150 lines
4.0 KiB
C
150 lines
4.0 KiB
C
/* Copyright holders: Sarah Walker
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see COPYING for more details
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*/
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/*PC200 video emulation.
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CGA with some NMI stuff. But we don't need that as it's only used for TV and
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LCD displays, and we're emulating a CRT*/
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#include <stdlib.h>
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#include "ibm.h"
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#include "device.h"
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#include "io.h"
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#include "mem.h"
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#include "timer.h"
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#include "video.h"
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#include "vid_cga.h"
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#include "vid_pc200.h"
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typedef struct pc200_t
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{
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mem_mapping_t mapping;
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cga_t cga;
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uint8_t reg_3dd, reg_3de, reg_3df;
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} pc200_t;
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static uint8_t crtcmask[32] =
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{
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0xff, 0xff, 0xff, 0xff, 0x7f, 0x1f, 0x7f, 0x7f, 0xf3, 0x1f, 0x7f, 0x1f, 0x3f, 0xff, 0x3f, 0xff,
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0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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void pc200_out(uint16_t addr, uint8_t val, void *p)
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{
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pc200_t *pc200 = (pc200_t *)p;
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cga_t *cga = &pc200->cga;
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uint8_t old;
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switch (addr)
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{
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case 0x3d5:
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if (!(pc200->reg_3de & 0x40) && cga->crtcreg <= 11)
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{
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if (pc200->reg_3de & 0x80)
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nmi = 1;
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pc200->reg_3dd = 0x20 | (cga->crtcreg & 0x1f);
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pc200->reg_3df = val;
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return;
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}
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old = cga->crtc[cga->crtcreg];
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cga->crtc[cga->crtcreg] = val & crtcmask[cga->crtcreg];
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if (old != val)
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{
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if (cga->crtcreg < 0xe || cga->crtcreg > 0x10)
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{
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fullchange = changeframecount;
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cga_recalctimings(cga);
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}
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}
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return;
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case 0x3d8:
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old = cga->cgamode;
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cga->cgamode = val;
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if ((cga->cgamode ^ old) & 3)
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cga_recalctimings(cga);
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pc200->reg_3dd |= 0x80;
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if (pc200->reg_3de & 0x80)
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nmi = 1;
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return;
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case 0x3de:
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pc200->reg_3de = val;
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pc200->reg_3dd = 0x1f;
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if (val & 0x80)
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pc200->reg_3dd |= 0x40;
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return;
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}
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cga_out(addr, val, cga);
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}
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uint8_t pc200_in(uint16_t addr, void *p)
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{
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pc200_t *pc200 = (pc200_t *)p;
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cga_t *cga = &pc200->cga;
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uint8_t temp;
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switch (addr)
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{
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case 0x3D8:
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return cga->cgamode;
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case 0x3DD:
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temp = pc200->reg_3dd;
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pc200->reg_3dd &= 0x1f;
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nmi = 0;
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return temp;
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case 0x3DE:
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return (pc200->reg_3de & 0xc7) | 0x10; /*External CGA*/
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case 0x3DF:
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return pc200->reg_3df;
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}
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return cga_in(addr, cga);
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}
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void *pc200_init()
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{
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pc200_t *pc200 = malloc(sizeof(pc200_t));
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cga_t *cga = &pc200->cga;
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memset(pc200, 0, sizeof(pc200_t));
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pc200->cga.vram = malloc(0x4000);
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cga_init(&pc200->cga);
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timer_add(cga_poll, &cga->vidtime, TIMER_ALWAYS_ENABLED, cga);
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mem_mapping_add(&pc200->mapping, 0xb8000, 0x08000, cga_read, NULL, NULL, cga_write, NULL, NULL, NULL, 0, cga);
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io_sethandler(0x03d0, 0x0010, pc200_in, NULL, NULL, pc200_out, NULL, NULL, pc200);
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overscan_x = overscan_y = 16;
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return pc200;
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}
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void pc200_close(void *p)
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{
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pc200_t *pc200 = (pc200_t *)p;
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free(pc200->cga.vram);
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free(pc200);
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}
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void pc200_speed_changed(void *p)
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{
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pc200_t *pc200 = (pc200_t *)p;
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cga_recalctimings(&pc200->cga);
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}
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device_t pc200_device =
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{
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"Amstrad PC200 (video)",
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0,
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pc200_init,
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pc200_close,
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NULL,
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pc200_speed_changed,
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NULL,
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NULL
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};
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