mirror of
https://github.com/RaySollium99/picodrive.git
synced 2025-09-06 07:38:05 -04:00
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.
104 lines
2.6 KiB
C
104 lines
2.6 KiB
C
/*
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* PicoDrive
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* (C) notaz, 2008
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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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// x: 0x03c - 0x19d
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// y: 0x1fc - 0x2f7
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// 0x2f8 - 0x3f3
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picohw_state PicoPicohw;
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static int prev_line_cnt_irq3 = 0, prev_line_cnt_irq5 = 0;
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static int fifo_bytes_line = (16000<<16)/60/262/2;
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static const int guessed_rates[] = { 8000, 14000, 12000, 14000, 16000, 18000, 16000, 16000 }; // ?
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#define PICOHW_FIFO_IRQ_THRESHOLD 12
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PICO_INTERNAL void PicoReratePico(void)
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{
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int rate = guessed_rates[PicoPicohw.r12 & 7];
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if (Pico.m.pal)
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fifo_bytes_line = (rate<<16)/50/312/2;
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else fifo_bytes_line = (rate<<16)/60/262/2;
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PicoPicoPCMRerate(rate);
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}
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static void PicoLinePico(void)
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{
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PicoPicohw.line_counter++;
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#if 1
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if ((PicoPicohw.r12 & 0x4003) && PicoPicohw.line_counter - prev_line_cnt_irq3 > 200) {
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prev_line_cnt_irq3 = PicoPicohw.line_counter;
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// just a guess/hack, allows 101 Dalmantians to boot
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elprintf(EL_PICOHW, "irq3");
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SekInterrupt(3);
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return;
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}
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#endif
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if (PicoPicohw.fifo_bytes > 0)
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{
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PicoPicohw.fifo_line_bytes += fifo_bytes_line;
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if (PicoPicohw.fifo_line_bytes >= (1<<16)) {
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PicoPicohw.fifo_bytes -= PicoPicohw.fifo_line_bytes >> 16;
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PicoPicohw.fifo_line_bytes &= 0xffff;
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if (PicoPicohw.fifo_bytes < 0)
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PicoPicohw.fifo_bytes = 0;
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}
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}
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else
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PicoPicohw.fifo_line_bytes = 0;
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#if 1
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if (PicoPicohw.fifo_bytes_prev >= PICOHW_FIFO_IRQ_THRESHOLD &&
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PicoPicohw.fifo_bytes < PICOHW_FIFO_IRQ_THRESHOLD) {
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prev_line_cnt_irq3 = PicoPicohw.line_counter; // ?
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elprintf(EL_PICOHW, "irq3, fb=%i", PicoPicohw.fifo_bytes);
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SekInterrupt(3);
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}
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PicoPicohw.fifo_bytes_prev = PicoPicohw.fifo_bytes;
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#endif
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#if 0
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if (PicoPicohw.line_counter - prev_line_cnt_irq5 > 512) {
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prev_line_cnt_irq5 = PicoPicohw.line_counter;
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elprintf(EL_PICOHW, "irq5");
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SekInterrupt(5);
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}
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#endif
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}
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static void PicoResetPico(void)
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{
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PicoPicoPCMReset();
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PicoPicohw.xpcm_ptr = PicoPicohw.xpcm_buffer;
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}
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PICO_INTERNAL void PicoInitPico(void)
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{
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elprintf(EL_STATUS, "Pico startup");
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PicoLineHook = PicoLinePico;
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PicoResetHook = PicoResetPico;
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PicoAHW = PAHW_PICO;
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memset(&PicoPicohw, 0, sizeof(PicoPicohw));
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PicoPicohw.pen_pos[0] = 0x03c + 320/2;
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PicoPicohw.pen_pos[1] = 0x200 + 240/2;
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prev_line_cnt_irq3 = prev_line_cnt_irq5 = 0;
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// map version register
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PicoDetectRegion();
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switch (Pico.m.hardware >> 6) {
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case 0: PicoPicohw.r1 = 0x00; break;
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case 1: PicoPicohw.r1 = 0x00; break;
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case 2: PicoPicohw.r1 = 0x40; break;
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case 3: PicoPicohw.r1 = 0x20; break;
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}
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}
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