def parse_instructions(f):
instr_lst = []
yaml_obj = yaml.load(open(f, 'r').read(), Loader=Loader)
for instr in yaml_obj['instructions']:
name = instr['name']
opcode = instr['opcode']
if opcode > 63:
raise Exception("Invalid Opcode: %i" % opcode)
instr_desc = instr['description']
operand = bool(instr['requires_operand'])
instruction = Instruction(name, opcode, instr_desc, operand)
for key in instr['flags'].keys():
if key.lower() not in ['other', 'cf', 'zf', 'pf']:
raise Exception("Invalid Flag: %s" % key)
for step in instr['flags'][key]:
sigs = step['signals']
if sigs is None:
sigs = []
else:
new_sigs = []
for sig in sigs:
new_sigs.append(CtrlSigs[sig])
sigs = new_sigs
step_desc = step['description']
microstep = MicroStep(sigs, step_desc)
instruction.insert_step(microstep, key)
instr_lst.append(instruction)
return instr_lst
from classes import Instruction, CtrlSigs, MicroStep
instr_lst = []
# No Operation
NOP = Instruction('NOP', 0b000000, "Do absolutely nothing")
NOP.insert_step(MicroStep([], "Do absolutely nothing"))
instr_lst.append(NOP)
# A Load instructions
LDA = Instruction('LDA', 0b000001, "Load RAM contents to Register A", True)
LDA.insert_step(MicroStep([CtrlSigs.IO, CtrlSigs.MI], "Move IR Address to MAR"))
LDA.insert_step(MicroStep([CtrlSigs.RO, CtrlSigs.AI], "Move RAM contents to reg. A"))
instr_lst.append(LDA)
LAI = Instruction('LAI', 0b000010, "Load a value to Register A immediately", True)
LAI.insert_step(MicroStep([CtrlSigs.IO, CtrlSigs.AI], "Move IR value to reg. A"))
instr_lst.append(LAI)
# B Load Instructions
LDB = Instruction('LDB', 0b000011, "Load RAM contents to Register B", True)
LDB.insert_step(MicroStep([CtrlSigs.IO, CtrlSigs.MI], "Move IR contetns to MAR"))
LDB.insert_step(MicroStep([CtrlSigs.RO, CtrlSigs.BI], "Move RAM contents to reg. B"))
instr_lst.append(LDB)
LBI = Instruction('LBI', 0b000100, "Load a value to Register B immediately, True)
LBI.insert_step(MicroStep([CtrlSigs.IO, CtrlSigs.BI], "Move IR value to reg. B"))
instr_lst.append(LBI)
# C Load Instructions
LDC = Instruction('LDC', 0b000101, "Load RAM contents to Register C", True)