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yemu/src/ocpu/ocpu.c

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#include <yemu/ocpu.h>
struct OCPU ocpu;
struct OCPU_MEMORY ocpu_mem;
void ocpu_memory_init () {
for (int i = 0; i < MAX_MEMORY; i++){
ocpu_mem.memory[i] = 0;
}
}
byte ocpu_fetch_byte() {
byte data = ocpu_mem.memory[ocpu.PC];
ocpu.PC++;
return data;
}
word ocpu_fetch_word() {
word data = ocpu_mem.memory[ocpu.PC];
ocpu.PC++;
data |= (ocpu_mem.memory[ocpu.PC] << 8);
ocpu.PC++;
return data;
}
void ocpu_reset () {
ocpu.PC = 0x0000; // FIXME
ocpu.SP = 0x0000; //FIXME
ocpu.A = ocpu.B = ocpu.C = ocpu.D = ocpu.E = ocpu.F = 0;
ocpu.ZF = ocpu.NF = ocpu.CF = ocpu.OF = 0;
ocpu_memory_init(ocpu_mem);
}
void ocpu_dump_ocpu(struct OCPU ocpu) { // FIXME
printf("PC: %04X\n", ocpu.PC);
printf("SP: %04X\n", ocpu.SP);
printf("\n");
printf("AL: %04X BL: %04X\n", ocpu.AL, ocpu.BL);
printf("AH: %04X BH: %04X\n", ocpu.AH, ocpu.BH);
printf("A: %04X B: %04X\n", ocpu.A, ocpu.B);
printf("\n");
printf("CL: %04X DL: %04X\n", ocpu.CL, ocpu.DL);
printf("CH: %04X DH: %04X\n", ocpu.CH, ocpu.DH);
printf("C: %04X D: %04X\n", ocpu.C, ocpu.D);
printf("\n");
printf("EL: %04X FL: %04X\n", ocpu.EL, ocpu.FL);
printf("EH: %04X FH: %04X\n", ocpu.EH, ocpu.FH);
printf("E: %04X F: %04X\n", ocpu.E, ocpu.F);
printf("\n");
printf("Flags: ZF: %X, NF: %X, CF: %X, OF: %X\n", ocpu.ZF, ocpu.NF, ocpu.CF, ocpu.OF);
}
int match_register(byte reg) { // Function that returns register's value by taking register opcode
switch(reg) {
case REG_AL:
return ocpu.AL;
case REG_AH:
return ocpu.AH;
case REG_A:
return ocpu.A;
case REG_BL:
return ocpu.BL;
case REG_BH:
return ocpu.BH;
case REG_B:
return ocpu.B;
case REG_CL:
return ocpu.CL;
case REG_CH:
return ocpu.CH;
case REG_C:
return ocpu.C;
case REG_DL:
return ocpu.DL;
case REG_DH:
return ocpu.DH;
case REG_D:
return ocpu.D;
case REG_EL:
return ocpu.EL;
case REG_EH:
return ocpu.EH;
case REG_E:
return ocpu.E;
case REG_FL:
return ocpu.FL;
case REG_FH:
return ocpu.FH;
case REG_F:
return ocpu.F;
}
return 0xFF; // FIXME: add some error handling
}
void ocpu_execute() {
byte reg;
byte value;
word word_value;
while (1) {
byte instruction = ocpu_fetch_byte();
switch(instruction) {
case INS_MOV_IM:
reg = ocpu_fetch_byte();
switch(reg) {
case REG_AL:
value = ocpu_fetch_byte();
ocpu.A = (ocpu.A & 0xFF00) | (value & 0xFF);
ocpu.AL = ocpu.A & 0xFF;
break;
case REG_AH:
value = ocpu_fetch_byte();
ocpu.A = ((value & 0xFF) << 8) | (ocpu.A & 0xFF);
ocpu.AH = ocpu.A >> 8;
break;
case REG_A:
word_value = ocpu_fetch_word();
ocpu.A = word_value;
break;
case REG_BL:
