40 lines
816 B
C
40 lines
816 B
C
/*INTEL 82355 MCR emulation
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This chip was used as part of many 386 chipsets
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It controls memory addressing and shadowing*/
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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 "86box.h"
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#include "ibm.h"
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int nextreg6;
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uint8_t mcr22;
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int mcrlock,mcrfirst;
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void resetmcr(void)
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{
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mcrlock=0;
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mcrfirst=1;
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shadowbios=0;
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}
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void writemcr(uint16_t addr, uint8_t val)
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{
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printf("Write MCR %04X %02X %04X:%04X\n",addr,val,CS,cpu_state.pc);
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switch (addr)
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{
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case 0x22:
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if (val==6 && mcr22==6) nextreg6=1;
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else nextreg6=0;
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break;
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case 0x23:
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if (nextreg6) shadowbios=!val;
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break;
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}
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mcr22=val;
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}
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