mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
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434 lines
11 KiB
C
434 lines
11 KiB
C
/*
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Copyright (C) 1999, 2000, 2001, 2002, 2003 Charles MacDonald
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "shared.h"
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#define CLOCK_NTSC 53693175
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#define CLOCK_PAL 53203424
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#define SND_SIZE (snd.buffer_size * sizeof(int16))
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t_bitmap bitmap;
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t_snd snd;
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uint32 aim_m68k = 0;
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uint32 count_m68k = 0;
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uint32 dma_m68k = 0;
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uint32 aim_z80 = 0;
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uint32 count_z80 = 0;
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uint16 misc68Kcycles = 488;
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uint16 miscZ80cycles = 228;
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uint16 lines_per_frame = 262;
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double CPU_Clock = (double)CLOCK_NTSC;
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void *myFM = NULL;
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static int sound_tbl[312];
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static int sound_inc[312];
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uint8 alttiming = 0;
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void m68k_run (int cyc)
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{
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/* cycles remaining to run for the line */
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int cyc_do = cyc - count_m68k;
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/* 68k is not frozen */
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if (cyc_do > 0)
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{
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/* interrupt handling */
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if (vint_pending && (reg[1] & 0x20)) m68k_set_irq(6);
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else if (hint_pending && (reg[0] & 0x10)) m68k_set_irq(4);
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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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}
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}
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void z80_run (int cyc)
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{
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int cyc_do = cyc - count_z80;
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if (cyc_do > 0) count_z80 += z80_execute(cyc_do);
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}
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void m68k_freeze(int cycles)
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{
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extern int m68ki_remaining_cycles;
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int extra_cycles = cycles - m68k_cycles_remaining();
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if (extra_cycles > 0)
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{
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/* end of 68k execution */
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m68ki_remaining_cycles = 0;
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/* extra cycles to be burned at next execution */
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count_m68k += extra_cycles;
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}
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else m68ki_remaining_cycles -= cycles; /* we burn some 68k cycles */
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}
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extern uint8 hq_fm;
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int audio_init (int rate)
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{
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int i;
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int vclk = (int)(CPU_Clock / 7.0); /* 68000 and YM2612 clock */
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int zclk = (int)(CPU_Clock / 15.0); /* Z80 and SN76489 clock */
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/* Clear the sound data context */
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memset (&snd, 0, sizeof (snd));
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/* Make sure the requested sample rate is valid */
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if (!rate || ((rate < 8000) | (rate > 48000))) return (0);
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/* Calculate the sound buffer size */
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snd.buffer_size = (rate / vdp_rate);
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snd.sample_rate = rate;
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/* Allocate sound buffers */
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if (FM_GENS)
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{
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snd.fm.gens_buffer[0] = realloc (snd.fm.gens_buffer[0], snd.buffer_size * sizeof (int));
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snd.fm.gens_buffer[1] = realloc (snd.fm.gens_buffer[1], snd.buffer_size * sizeof (int));
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if (!snd.fm.gens_buffer[0] || !snd.fm.gens_buffer[1]) return (-1);
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memset (snd.fm.gens_buffer[0], 0, SND_SIZE*2);
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memset (snd.fm.gens_buffer[1], 0, SND_SIZE*2);
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}
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else
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{
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snd.fm.buffer[0] = realloc (snd.fm.buffer[0], snd.buffer_size * sizeof (int16));
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snd.fm.buffer[1] = realloc (snd.fm.buffer[1], snd.buffer_size * sizeof (int16));
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if (!snd.fm.buffer[0] || !snd.fm.buffer[1]) return (-1);
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memset (snd.fm.buffer[0], 0, SND_SIZE);
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memset (snd.fm.buffer[1], 0, SND_SIZE);
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}
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snd.psg.buffer = realloc (snd.psg.buffer, snd.buffer_size * sizeof (int16));
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if (!snd.psg.buffer) return (-1);
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memset (snd.psg.buffer, 0, SND_SIZE);
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/* Set audio enable flag */
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snd.enabled = 1;
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/* Initialize sound chip emulation */
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if (PSG_MAME) SN76496_sh_start(zclk, 0, rate);
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else
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{
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SN76489_Init(0, zclk, rate);
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SN76489_Config(0, MUTE_ALLON, VOL_FULL, FB_SEGAVDP, SRW_SEGAVDP, 0);
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}
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if (FM_GENS) YM2612_Init(vclk, rate, hq_fm);
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else if (!myFM) myFM = YM2612Init (0, 0, vclk, rate, 0, 0);
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/* Make sound table */
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for (i = 0; i < lines_per_frame; i++)
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{
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float p = (snd.buffer_size * i) / lines_per_frame;
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float q = (snd.buffer_size * (i+1)) / lines_per_frame;
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sound_tbl[i] = p;
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sound_inc[i] = ((q - p) * 1000000) / snd.sample_rate;
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}
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return (0);
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}
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void system_init (void)
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{
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/* PAL or NTSC timings */
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vdp_rate = (vdp_pal) ? 50 : 60;
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lines_per_frame = (vdp_pal) ? 313 : 262;
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CPU_Clock = (vdp_pal) ? (double)CLOCK_PAL : (double)CLOCK_NTSC;
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miscZ80cycles = (vdp_pal) ? 227 : 228;
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misc68Kcycles = (vdp_pal) ? 487 : 488;
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gen_init ();