value = ocpu_fetch_byte();
ocpu.B = (ocpu.B & 0xFF00) | (value & 0xFF);
ocpu.BL = ocpu.B & 0xFF;
break;
case REG_BH:
value = ocpu_fetch_byte();
ocpu.B = ((value & 0xFF) << 8) | (ocpu.B & 0xFF);
ocpu.BH = ocpu.B >> 8;
break;
case REG_B:
word_value = ocpu_fetch_word();
ocpu.B = word_value;
break;
case REG_CL:
value = ocpu_fetch_byte();
ocpu.C = (ocpu.C & 0xFF00) | (value & 0xFF);
ocpu.CL = ocpu.C & 0xFF;
break;
case REG_CH:
value = ocpu_fetch_byte();
ocpu.C = ((value & 0xFF) << 8) | (ocpu.C & 0xFF);
ocpu.CH = ocpu.C >> 8;
break;
case REG_C:
word_value = ocpu_fetch_word();
ocpu.C = word_value;
break;
case REG_DL:
value = ocpu_fetch_byte();
ocpu.D = (ocpu.D & 0xFF00) | (value & 0xFF);
ocpu.DL = ocpu.D & 0xFF;
break;
case REG_DH:
value = ocpu_fetch_byte();
ocpu.D = ((value & 0xFF) << 8) | (ocpu.D & 0xFF);
ocpu.DH = ocpu.D >> 8;
break;
case REG_D:
word_value = ocpu_fetch_word();
ocpu.D = word_value;
break;
case REG_EL:
value = ocpu_fetch_byte();
ocpu.E = (ocpu.E & 0xFF00) | (value & 0xFF);
ocpu.EL = ocpu.E & 0xFF;
break;
case REG_EH:
value = ocpu_fetch_byte();
ocpu.E = ((value & 0xFF) << 8) | (ocpu.E & 0xFF);
ocpu.EH = ocpu.E >> 8;
break;
case REG_E:
word_value = ocpu_fetch_word();
ocpu.E = word_value;
break;
case REG_FL:
value = ocpu_fetch_byte();
ocpu.F = (ocpu.F & 0xFF00) | (value & 0xFF);
ocpu.FL = ocpu.F & 0xFF;
break;
case REG_FH:
value = ocpu_fetch_byte();
ocpu.F = ((value & 0xFF) << 8) | (ocpu.F & 0xFF);
ocpu.FH = ocpu.F >> 8;
break;
case REG_F:
word_value = ocpu_fetch_word();
ocpu.F = word_value;
break;
default:
printf("Wrong register: %02X\n", reg);
return;
}
break;
case INS_MOV_REG:
reg = ocpu_fetch_byte();
switch(reg) {
case REG_AL:
value = match_register(ocpu_fetch_byte());
ocpu.A = (ocpu.A & 0xFF00) | (value & 0xFF);
ocpu.AL = ocpu.A & 0xFF;
break;
case REG_AH:
value = match_register(ocpu_fetch_byte());
ocpu.A = ((value & 0xFF) << 8) | (ocpu.A & 0xFF);
ocpu.AH = ocpu.A >> 8;
break;
case REG_A:
word_value = match_register(ocpu_fetch_byte());
ocpu.A = word_value;
break;
case REG_BL:
value = match_register(ocpu_fetch_byte());
ocpu.B = (ocpu.B & 0xFF00) | (value & 0xFF);
ocpu.BL = ocpu.B & 0xFF;
break;
case REG_BH:
value = match_register(ocpu_fetch_byte());
ocpu.B = ((value & 0xFF) << 8) | (ocpu.B & 0xFF);
ocpu.BH = ocpu.B >> 8;
break;
case REG_B:
word_value = match_register(ocpu_fetch_byte());
ocpu.B = word_value;
break;
case REG_CL:
value = match_register(ocpu_fetch_byte());
ocpu.C = (ocpu.C & 0xFF00) | (value & 0xFF);
ocpu.CL = ocpu.C & 0xFF;
break;
case REG_CH:
value = match_register(ocpu_fetch_byte());
ocpu.C = ((value & 0xFF) << 8) | (ocpu.C & 0xFF);
