68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
#include "ibm.h"
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#include "io.h"
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#include "mem.h"
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#include "dells200.h"
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static struct
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{
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uint8_t regs[3];
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} dells200;
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static uint8_t dells200_in(uint16_t addr, void *p)
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{
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uint8_t ret = 0xff;
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switch (addr)
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{
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case 0xa4:
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ret = dells200.regs[0];
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break;
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case 0xa5:
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ret = dells200.regs[1];
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break;
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case 0xab:
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ret = dells200.regs[2];
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break;
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}
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// pclog("dells200_in: addr=%04x ret=%02x %04x(%08x):%08x\n", addr, ret, CS,cs,cpu_state.pc);
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return ret;
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}
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static void dells200_out(uint16_t addr, uint8_t val, void *p)
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{
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// pclog("dells200_out: addr=%04x val=%02x %04x(%08x):%08x\n", addr, val, CS,cs,cpu_state.pc);
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switch (addr)
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{
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case 0xa4:
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dells200.regs[0] = val;
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mem_a20_alt = val & 0x40;
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mem_a20_recalc();
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break;
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case 0xa5:
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dells200.regs[1] = val;
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if (val & 1)
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mem_mapping_set_addr(&ram_low_mapping, 0, 0x40000);
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else
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mem_mapping_set_addr(&ram_low_mapping, 0, 0xa0000);
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if (val & 1)
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mem_mapping_disable(&ram_high_mapping);
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else
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mem_mapping_enable(&ram_high_mapping);
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break;
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case 0xab:
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dells200.regs[2] = val;
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break;
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}
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}
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void dells200_chipset_init()
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{
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memset(&dells200, 0, sizeof(dells200));
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io_sethandler(0x00a4, 0x0002, dells200_in,NULL,NULL, dells200_out,NULL,NULL, NULL);
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io_sethandler(0x00ab, 0x0001, dells200_in,NULL,NULL, dells200_out,NULL,NULL, NULL);
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}
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