out;
+ if (stereo) *buffer++ += out;
+ }
+ }
}
-
notaz.gp2x.de / picodrive.git / commitdiff