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vdp_init ();
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render_init ();
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sound_init();
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}
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void system_reset (void)
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{
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aim_m68k = 0;
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count_m68k = 0;
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dma_m68k = 0;
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aim_z80 = 0;
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count_z80 = 0;
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gen_reset ();
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io_reset();
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vdp_reset ();
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render_reset ();
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if (snd.enabled)
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{
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fm_reset();
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if (FM_GENS)
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{
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memset (snd.fm.gens_buffer[0], 0, SND_SIZE*2);
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memset (snd.fm.gens_buffer[1], 0, SND_SIZE*2);
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}
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else
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{
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memset (snd.fm.buffer[0], 0, SND_SIZE);
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memset (snd.fm.buffer[1], 0, SND_SIZE);
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}
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if (!PSG_MAME) SN76489_Reset(0);
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memset (snd.psg.buffer, 0, SND_SIZE);
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}
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}
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void system_shutdown (void)
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{
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gen_shutdown ();
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vdp_shutdown ();
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render_shutdown ();
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}
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int system_frame (int do_skip)
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{
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/* update total cycles count */
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dma_m68k += count_m68k;
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/* reset line cycles counts */
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aim_m68k = 0;
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count_m68k = 0;
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aim_z80 = 0;
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count_z80 = 0;
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lastbusreqcnt = -1000;
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if (!gen_running) return 0;
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/* Clear V-Blank flag */
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status &= 0xFFF7;
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/* Toggle even/odd flag (IM2 only) */
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if (im2_flag) status ^= 0x0010;
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/* Reset HCounter */
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h_counter = reg[10];
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/* Point to start of sound buffer */
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snd.fm.lastStage = snd.fm.curStage = 0;
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snd.psg.lastStage = snd.psg.curStage = 0;
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/* Parse sprites for line 0 (done on line 261 or 312) */
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parse_satb (0x80);
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/* Line processing */
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for (v_counter = 0; v_counter < lines_per_frame; v_counter ++)
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{
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/* update cpu cycles goal for the line */
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aim_z80 += miscZ80cycles;
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aim_m68k += misc68Kcycles;
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/* 6-Buttons or Menacer update */
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input_update();
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/* If a Z80 interrupt is still pending after a scanline, cancel it */
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if (zirq)
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{
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zirq = 0;
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z80_set_irq_line(0, CLEAR_LINE);
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}
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/* H Int */
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if (v_counter <= frame_end)
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{
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if(--h_counter < 0)
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{
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h_counter = reg[10];
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hint_pending = 1;
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if (alttiming) m68k_run(aim_m68k - 456); /* fix Legend of Galahad */
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}
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}
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/* Render a line of the display if needed */
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if (do_skip == 0)
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{
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if (v_counter < frame_end) render_line(v_counter);
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if (v_counter < (frame_end-1)) parse_satb(0x81 + v_counter);
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}
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/* H retrace */
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status |= 0x0004; // HBlank = 1
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m68k_run(aim_m68k - 404);
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status &= 0xFFFB; // HBlank = 0
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if (v_counter == frame_end)
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{
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/* V Retrace */
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status |= 0x0008; // VBlank = 1
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m68k_run(aim_m68k - 360);
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if (zreset == 1 && zbusreq == 0) z80_run(aim_z80 - 168);
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else count_z80 = aim_z80 - 168;
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/* V Int */
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vint_pending = 1;
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status |= 0x0080;
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/* Z Int */
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if (zreset == 1 && zbusreq == 0)
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{
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zirq = 1;
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z80_set_irq_line(0, ASSERT_LINE);
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}
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}
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/* Process end of line */
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m68k_run(aim_m68k);
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if (zreset == 1 && zbusreq == 0) z80_run(aim_z80);
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else count_z80 = aim_z80;
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/* Update sound buffers and timers */
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fm_update_timers (sound_inc[v_counter]);
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snd.fm.curStage = sound_tbl[v_counter];
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snd.psg.curStage = sound_tbl[v_counter];
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}
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if (snd.enabled) audio_update ();
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return gen_running;
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}
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#ifdef NGC
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/****************************************************************************
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* softdev - 09 Mar 2006
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*
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*
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* Nintendo Gamecube Specific Mixer from here on in ...
