105 lines
2.6 KiB
C
105 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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