mirror of https://github.com/hsoft/collapseos.git
88 lines
1.6 KiB
C
88 lines
1.6 KiB
C
/* Common code between shell, zasm and runbin.
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They all run on the same kind of virtual machine: A z80 CPU, 64K of RAM/ROM.
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*/
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#include <string.h>
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#include "emul.h"
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static Machine m;
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static uint8_t io_read(int unused, uint16_t addr)
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{
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addr &= 0xff;
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IORD fn = m.iord[addr];
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if (fn != NULL) {
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return fn();
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} else {
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fprintf(stderr, "Out of bounds I/O read: %d\n", addr);
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return 0;
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}
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}
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static void io_write(int unused, uint16_t addr, uint8_t val)
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{
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addr &= 0xff;
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IOWR fn = m.iowr[addr];
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if (fn != NULL) {
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fn(val);
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} else {
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fprintf(stderr, "Out of bounds I/O write: %d / %d (0x%x)\n", addr, val, val);
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}
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}
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static uint8_t mem_read(int unused, uint16_t addr)
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{
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return m.mem[addr];
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}
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static void mem_write(int unused, uint16_t addr, uint8_t val)
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{
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if (addr < m.ramstart) {
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fprintf(stderr, "Writing to ROM (%d)!\n", addr);
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}
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m.mem[addr] = val;
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}
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Machine* emul_init()
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{
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memset(m.mem, 0, 0x10000);
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m.ramstart = 0;
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m.minsp = 0xffff;
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for (int i=0; i<0x100; i++) {
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m.iord[i] = NULL;
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m.iowr[i] = NULL;
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}
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Z80RESET(&m.cpu);
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m.cpu.memRead = mem_read;
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m.cpu.memWrite = mem_write;
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m.cpu.ioRead = io_read;
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m.cpu.ioWrite = io_write;
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return &m;
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}
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bool emul_step()
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{
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if (!m.cpu.halted) {
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Z80Execute(&m.cpu);
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ushort newsp = m.cpu.R1.wr.SP;
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if (newsp != 0 && newsp < m.minsp) {
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m.minsp = newsp;
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}
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return true;
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} else {
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return false;
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}
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}
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void emul_loop()
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{
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while (emul_step());
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}
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void emul_printdebug()
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{
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fprintf(stderr, "Min SP: %04x\n", m.minsp);
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}
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