ocpu.CH = ocpu.C >> 8;
break;
case REG_C:
word_value = match_register(ocpu_fetch_byte());
ocpu.C = word_value;
break;
case REG_DL:
value = match_register(ocpu_fetch_byte());
ocpu.D = (ocpu.D & 0xFF00) | (value & 0xFF);
ocpu.DL = ocpu.D & 0xFF;
break;
case REG_DH:
value = match_register(ocpu_fetch_byte());
ocpu.D = ((value & 0xFF) << 8) | (ocpu.D & 0xFF);
ocpu.DH = ocpu.D >> 8;
break;
case REG_D:
word_value = match_register(ocpu_fetch_byte());
ocpu.D = word_value;
break;
case REG_EL:
value = match_register(ocpu_fetch_byte());
ocpu.E = (ocpu.E & 0xFF00) | (value & 0xFF);
ocpu.EL = ocpu.E & 0xFF;
break;
case REG_EH:
value = match_register(ocpu_fetch_byte());
ocpu.E = ((value & 0xFF) << 8) | (ocpu.E & 0xFF);
ocpu.EH = ocpu.E >> 8;
break;
case REG_E:
word_value = match_register(ocpu_fetch_byte());
ocpu.E = word_value;
break;
case REG_FL:
value = match_register(ocpu_fetch_byte());
ocpu.F = (ocpu.F & 0xFF00) | (value & 0xFF);
ocpu.FL = ocpu.F & 0xFF;
break;
case REG_FH:
value = match_register(ocpu_fetch_byte());
ocpu.F = ((value & 0xFF) << 8) | (ocpu.F & 0xFF);
ocpu.FH = ocpu.F >> 8;
break;
case REG_F:
word_value = match_register(ocpu_fetch_byte());
ocpu.F = word_value;
break;
default:
printf("Wrong register: %02X\n", reg);
return;
}
break;
case INS_ADD_IM:
reg = ocpu_fetch_byte();
switch(reg) {
case REG_AL:
value = ocpu_fetch_byte();
ocpu.A += (ocpu.A & 0xFF00) | (value & 0xFF);
ocpu.AL = ocpu.A & 0xFF;
break;
case REG_AH:
value = ocpu_fetch_byte();
ocpu.A += ((value & 0xFF) << 8) | (ocpu.A & 0xFF);
ocpu.AH = ocpu.A >> 8;
break;
case REG_A:
word_value = ocpu_fetch_word();
ocpu.A += word_value;
break;
case REG_BL:
value = ocpu_fetch_byte();
ocpu.B += (ocpu.B & 0xFF00) | (value & 0xFF);
ocpu.BL = ocpu.B & 0xFF;
break;
case REG_BH:
value = ocpu_fetch_byte();
ocpu.B += ((value & 0xFF) << 8) | (ocpu.B & 0xFF);
ocpu.BH = ocpu.B >> 8;
break;
case REG_B:
word_value = ocpu_fetch_word();
ocpu.B += word_value;
break;
case REG_CL:
value = ocpu_fetch_byte();
ocpu.C += (ocpu.C & 0xFF00) | (value & 0xFF);
ocpu.CL = ocpu.C & 0xFF;
break;
case REG_CH:
value = ocpu_fetch_byte();
ocpu.C += ((value & 0xFF) << 8) | (ocpu.C & 0xFF);
ocpu.CH = ocpu.C >> 8;
break;
case REG_C:
word_value = ocpu_fetch_word();
ocpu.C += word_value;
break;
case REG_DL:
value = ocpu_fetch_byte();
ocpu.D += (ocpu.D & 0xFF00) | (value & 0xFF);
ocpu.DL = ocpu.D & 0xFF;
break;
case REG_DH:
value = ocpu_fetch_byte();
ocpu.D += ((value & 0xFF) << 8) | (ocpu.D & 0xFF);
ocpu.DH = ocpu.D >> 8;
break;
case REG_D:
word_value = ocpu_fetch_word();
ocpu.D += word_value;
break;
case REG_EL:
value = ocpu_fetch_byte();