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****************************************************************************/
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extern unsigned char soundbuffer[16][3840];
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extern int mixbuffer;
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extern double psg_preamp;
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extern double fm_preamp;
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extern u8 boost;
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static int ll, rr;
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void audio_update (void)
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{
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int i;
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int l, r;
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int16 *tempBuffer[2];
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int16 *sb = (int16 *) soundbuffer[mixbuffer];
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/* get remaining samples */
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/* YM2612 */
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if (FM_GENS)
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{
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int *fmBuffer[2];
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fmBuffer[0] = snd.fm.gens_buffer[0] + snd.fm.lastStage;
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fmBuffer[1] = snd.fm.gens_buffer[1] + snd.fm.lastStage;
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YM2612_Update(fmBuffer, snd.buffer_size - snd.fm.lastStage);
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}
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else
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{
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tempBuffer[0] = snd.fm.buffer[0] + snd.fm.lastStage;
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tempBuffer[1] = snd.fm.buffer[1] + snd.fm.lastStage;
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YM2612UpdateOne (myFM, tempBuffer, snd.buffer_size - snd.fm.lastStage);
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}
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/* PSG */
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tempBuffer[0] = snd.psg.buffer + snd.psg.lastStage;
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if (PSG_MAME) SN76496Update (0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
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else SN76489_Update(0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
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/* mix samples */
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for (i = 0; i < snd.buffer_size; i ++)
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{
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/* PSG */
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l = r = (int) ((double)snd.psg.buffer[i] * psg_preamp);
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if (FM_GENS)
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{
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l += (int) ((double)snd.fm.gens_buffer[0][i] * fm_preamp);
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r += (int) ((double)snd.fm.gens_buffer[1][i] * fm_preamp);
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snd.fm.gens_buffer[0][i] = 0;
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snd.fm.gens_buffer[1][i] = 0;
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}
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else
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{
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l += (int) ((double)snd.fm.buffer[0][i] * fm_preamp);
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r += (int) ((double)snd.fm.buffer[1][i] * fm_preamp);
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}
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/* single-pole low-pass filter (6 dB/octave) */
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ll = (ll + l) >> 1;
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rr = (rr + r) >> 1;
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l = ll * boost;
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r = rr * boost;
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/* clipping */
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if (l > 32767) l = 32767;
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else if (l < -32768) l = -32768;
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if (r > 32767) r = 32767;
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else if (r < -32768) r = -32768;
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*sb++ = l;
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*sb++ = r;
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}
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mixbuffer++;
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mixbuffer &= 0xf;
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}
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#else
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void audio_update (void)
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{
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int i;
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int16 acc;
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int16 *tempBuffer[2];
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if (FM_GENS)
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{
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int *fmBuffer[2];
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fmBuffer[0] = snd.fm.gens_buffer[0] + snd.fm.lastStage;
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fmBuffer[1] = snd.fm.gens_buffer[1] + snd.fm.lastStage;
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YM2612_Update(fmBuffer, snd.buffer_size - snd.fm.lastStage);
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}
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else
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{
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tempBuffer[0] = snd.fm.buffer[0] + snd.fm.lastStage;
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tempBuffer[1] = snd.fm.buffer[1] + snd.fm.lastStage;
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YM2612UpdateOne (myFM, tempBuffer, snd.buffer_size - snd.fm.lastStage);
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}
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tempBuffer[0] = snd.psg.buffer + snd.psg.lastStage;
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if (PSG_MAME) SN76496Update (0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
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else SN76489_Update(0, tempBuffer[0], snd.buffer_size - snd.psg.lastStage);
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for (i = 0; i < snd.buffer_size; i += 1)
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{
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int16 psg = snd.psg.buffer[i] / 2;
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acc = 0;
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acc += FM_GENS ? snd.fm.gens_buffer[0][i] : snd.fm.buffer[0][i];
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acc += psg;
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snd.buffer[0][i] = acc;
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acc = 0;
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acc += FM_GENS ? snd.fm.gens_buffer[1][i] : snd.fm.buffer[1][i];
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acc += psg;
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snd.buffer[1][i] = acc;
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if (FM_GENS)
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{
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snd.fm.gens_buffer[0][i] = 0;
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snd.fm.gens_buffer[1][i] = 0;
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}
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}
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}
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#endif
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