Genesis-Plus-GX/source/system.c

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/*
Copyright (C) 1999, 2000, 2001, 2002, 2003 Charles MacDonald
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "shared.h"
#define CLOCK_NTSC 53693175
#define CLOCK_PAL 53203424
#define SND_SIZE (snd.buffer_size * sizeof(int16))
t_bitmap bitmap;
t_snd snd;
uint32 aim_m68k = 0;
uint32 count_m68k = 0;
uint32 dma_m68k = 0;
uint32 aim_z80 = 0;
uint32 count_z80 = 0;
uint16 misc68Kcycles = 488;
uint16 miscZ80cycles = 228;
uint16 lines_per_frame = 262;
double CPU_Clock = (double)CLOCK_NTSC;
void *myFM = NULL;
static int sound_tbl[312];
static int sound_inc[312];
uint8 alttiming = 0;
void m68k_run (int cyc)
{
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/* cycles remaining to run for the line */
int cyc_do = cyc - count_m68k;
/* 68k is not frozen */
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if (cyc_do > 0)
{
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/* interrupt handling */
if (vint_pending && (reg[1] & 0x20)) m68k_set_irq(6);
else if (hint_pending && (reg[0] & 0x10)) m68k_set_irq(4);
if (cyc_do > 0) m68k_execute(cyc_do);
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count_m68k += cyc_do;
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vint_pending = 0;
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}
}
void z80_run (int cyc)
{
int cyc_do = cyc - count_z80;
if (cyc_do > 0) count_z80 += z80_execute(cyc_do);
}
void m68k_freeze(int cycles)
{
extern int m68ki_remaining_cycles;
int extra_cycles = cycles - m68k_cycles_remaining();
if (extra_cycles > 0)
{
/* end of 68k execution */
m68ki_remaining_cycles = 0;
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/* extra cycles to be burned at next execution */
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count_m68k += extra_cycles;
}
else m68ki_remaining_cycles -= cycles; /* we burn some 68k cycles */
}
extern uint8 hq_fm;
int audio_init (int rate)
{
int i;
int vclk = (int)(CPU_Clock / 7.0); /* 68000 and YM2612 clock */
int zclk = (int)(CPU_Clock / 15.0); /* Z80 and SN76489 clock */
/* Clear the sound data context */
memset (&snd, 0, sizeof (snd));
/* Make sure the requested sample rate is valid */
if (!rate || ((rate < 8000) | (rate > 48000))) return (0);
/* Calculate the sound buffer size */
snd.buffer_size = (rate / vdp_rate);
snd.sample_rate = rate;
/* Allocate sound buffers */
if (FM_GENS)
{
snd.fm.gens_buffer[0] = realloc (snd.fm.gens_buffer[0], snd.buffer_size * sizeof (int));
snd.fm.gens_buffer[1] = realloc (snd.fm.gens_buffer[1], snd.buffer_size * sizeof (int));
if (!snd.fm.gens_buffer[0] || !snd.fm.gens_buffer[1]) return (-1);
memset (snd.fm.gens_buffer[0], 0, SND_SIZE*2);
memset (snd.fm.gens_buffer[1], 0, SND_SIZE*2);
}
else
{
snd.fm.buffer[0] = realloc (snd.fm.buffer[0], snd.buffer_size * sizeof (int16));
snd.fm.buffer[1] = realloc (snd.fm.buffer[1], snd.buffer_size * sizeof (int16));
if (!snd.fm.buffer[0] || !snd.fm.buffer[1]) return (-1);
memset (snd.fm.buffer[0], 0, SND_SIZE);
memset (snd.fm.buffer[1], 0, SND_SIZE);
}
snd.psg.buffer = realloc (snd.psg.buffer, snd.buffer_size * sizeof (int16));
if (!snd.psg.buffer) return (-1);
memset (snd.psg.buffer, 0, SND_SIZE);
/* Set audio enable flag */
snd.enabled = 1;
/* Initialize sound chip emulation */
if (PSG_MAME) SN76496_sh_start(zclk, 0, rate);
else
{
SN76489_Init(0, zclk, rate);
SN76489_Config(0, MUTE_ALLON, VOL_FULL, FB_SEGAVDP, SRW_SEGAVDP, 0);
}
if (FM_GENS) YM2612_Init(vclk, rate, hq_fm);
else if (!myFM) myFM = YM2612Init (0, 0, vclk, rate, 0, 0);
/* Make sound table */
for (i = 0; i < lines_per_frame; i++)
{
float p = (snd.buffer_size * i) / lines_per_frame;
