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Partially implement Dell System 200 chipset. Fixes POST errors and HIMEM.SYS.

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This commit is contained in:
SarahW 2017-05-11 21:18:34 +01:00
commit a54e6575d3
8 changed files with 83 additions and 6 deletions
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68
src/dells200.c Normal file
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#include "ibm.h"
#include "io.h"
#include "mem.h"
#include "dells200.h"
static struct
{
uint8_t regs[3];
} dells200;
static uint8_t dells200_in(uint16_t addr, void *p)
{
uint8_t ret = 0xff;
switch (addr)
{
case 0xa4:
ret = dells200.regs[0];
break;
case 0xa5:
ret = dells200.regs[1];
break;
case 0xab:
ret = dells200.regs[2];
break;
}
// pclog("dells200_in: addr=%04x ret=%02x %04x(%08x):%08x\n", addr, ret, CS,cs,cpu_state.pc);
return ret;
}
static void dells200_out(uint16_t addr, uint8_t val, void *p)
{
// pclog("dells200_out: addr=%04x val=%02x %04x(%08x):%08x\n", addr, val, CS,cs,cpu_state.pc);
switch (addr)
{
case 0xa4:
dells200.regs[0] = val;
mem_a20_alt = val & 0x40;
mem_a20_recalc();
break;
case 0xa5:
dells200.regs[1] = val;
if (val & 1)
mem_mapping_set_addr(&ram_low_mapping, 0, 0x40000);
else
mem_mapping_set_addr(&ram_low_mapping, 0, 0xa0000);
if (val & 1)
mem_mapping_disable(&ram_high_mapping);
else
mem_mapping_enable(&ram_high_mapping);
break;
case 0xab:
dells200.regs[2] = val;
break;
}
}
void dells200_chipset_init()
{
memset(&dells200, 0, sizeof(dells200));
io_sethandler(0x00a4, 0x0002, dells200_in,NULL,NULL, dells200_out,NULL,NULL, NULL);
io_sethandler(0x00ab, 0x0001, dells200_in,NULL,NULL, dells200_out,NULL,NULL, NULL);
}