86Box/src/sound/snd_opl.c

/* Copyright holders: Sarah Walker, SA1988
   see COPYING for more details
*/
#include <stdint.h>
#include <stdlib.h>
#include "../ibm.h"
#include "../io.h"
#include "../timer.h"
#include "sound.h"
#include "snd_opl.h"
#include "snd_dbopl.h"


/*Interfaces between PCem and the actual OPL emulator*/


uint8_t opl2_read(uint16_t a, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        cycles -= (int)(isa_timing * 8);
        opl2_update2(opl);
        return opl_read(0, a);
}
void opl2_write(uint16_t a, uint8_t v, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        opl2_update2(opl);
        opl_write(0, a, v);
        opl_write(1, a, v);
}

uint8_t opl2_l_read(uint16_t a, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        cycles -= (int)(isa_timing * 8);
        opl2_update2(opl);
        return opl_read(0, a);
}
void opl2_l_write(uint16_t a, uint8_t v, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        opl2_update2(opl);
        opl_write(0, a, v);
}

uint8_t opl2_r_read(uint16_t a, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        cycles -= (int)(isa_timing * 8);
        opl2_update2(opl);
        return opl_read(1, a);
}
void opl2_r_write(uint16_t a, uint8_t v, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        opl2_update2(opl);
        opl_write(1, a, v);
}

uint8_t opl3_read(uint16_t a, void *priv)
{
        opl_t *opl = (opl_t *)priv;

        cycles -= (int)(isa_timing * 8);
        opl3_update2(opl);
        return opl_read(0, a);
}
void opl3_write(uint16_t a, uint8_t v, void *priv)
{
        opl_t *opl = (opl_t *)priv;
        
        opl3_update2(opl);
        opl_write(0, a, v);
}


void opl2_update2(opl_t *opl)
{
        if (opl->pos < sound_pos_global)
        {
                opl2_update(0, &opl->buffer[opl->pos*2], sound_pos_global - opl->pos);
                opl2_update(1, &opl->buffer[opl->pos*2 + 1], sound_pos_global - opl->pos);
                for (; opl->pos < sound_pos_global; opl->pos++)
                {
                        opl->filtbuf[0] = opl->buffer[opl->pos*2]   = (opl->buffer[opl->pos*2]   / 2);
                        opl->filtbuf[1] = opl->buffer[opl->pos*2+1] = (opl->buffer[opl->pos*2+1] / 2);
                }
        }
}

void opl3_update2(opl_t *opl)
{
        if (opl->pos < sound_pos_global)
        {
                opl3_update(0, &opl->buffer[opl->pos*2], sound_pos_global - opl->pos);
                for (; opl->pos < sound_pos_global; opl->pos++)
                {
                        opl->filtbuf[0] = opl->buffer[opl->pos*2]   = (opl->buffer[opl->pos*2]   / 2);
                        opl->filtbuf[1] = opl->buffer[opl->pos*2+1] = (opl->buffer[opl->pos*2+1] / 2);
                }
        }
}

void ym3812_timer_set_0(void *param, int timer, int64_t period)
{
        opl_t *opl = (opl_t *)param;
        
        opl->timers[0][timer] = period * TIMER_USEC * 20;
        if (!opl->timers[0][timer]) opl->timers[0][timer] = 1;
        opl->timers_enable[0][timer] = period ? 1 : 0;
}
void ym3812_timer_set_1(void *param, int timer, int64_t period)
{
        opl_t *opl = (opl_t *)param;

        opl->timers[1][timer] = period * TIMER_USEC * 20;
        if (!opl->timers[1][timer]) opl->timers[1][timer] = 1;
        opl->timers_enable[1][timer] = period ? 1 : 0;
}

void ymf262_timer_set(void *param, int timer, int64_t period)
{
        opl_t *opl = (opl_t *)param;

        opl->timers[0][timer] = period * TIMER_USEC * 20;
        if (!opl->timers[0][timer]) opl->timers[0][timer] = 1;
        opl->timers_enable[0][timer] = period ? 1 : 0;
}

static void opl_timer_callback00(void *p)
{
        opl_t *opl = (opl_t *)p;
        
        opl->timers_enable[0][0] = 0;
        opl_timer_over(0, 0);
}
static void opl_timer_callback01(void *p)
{
        opl_t *opl = (opl_t *)p;
        
        opl->timers_enable[0][1] = 0;
        opl_timer_over(0, 1);
}
static void opl_timer_callback10(void *p)
{
        opl_t *opl = (opl_t *)p;
        
        opl->timers_enable[1][0] = 0;
        opl_timer_over(1, 0);
}
static void opl_timer_callback11(void *p)
{
        opl_t *opl = (opl_t *)p;
        
        opl->timers_enable[1][1] = 0;
        opl_timer_over(1, 1);
}
        
void opl2_init(opl_t *opl)
{
        opl_init(ym3812_timer_set_0, opl, 0, 0);
        opl_init(ym3812_timer_set_1, opl, 1, 0);
        timer_add(opl_timer_callback00, &opl->timers[0][0], &opl->timers_enable[0][0], (void *)opl);
        timer_add(opl_timer_callback01, &opl->timers[0][1], &opl->timers_enable[0][1], (void *)opl);
        timer_add(opl_timer_callback10, &opl->timers[1][0], &opl->timers_enable[1][0], (void *)opl);
        timer_add(opl_timer_callback11, &opl->timers[1][1], &opl->timers_enable[1][1], (void *)opl);
}

void opl3_init(opl_t *opl)
{
        opl_init(ymf262_timer_set, opl, 0, 1);
        timer_add(opl_timer_callback00, &opl->timers[0][0], &opl->timers_enable[0][0], (void *)opl);
        timer_add(opl_timer_callback01, &opl->timers[0][1], &opl->timers_enable[0][1], (void *)opl);
}