int interp_control() {
uint32_t opcode = GET_OPCODE(if_id.inst);
uint32_t address;
switch (opcode) {
case OPCODE_R :
id_ex.reg_write = true;
id_ex.reg_dst = GET_RD(if_id.inst);
id_ex.rt = GET_RT(if_id.inst);
id_ex.rs_value = regs[GET_RS(if_id.inst)];
id_ex.rt_value = regs[id_ex.rt];
id_ex.funct = GET_FUNCT(if_id.inst);
id_ex.shamt = GET_SHAMT(if_id.inst);
if (id_ex.funct == FUNCT_JR) {
id_ex.jump = true;
id_ex.jump_target = id_ex.rs_value;
}
break;
case OPCODE_BEQ :
id_ex.branch = true;
id_ex.beq = true;
id_ex.rt = GET_RT(if_id.inst);
id_ex.rs_value = regs[GET_RS(if_id.inst)];
id_ex.rt_value = regs[id_ex.rt];
id_ex.sign_ext_imm = SIGN_EXTEND(GET_IMM(if_id.inst));
// INSTRUKTOR 0: no reason to updates fields that you dont use
id_ex.funct = FUNCT_SUB;
break;
case OPCODE_BNE :
id_ex.branch = true;
id_ex.beq = false;
id_ex.rt = GET_RT(if_id.inst);
id_ex.rs_value = regs[GET_RS(if_id.inst)];
id_ex.rt_value = regs[id_ex.rt];
id_ex.sign_ext_imm = SIGN_EXTEND(GET_IMM(if_id.inst));
id_ex.funct = FUNCT_SUB;
break;
case OPCODE_LW :
id_ex.mem_read = true;
id_ex.reg_write = true;
id_ex.alu_src = true;
id_ex.mem_to_reg = true;
id_ex.reg_dst = GET_RT(if_id.inst);
id_ex.rt = GET_RT(if_id.inst);
id_ex.rs_value = regs[GET_RS(if_id.inst)];
id_ex.rt_value = regs[id_ex.rt];
id_ex.sign_ext_imm = SIGN_EXTEND(GET_IMM(if_id.inst));
id_ex.funct = FUNCT_ADD;
break;
case OPCODE_SW :
id_ex.mem_write = true;
id_ex.alu_src = true;
id_ex.rt = GET_RT(if_id.inst);
id_ex.rs_value = regs[GET_RS(if_id.inst)];
id_ex.rt_value = regs[id_ex.rt];
id_ex.sign_ext_imm = SIGN_EXTEND(GET_IMM(if_id.inst));
id_ex.funct = FUNCT_ADD;
break;
case OPCODE_J :
id_ex.jump = true;
address = GET_ADDRESS(if_id.inst);
id_ex.jump_target = (if_id.next_pc & MS_4B) | (address << 2);
break;
case OPCODE_JAL :
id_ex.reg_write = true;
id_ex.jump = true;
address = GET_ADDRESS(if_id.inst);
id_ex.jump_target = (if_id.next_pc & MS_4B) | (address << 2);
id_ex.rs_value = 0;
id_ex.rt_value = if_id.next_pc;
id_ex.reg_dst = 31;
id_ex.funct = FUNCT_ADD;
break;
// INSTRUKTOR -2: Make cases for all I-type and J-type instructions
default:
printf("ERROR: Unknown opcode in interp_control()\n");
return ERROR_UNKNOWN_OPCODE;
}
return 0;
}
const void Cpu::executeImmOp(const uInt op){
#if DEBUGLEVEL > 2
printf("I-op, op:%x, r%d, r%d, imm:%x\n", GET_OPCODE(op), OP_SRC_REG(op), OP_ADD_REG(op), GET_IMM(op));
#endif
uInt* const add = &mips->r[OP_ADD_REG(op)];
const uInt* const src = &mips->r[OP_SRC_REG(op)];
const uInt pmem = *src + GET_IMMSGN(op);
switch (GET_OPCODE(op)){
case OPCODE_BEQ:
mips->pc += (*src == *add) ? GET_IMMSGN(op)*4 : 0;
break;
case OPCODE_BNE:
mips->pc += (*src != *add) ? GET_IMMSGN(op)*4 : 0;
break;
case OPCODE_ADDI:
//TODO throw overflow exception
case OPCODE_ADDIU:
*add = *src + GET_IMMSGN(op);
break;
case OPCODE_MFC:
fatalError("Unimplemented I-op\n");
case OPCODE_FP:
fatalError("In executeImmOp, but found FP-op!\n");
case OPCODE_SLTI:
*add = (sInt(*src) < GET_IMMSGN(op)) ? 1 : 0;
break;
case OPCODE_SLTIU:
*add = (*src < GET_IMMSGN(op)) ? 1 : 0;
break;
case OPCODE_ANDI:
*add = *src & GET_IMM(op);
break;
case OPCODE_ORI:
*add = *src | GET_IMM(op);
break;
case OPCODE_LUI:
*add = GET_IMM(op);
break;
case OPCODE_LW:
*add = mem->get<uInt>(pmem);
break;
case OPCODE_LD:
fatalError("Unimplemented I-op\n");
case OPCODE_LBU:
*add = mem->get<uChar>(pmem);
break;
case OPCODE_LHU:
*add = mem->get<uShort>(pmem);
break;
case OPCODE_SB:
mem->set(pmem, uChar(*add));
break;
case OPCODE_SH:
mem->set(pmem, uShort(*add));
break;
case OPCODE_LL:
fatalError("Unimplemented I-op\n");
case OPCODE_SW:
mem->set(pmem, *add);
break;
default:
fatalError("Unknown I-op instruction\n");
}
};
