mirror of
https://github.com/RaySollium99/picodrive.git
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cff531af94
- PicoDrive was originally released by fDave with simple
"free for non-commercial use / For commercial use, separate licencing
terms must be obtained" license and I kept it in my releases.
- in 2011, fDave re-released his code (same that I used as base
many years ago) dual licensed with GPLv2 and MAME licenses:
https://code.google.com/p/cyclone68000/
Based on the above I now proclaim that the whole source code is licensed
under the MAME license as more elaborate form of "for non-commercial use".
If that raises any doubt, I announce that all my modifications (which
is the vast majority of code by now) is licensed under the MAME license,
as it reads in COPYING file in this commit.
This does not affect ym2612.c/sn76496.c that were MAME licensed already
from the beginning.
137 lines
4.2 KiB
C
137 lines
4.2 KiB
C
/*
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* Emulation routines for the RF5C164 PCM chip
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* (C) notaz, 2007
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*
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* This work is licensed under the terms of MAME license.
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* See COPYING file in the top-level directory.
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*/
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#include "../pico_int.h"
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#include "pcm.h"
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static unsigned int g_rate = 0; // 18.14 fixed point
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PICO_INTERNAL_ASM void pcm_write(unsigned int a, unsigned int d)
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{
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//printf("pcm_write(%i, %02x)\n", a, d);
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if (a < 7)
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{
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Pico_mcd->pcm.ch[Pico_mcd->pcm.cur_ch].regs[a] = d;
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}
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else if (a == 7) // control register
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{
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if (d & 0x40) Pico_mcd->pcm.cur_ch = d & 7;
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else Pico_mcd->pcm.bank = d & 0xf;
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Pico_mcd->pcm.control = d;
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// dprintf("pcm control=%02x", Pico_mcd->pcm.control);
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}
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else if (a == 8) // sound on/off
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{
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if (!(Pico_mcd->pcm.enabled & 0x01)) Pico_mcd->pcm.ch[0].addr =
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Pico_mcd->pcm.ch[0].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x02)) Pico_mcd->pcm.ch[1].addr =
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Pico_mcd->pcm.ch[1].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x04)) Pico_mcd->pcm.ch[2].addr =
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Pico_mcd->pcm.ch[2].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x08)) Pico_mcd->pcm.ch[3].addr =
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Pico_mcd->pcm.ch[3].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x10)) Pico_mcd->pcm.ch[4].addr =
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Pico_mcd->pcm.ch[4].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x20)) Pico_mcd->pcm.ch[5].addr =
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Pico_mcd->pcm.ch[5].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x40)) Pico_mcd->pcm.ch[6].addr =
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Pico_mcd->pcm.ch[6].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x80)) Pico_mcd->pcm.ch[7].addr =
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Pico_mcd->pcm.ch[7].regs[6] << (PCM_STEP_SHIFT + 8);
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// printf("addr %x %x %x %x %x %x %x %x\n", Pico_mcd->pcm.ch[0].addr, Pico_mcd->pcm.ch[1].addr
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// , Pico_mcd->pcm.ch[2].addr, Pico_mcd->pcm.ch[3].addr, Pico_mcd->pcm.ch[4].addr, Pico_mcd->pcm.ch[5].addr
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// , Pico_mcd->pcm.ch[6].addr, Pico_mcd->pcm.ch[7].addr);
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Pico_mcd->pcm.enabled = ~d;
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//printf("enabled=%02x\n", Pico_mcd->pcm.enabled);
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}
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}
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PICO_INTERNAL void pcm_set_rate(int rate)
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{
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float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
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step *= 256*256/4;
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g_rate = (unsigned int) step;
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if (step - (float) g_rate >= 0.5) g_rate++;
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elprintf(EL_STATUS, "g_rate: %f %08x\n", (double)step, g_rate);
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}
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PICO_INTERNAL void pcm_update(int *buffer, int length, int stereo)
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{
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struct pcm_chan *ch;
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unsigned int step, addr;
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int mul_l, mul_r, smp;
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int i, j, k;
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int *out;
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// PCM disabled or all channels off (to be checked by caller)
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//if (!(Pico_mcd->pcm.control & 0x80) || !Pico_mcd->pcm.enabled) return;
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//printf("-- upd %i\n", length);
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for (i = 0; i < 8; i++)
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{
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if (!(Pico_mcd->pcm.enabled & (1 << i))) continue; // channel disabled
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out = buffer;
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ch = &Pico_mcd->pcm.ch[i];
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addr = ch->addr; // >> PCM_STEP_SHIFT;
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mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
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mul_r = ((int)ch->regs[0] * (ch->regs[1] >> 4)) >> (5+1);
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step = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
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// fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
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// *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
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if (!stereo && mul_l < mul_r) mul_l = mul_r;
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for (j = 0; j < length; j++)
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{
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// printf("addr=%08x\n", addr);
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smp = Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT];
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// test for loop signal
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if (smp == 0xff)
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{
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addr = *(unsigned short *)&ch->regs[4]; // loop_addr
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smp = Pico_mcd->pcm_ram[addr];
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addr <<= PCM_STEP_SHIFT;
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if (smp == 0xff) break;
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}
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if (smp & 0x80) smp = -(smp & 0x7f);
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*out++ += smp * mul_l; // max 128 * 119 = 15232
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if(stereo)
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*out++ += smp * mul_r;
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// update address register
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k = (addr >> PCM_STEP_SHIFT) + 1;
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addr = (addr + step) & 0x7FFFFFF;
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for(; k < (addr >> PCM_STEP_SHIFT); k++)
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{
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if (Pico_mcd->pcm_ram[k] == 0xff)
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{
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addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
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break;
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}
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}
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}
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if (Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT] == 0xff)
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addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
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ch->addr = addr;
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}
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}
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