float q = (snd.buffer_size * (i+1)) / lines_per_frame;
sound_tbl[i] = p;
sound_inc[i] = ((q - p) * 1000000) / snd.sample_rate;
}
return (0);
}
void system_init (void)
{
/* PAL or NTSC timings */
vdp_rate = (vdp_pal) ? 50 : 60;
lines_per_frame = (vdp_pal) ? 313 : 262;
CPU_Clock = (vdp_pal) ? (double)CLOCK_PAL : (double)CLOCK_NTSC;
miscZ80cycles = (vdp_pal) ? 227 : 228;
misc68Kcycles = (vdp_pal) ? 487 : 488;
gen_init ();
vdp_init ();
render_init ();
sound_init();
}
void system_reset (void)
{
aim_m68k = 0;
count_m68k = 0;
dma_m68k = 0;
aim_z80 = 0;
count_z80 = 0;
gen_reset ();
io_reset();
vdp_reset ();
render_reset ();
if (snd.enabled)
{
fm_reset();
if (FM_GENS)
{
memset (snd.fm.gens_buffer[0], 0, SND_SIZE*2);
memset (snd.fm.gens_buffer[1], 0, SND_SIZE*2);
}
else
{
memset (snd.fm.buffer[0], 0, SND_SIZE);
memset (snd.fm.buffer[1], 0, SND_SIZE);
}
if (!PSG_MAME) SN76489_Reset(0);
memset (snd.psg.buffer, 0, SND_SIZE);
}
}
void system_shutdown (void)
{
gen_shutdown ();
vdp_shutdown ();
render_shutdown ();
}
int system_frame (int do_skip)
{
/* update total cycles count */
dma_m68k += count_m68k;
/* reset line cycles counts */
aim_m68k = 0;
count_m68k = 0;
aim_z80 = 0;
count_z80 = 0;
lastbusreqcnt = -1000;
if (!gen_running) return 0;
/* Clear V-Blank flag */
status &= 0xFFF7;
/* Toggle even/odd flag (IM2 only) */
if (im2_flag) status ^= 0x0010;
/* Reset HCounter */
h_counter = reg[10];
/* Point to start of sound buffer */
snd.fm.lastStage = snd.fm.curStage = 0;
snd.psg.lastStage = snd.psg.curStage = 0;
/* Parse sprites for line 0 (done on line 261 or 312) */
parse_satb (0x80);
/* Line processing */
for (v_counter = 0; v_counter < lines_per_frame; v_counter ++)
{
/* update cpu cycles goal for the line */
aim_z80 += miscZ80cycles;
aim_m68k += misc68Kcycles;
/* 6-Buttons or Menacer update */
input_update();
/* If a Z80 interrupt is still pending after a scanline, cancel it */
if (zirq)
{
zirq = 0;
z80_set_irq_line(0, CLEAR_LINE);
}
/* H Int */
if (v_counter <= frame_end)
{
if(--h_counter < 0)
{
h_counter = reg[10];
hint_pending = 1;
}
}
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/* hack for Lotus 2 Recs */
if (alttiming && !do_skip)
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{
if (v_counter < frame_end) render_line(v_counter);
if (v_counter < (frame_end-1)) parse_satb(0x81 + v_counter);
}
/* H retrace */
status |= 0x0004; // HBlank = 1
m68k_run(aim_m68k - 404);
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if (!alttiming && !do_skip)
{
if (v_counter < frame_end) render_line(v_counter);
if (v_counter < (frame_end-1)) parse_satb(0x81 + v_counter);
}
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if (v_counter == frame_end)
{
/* V Retrace */
status |= 0x0008; // VBlank = 1
m68k_run(aim_m68k - 360);
if (zreset == 1 && zbusreq == 0) z80_run(aim_z80 - 168);
else count_z80 = aim_z80 - 168;
/* V Int */
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vint_pending = 1;
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status |= 0x0080;
/* Z Int */
if (zreset == 1 && zbusreq == 0)
{
zirq = 1;
z80_set_irq_line(0, ASSERT_LINE);
}
}
status &= 0xFFFB; // HBlank = 0
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/* Process end of line */
m68k_run(aim_m68k);
if (zreset == 1 && zbusreq == 0) z80_run(aim_z80);
else count_z80 = aim_z80;
/* Update sound buffers and timers */
fm_update_timers (sound_inc[v_counter]);
snd.fm.curStage = sound_tbl[v_counter];
snd.psg.curStage = sound_tbl[v_counter];
}
if (snd.enabled) audio_update ();
return gen_running;
}
#ifdef NGC
/****************************************************************************
* softdev - 09 Mar 2006
*
*
* Nintendo Gamecube Specific Mixer from here on in ...