ocpu.E += (ocpu.E & 0xFF00) | (value & 0xFF);
ocpu.EL = ocpu.E & 0xFF;
break;
case REG_EH:
value = ocpu_fetch_byte();
ocpu.E += ((value & 0xFF) << 8) | (ocpu.E & 0xFF);
ocpu.EH = ocpu.E >> 8;
break;
case REG_E:
word_value = ocpu_fetch_word();
ocpu.E += word_value;
break;
case REG_FL:
value = ocpu_fetch_byte();
ocpu.F += (ocpu.F & 0xFF00) | (value & 0xFF);
ocpu.FL = ocpu.F & 0xFF;
break;
case REG_FH:
value = ocpu_fetch_byte();
ocpu.F += ((value & 0xFF) << 8) | (ocpu.F & 0xFF);
ocpu.FH = ocpu.F >> 8;
break;
case REG_F:
word_value = ocpu_fetch_word();
ocpu.F += word_value;
break;
default:
printf("Wrong register: %02X\n", reg);
return;
}
break;
case INS_ADD_REG:
reg = ocpu_fetch_byte();
switch(reg) {
case REG_AL:
value = match_register(ocpu_fetch_byte());
ocpu.A += (ocpu.A & 0xFF00) | (value & 0xFF);
ocpu.AL = ocpu.A & 0xFF;
break;
case REG_AH:
value = match_register(ocpu_fetch_byte());
ocpu.A += ((value & 0xFF) << 8) | (ocpu.A & 0xFF);
ocpu.AH = ocpu.A >> 8;
break;
case REG_A:
word_value = match_register(ocpu_fetch_byte());
ocpu.A += word_value;
break;
case REG_BL:
value = match_register(ocpu_fetch_byte());
ocpu.B += (ocpu.B & 0xFF00) | (value & 0xFF);
ocpu.BL = ocpu.B & 0xFF;
break;
case REG_BH:
value = match_register(ocpu_fetch_byte());
ocpu.B += ((value & 0xFF) << 8) | (ocpu.B & 0xFF);
ocpu.BH = ocpu.B >> 8;
break;
case REG_B:
word_value = match_register(ocpu_fetch_byte());
ocpu.B += word_value;
break;
case REG_CL:
value = match_register(ocpu_fetch_byte());
ocpu.C += (ocpu.C & 0xFF00) | (value & 0xFF);
ocpu.CL = ocpu.C & 0xFF;
break;
case REG_CH:
value = match_register(ocpu_fetch_byte());
ocpu.C += ((value & 0xFF) << 8) | (ocpu.C & 0xFF);
ocpu.CH = ocpu.C >> 8;
break;
case REG_C:
word_value = match_register(ocpu_fetch_byte());
ocpu.C += word_value;
break;
case REG_DL:
value = match_register(ocpu_fetch_byte());
ocpu.D += (ocpu.D & 0xFF00) | (value & 0xFF);
ocpu.DL = ocpu.D & 0xFF;
break;
case REG_DH:
value = match_register(ocpu_fetch_byte());
ocpu.D += ((value & 0xFF) << 8) | (ocpu.D & 0xFF);
ocpu.DH = ocpu.D >> 8;
break;
case REG_D:
word_value = match_register(ocpu_fetch_byte());
ocpu.D += word_value;
break;
case REG_EL:
value = match_register(ocpu_fetch_byte());
ocpu.E += (ocpu.E & 0xFF00) | (value & 0xFF);
ocpu.EL = ocpu.E & 0xFF;
break;
case REG_EH:
value = match_register(ocpu_fetch_byte());
ocpu.E += ((value & 0xFF) << 8) | (ocpu.E & 0xFF);
ocpu.EH = ocpu.E >> 8;
break;
case REG_E:
word_value = match_register(ocpu_fetch_byte());
ocpu.E += word_value;
break;
case REG_FL:
value = match_register(ocpu_fetch_byte());
ocpu.F += (ocpu.F & 0xFF00) | (value & 0xFF);
