93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
/* Copyright holders: Sarah Walker
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see COPYING for more details
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*/
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/*This is the chipset used in the AMI 286 clone model*/
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <wchar.h>
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#include "../ibm.h"
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#include "../io.h"
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#include "machine.h"
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static uint8_t neat_regs[256];
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static int neat_index;
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static int neat_emspage[4];
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static void neat_write(uint16_t port, uint8_t val, void *priv)
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{
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switch (port)
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{
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case 0x22:
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neat_index = val;
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break;
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case 0x23:
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neat_regs[neat_index] = val;
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switch (neat_index)
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{
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case 0x6E: /*EMS page extension*/
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neat_emspage[3] = (neat_emspage[3] & 0x7F) | (( val & 3) << 7);
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neat_emspage[2] = (neat_emspage[2] & 0x7F) | (((val >> 2) & 3) << 7);
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neat_emspage[1] = (neat_emspage[1] & 0x7F) | (((val >> 4) & 3) << 7);
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neat_emspage[0] = (neat_emspage[0] & 0x7F) | (((val >> 6) & 3) << 7);
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break;
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}
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break;
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case 0x0208: case 0x0209: case 0x4208: case 0x4209:
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case 0x8208: case 0x8209: case 0xC208: case 0xC209:
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neat_emspage[port >> 14] = (neat_emspage[port >> 14] & 0x180) | (val & 0x7F);
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break;
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}
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}
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static uint8_t neat_read(uint16_t port, void *priv)
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{
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switch (port)
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{
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case 0x22:
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return neat_index;
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case 0x23:
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return neat_regs[neat_index];
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}
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return 0xff;
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}
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#if NOT_USED
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static void neat_writeems(uint32_t addr, uint8_t val)
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{
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ram[(neat_emspage[(addr >> 14) & 3] << 14) + (addr & 0x3FFF)] = val;
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}
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static uint8_t neat_readems(uint32_t addr)
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{
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return ram[(neat_emspage[(addr >> 14) & 3] << 14) + (addr & 0x3FFF)];
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}
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#endif
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static void neat_init(void)
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{
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io_sethandler(0x0022, 0x0002, neat_read, NULL, NULL, neat_write, NULL, NULL, NULL);
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io_sethandler(0x0208, 0x0002, neat_read, NULL, NULL, neat_write, NULL, NULL, NULL);
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io_sethandler(0x4208, 0x0002, neat_read, NULL, NULL, neat_write, NULL, NULL, NULL);
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io_sethandler(0x8208, 0x0002, neat_read, NULL, NULL, neat_write, NULL, NULL, NULL);
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io_sethandler(0xc208, 0x0002, neat_read, NULL, NULL, neat_write, NULL, NULL, NULL);
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}
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void
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machine_at_neat_init(machine_t *model)
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{
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machine_at_init(model);
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neat_init();
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}
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