****************************************************************************/
extern unsigned char soundbuffer[16][3840];
extern int mixbuffer;
extern double psg_preamp;
extern double fm_preamp;
extern u8 boost;
static int ll, rr;
void audio_update (void)
{
int i;
int l, r;
int16 *tempBuffer[2];
int16 *sb = (int16 *) soundbuffer[mixbuffer];
/* get remaining samples */
/* YM2612 */
if (FM_GENS)
{
int *fmBuffer[2];
fmBuffer[0] = snd.fm.gens_buffer[0] + snd.fm.lastStage;
fmBuffer[1] = snd.fm.gens_buffer[1] + snd.fm.lastStage;
YM2612_Update(fmBuffer, snd.buffer_size - snd.fm.lastStage);
}
else
{
tempBuffer[0] = snd.fm.buffer[0] + snd.fm.lastStage;
tempBuffer[1] = snd.fm.buffer[1] + snd.fm.lastStage;
YM2612UpdateOne (myFM, tempBuffer, snd.buffer_size - snd.fm.lastStage);
}
/* PSG */
tempBuffer[0] = snd.psg.buffer + snd.psg.lastStage;
if (PSG_MAME) SN76496Update (0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
else SN76489_Update(0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
/* mix samples */
for (i = 0; i < snd.buffer_size; i ++)
{
/* PSG */
l = r = (int) ((double)snd.psg.buffer[i] * psg_preamp);
if (FM_GENS)
{
l += (int) ((double)snd.fm.gens_buffer[0][i] * fm_preamp);
r += (int) ((double)snd.fm.gens_buffer[1][i] * fm_preamp);
snd.fm.gens_buffer[0][i] = 0;
snd.fm.gens_buffer[1][i] = 0;
}
else
{
l += (int) ((double)snd.fm.buffer[0][i] * fm_preamp);
r += (int) ((double)snd.fm.buffer[1][i] * fm_preamp);
}
/* single-pole low-pass filter (6 dB/octave) */
ll = (ll + l) >> 1;
rr = (rr + r) >> 1;
l = ll * boost;
r = rr * boost;
/* clipping */
if (l > 32767) l = 32767;
else if (l < -32768) l = -32768;
if (r > 32767) r = 32767;
else if (r < -32768) r = -32768;
*sb++ = l;
*sb++ = r;
}
mixbuffer++;
mixbuffer &= 0xf;
}
#else
void audio_update (void)
{
int i;
int16 acc;
int16 *tempBuffer[2];
if (FM_GENS)
{
int *fmBuffer[2];
fmBuffer[0] = snd.fm.gens_buffer[0] + snd.fm.lastStage;
fmBuffer[1] = snd.fm.gens_buffer[1] + snd.fm.lastStage;
YM2612_Update(fmBuffer, snd.buffer_size - snd.fm.lastStage);
}
else
{
tempBuffer[0] = snd.fm.buffer[0] + snd.fm.lastStage;
tempBuffer[1] = snd.fm.buffer[1] + snd.fm.lastStage;
YM2612UpdateOne (myFM, tempBuffer, snd.buffer_size - snd.fm.lastStage);
}
tempBuffer[0] = snd.psg.buffer + snd.psg.lastStage;
if (PSG_MAME) SN76496Update (0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
else SN76489_Update(0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
for (i = 0; i < snd.buffer_size; i += 1)
{
int16 psg = snd.psg.buffer[i] / 2;
acc = 0;
acc += FM_GENS ? snd.fm.gens_buffer[0][i] : snd.fm.buffer[0][i];
acc += psg;
snd.buffer[0][i] = acc;
acc = 0;
acc += FM_GENS ? snd.fm.gens_buffer[1][i] : snd.fm.buffer[1][i];
acc += psg;
snd.buffer[1][i] = acc;
if (FM_GENS)
{
snd.fm.gens_buffer[0][i] = 0;
snd.fm.gens_buffer[1][i] = 0;
}
}
}
#endif