ocpu.FL = ocpu.F & 0xFF;
break;
case REG_FH:
value = match_register(ocpu_fetch_byte());
ocpu.F += ((value & 0xFF) << 8) | (ocpu.F & 0xFF);
ocpu.FH = ocpu.F >> 8;
break;
case REG_F:
word_value = match_register(ocpu_fetch_byte());
ocpu.F += word_value;
break;
default:
printf("Wrong register: %02X\n", reg);
return;
}
break;
case INS_INC:
reg = ocpu_fetch_byte();
switch(reg) {
case REG_AL:
ocpu.A++;
ocpu.AL = ocpu.A & 0xFF;
break;
case REG_AH:
ocpu.A++;
ocpu.AH = ocpu.A >> 8;
break;
case REG_A:
ocpu.A++;
break;
case REG_BL:
ocpu.B++;
ocpu.BL = ocpu.B & 0xFF;
break;
case REG_BH:
ocpu.B++;
ocpu.BH = ocpu.B >> 8;
break;
case REG_B:
ocpu.B++;
break;
case REG_CL:
ocpu.C++;
ocpu.CL = ocpu.C & 0xFF;
break;
case REG_CH:
ocpu.C++;
ocpu.CH = ocpu.C >> 8;
break;
case REG_C:
ocpu.C++;
break;
case REG_DL:
ocpu.D++;
ocpu.DL = ocpu.D & 0xFF;
break;
case REG_DH:
ocpu.D++;
ocpu.DH = ocpu.D >> 8;
break;
case REG_D:
ocpu.D++;
break;
case REG_EL:
ocpu.E++;
ocpu.EL = ocpu.E & 0xFF;
break;
case REG_EH:
ocpu.E++;
ocpu.EH = ocpu.E >> 8;
break;
case REG_E:
ocpu.E++;
break;
case REG_FL:
ocpu.F++;
ocpu.FL = ocpu.F & 0xFF;
break;
case REG_FH:
ocpu.F++;
ocpu.FH = ocpu.F >> 8;
break;
case REG_F:
ocpu.F++;
break;
default:
printf("Wrong register: %02X\n", reg);
return;
}
break;
case INS_DEC:
reg = ocpu_fetch_byte();
switch(reg) {
case REG_AL:
ocpu.A--;
ocpu.AL = ocpu.A & 0xFF;
break;
case REG_AH:
ocpu.A--;
ocpu.AH = ocpu.A >> 8;
break;
case REG_A:
ocpu.A--;
break;
case REG_BL:
ocpu.B--;
ocpu.BL = ocpu.B & 0xFF;
break;
case REG_BH:
ocpu.B--;
ocpu.BH = ocpu.B >> 8;
break;
case REG_B:
ocpu.B--;
break;
case REG_CL:
ocpu.C--;
ocpu.CL = ocpu.C & 0xFF;
break;
case REG_CH:
ocpu.C--;
ocpu.CH = ocpu.C >> 8;
break;
case REG_C:
ocpu.C--;
break;
case REG_DL:
ocpu.D--;
ocpu.DL = ocpu.D & 0xFF;
break;
case REG_DH:
ocpu.D--;
ocpu.DH = ocpu.D >> 8;
break;
case REG_D:
ocpu.D--;
break;
case REG_EL:
ocpu.E--;
ocpu.EL = ocpu.E & 0xFF;
break;
case REG_EH:
ocpu.E--;
ocpu.EH = ocpu.E >> 8;
break;
case REG_E:
ocpu.E--;
break;
case REG_FL:
ocpu.F--;
ocpu.FL = ocpu.F & 0xFF;
break;
case REG_FH:
ocpu.F--;
ocpu.FH = ocpu.F >> 8;
break;
case REG_F:
ocpu.F--;
break;
default:
printf("Wrong register: %02X\n", reg);
return;
}
break;
case INS_OCPU_NOP:
break;
case 0x00:
return;
default:
printf("Unrecognized instruction: %04X\n", instruction);
return;
}
}
}
void initOCPU(FILE *infile) {
ocpu_reset();
int ch;
int pos = 0;
while (1) { // FIXME
ch = fgetc(infile);
if (ch == EOF)
break;
ocpu_mem.memory[pos] = ch;
pos++;
}
ocpu_execute();
ocpu_dump_ocpu(ocpu);
return;
}
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