diff options
Diffstat (limited to 'src/chips/ym3812_lle/nopl2.c')
| -rw-r--r-- | src/chips/ym3812_lle/nopl2.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/src/chips/ym3812_lle/nopl2.c b/src/chips/ym3812_lle/nopl2.c new file mode 100644 index 0000000..7dfb8dd --- /dev/null +++ b/src/chips/ym3812_lle/nopl2.c @@ -0,0 +1,242 @@ +/* + * Copyright (C) 2023 nukeykt + * + * This file is part of YM3812-LLE. + * + * 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 program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * YM3812 emulator + * Thanks: + * Travis Goodspeed: + * YM3812 decap and die shot + * + */ + +#include "nuked_fmopl2.h" +#include <stdint.h> +#include <stdlib.h> +#include "nopl2.h" + +#define OPL_WRITEBUF_SIZE 2048 +#define OPL_WRITEBUF_DELAY 1 +#define RSM_FRAC 10 + +typedef struct _opl2_writebuf { + uint64_t time; + uint8_t reg; + uint8_t data; +} opl2_writebuf; + +typedef struct { + fmopl2_t chip; + + int sample; + int o_sy; + int shifter; + int o_sh; + + int32_t rateratio; + int32_t samplecnt; + int oldsample; + + uint64_t writebuf_samplecnt; + uint32_t writebuf_cur; + uint32_t writebuf_last; + uint64_t writebuf_lasttime; + opl2_writebuf writebuf[OPL_WRITEBUF_SIZE]; +} nopl2_t; + +void nopl2_cycle(nopl2_t *chip) +{ + int i, mant, shift; + + for (i = 0; i < 144; i++) + { + chip->chip.input.mclk = i & 1; + FMOPL2_Clock(&chip->chip); + + if (!chip->o_sy && chip->chip.o_sy) + { + + if (chip->o_sh && !chip->chip.o_sh) + { + mant = chip->shifter & 0x3ff; + mant -= 512; + shift = (chip->shifter >> 10) & 7; + + chip->sample = 0; + if (shift) + { + shift--; + chip->sample = mant << shift; + } + } + chip->shifter = (chip->shifter >> 1) | (chip->chip.o_mo << 12); + + chip->o_sh = chip->chip.o_sh; + } + + chip->o_sy = chip->chip.o_sy; + } +} + +void *nopl2_init(int clock, int samplerate) +{ + nopl2_t *chip = calloc(1, sizeof(nopl2_t)); + nopl2_set_rate(chip, clock, samplerate); + return chip; +} + +void nopl2_set_rate(void* chip_p, int clock, int samplerate) +{ + nopl2_t *chip = (nopl2_t*)chip_p; + + chip->chip.input.cs = 0; + chip->chip.input.ic = 1; + chip->chip.input.rd = 1; + chip->chip.input.wr = 1; + + samplerate *= 1; + + chip->rateratio = ((samplerate << RSM_FRAC) * (int64_t)72) / clock; + + /* printf("%i %i\n", clock, samplerate); */ + + nopl2_reset(chip); +} + +void nopl2_shutdown(void *chip) +{ + free(chip); +} + +void nopl2_reset(void *chip) +{ + nopl2_t* chip2 = chip; + int i = 0; + + chip2->chip.input.ic = 0; + for (i = 0; i < 100; i++) + { + nopl2_cycle(chip2); + } + chip2->chip.input.ic = 1; + for (i = 0; i < 100; i++) + { + nopl2_cycle(chip2); + } + +} + +void nopl2_write2(nopl2_t *chip, int port, int val) +{ + chip->chip.input.address = port; + chip->chip.input.data_i = val; + chip->chip.input.wr = 0; + FMOPL2_Clock(&chip->chip); /* propagate */ + chip->chip.input.wr = 1; + FMOPL2_Clock(&chip->chip); /* propagate */ +} + +void nopl2_getsample(void *chip, short *sndptr, int numsamples) +{ + nopl2_t* chip2 = chip; + int i, buf; + short *p = sndptr; + opl2_writebuf* writebuf; + + for (i = 0; i < numsamples; i++) + { + while (chip2->samplecnt >= chip2->rateratio) + { + chip2->oldsample = chip2->sample; + nopl2_cycle(chip2); + + while ((writebuf = &chip2->writebuf[chip2->writebuf_cur]), writebuf->time <= chip2->writebuf_samplecnt) + { + if (!(writebuf->reg & 2)) + break; + + writebuf->reg &= 1; + nopl2_write2(chip2, writebuf->reg, writebuf->data); + chip2->writebuf_cur = (chip2->writebuf_cur + 1) % OPL_WRITEBUF_SIZE; + } + chip2->writebuf_samplecnt++; + chip2->samplecnt -= chip2->rateratio; + } + + buf = (chip2->oldsample * (chip2->rateratio - chip2->samplecnt) + + chip2->sample * chip2->samplecnt) / chip2->rateratio; + *p++ = buf; + *p++ = buf; + } +} + +void nopl2_getsample_one_native(void *chip, short *sndptr) +{ + nopl2_t* chip2 = chip; + short *p = sndptr; + opl2_writebuf* writebuf; + + chip2->oldsample = chip2->sample; + nopl2_cycle(chip2); + + while ((writebuf = &chip2->writebuf[chip2->writebuf_cur]), writebuf->time <= chip2->writebuf_samplecnt) + { + if (!(writebuf->reg & 2)) + break; + + writebuf->reg &= 1; + nopl2_write2(chip2, writebuf->reg, writebuf->data); + chip2->writebuf_cur = (chip2->writebuf_cur + 1) % OPL_WRITEBUF_SIZE; + } + + chip2->writebuf_samplecnt++; + chip2->samplecnt -= chip2->rateratio; + chip2->samplecnt += 1 << RSM_FRAC; + + *p++ = chip2->sample; + *p++ = chip2->sample; +} + +void nopl2_write(void *chip, int port, int val) +{ + nopl2_t* chip2 = chip; + uint64_t time1, time2; + opl2_writebuf *writebuf; + uint32_t writebuf_last; + + writebuf_last = chip2->writebuf_last; + writebuf = &chip2->writebuf[writebuf_last]; + + if (writebuf->reg & 2) + { + nopl2_write2(chip2, writebuf->reg & 1, writebuf->data); + nopl2_cycle(chip2); + + chip2->writebuf_cur = (writebuf_last + 1) % OPL_WRITEBUF_SIZE; + chip2->writebuf_samplecnt = writebuf->time; + } + + writebuf->reg = port | 2; + writebuf->data = val; + time1 = chip2->writebuf_lasttime + OPL_WRITEBUF_DELAY; + time2 = chip2->writebuf_samplecnt; + + if (time1 < time2) + { + time1 = time2; + } + + writebuf->time = time1; + chip2->writebuf_lasttime = time1; + chip2->writebuf_last = (writebuf_last + 1) % OPL_WRITEBUF_SIZE; +} |