76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
#include "ibm.h"
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#include "io.h"
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#include "mem.h"
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#include "sl82c460.h"
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static struct
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{
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int reg_idx;
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uint8_t regs[256];
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} sl82c460;
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static void sl82c460_shadow_set(uint32_t base, uint32_t size, int state)
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{
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switch (state)
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{
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case 0:
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mem_set_mem_state(base, size, MEM_READ_EXTERNAL | MEM_WRITE_EXTERNAL);
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break;
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case 1:
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mem_set_mem_state(base, size, MEM_READ_EXTERNAL | MEM_WRITE_INTERNAL);
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break;
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case 2:
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mem_set_mem_state(base, size, MEM_READ_INTERNAL | MEM_WRITE_EXTERNAL);
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break;
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case 3:
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mem_set_mem_state(base, size, MEM_READ_INTERNAL | MEM_WRITE_INTERNAL);
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break;
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}
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}
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static void sl82c460_shadow_recalc()
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{
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sl82c460_shadow_set(0xc0000, 0x4000, sl82c460.regs[0x18] & 3);
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sl82c460_shadow_set(0xc4000, 0x4000, (sl82c460.regs[0x18] >> 2) & 3);
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sl82c460_shadow_set(0xc8000, 0x4000, (sl82c460.regs[0x18] >> 4) & 3);
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sl82c460_shadow_set(0xcc000, 0x4000, (sl82c460.regs[0x18] >> 6) & 3);
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sl82c460_shadow_set(0xd0000, 0x4000, sl82c460.regs[0x19] & 3);
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sl82c460_shadow_set(0xd4000, 0x4000, (sl82c460.regs[0x19] >> 2) & 3);
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sl82c460_shadow_set(0xd8000, 0x4000, (sl82c460.regs[0x19] >> 4) & 3);
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sl82c460_shadow_set(0xdc000, 0x4000, (sl82c460.regs[0x19] >> 6) & 3);
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sl82c460_shadow_set(0xe0000, 0x10000, (sl82c460.regs[0x1b] >> 4) & 3);
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sl82c460_shadow_set(0xf0000, 0x10000, (sl82c460.regs[0x1b] >> 2) & 3);
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}
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static void sl82c460_write(uint16_t addr, uint8_t val, void *p)
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{
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if (!(addr & 1))
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sl82c460.reg_idx = val;
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else
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{
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// pclog("SL82C460 write %02x %02x\n", sl82c460.reg_idx, val);
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sl82c460.regs[sl82c460.reg_idx] = val;
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switch (sl82c460.reg_idx)
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{
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case 0x18: case 0x19: case 0x1b:
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sl82c460_shadow_recalc();
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break;
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}
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}
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}
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static uint8_t sl82c460_read(uint16_t addr, void *p)
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{
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if (!(addr & 1))
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return sl82c460.reg_idx;
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return sl82c460.regs[sl82c460.reg_idx];
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}
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void sl82c460_init()
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{
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memset(&sl82c460, 0, sizeof(sl82c460));
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io_sethandler(0x00a8, 0x0002, sl82c460_read, NULL, NULL, sl82c460_write, NULL, NULL, NULL);
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}
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