ii-sound/opcodes_6502.py

from typing import Iterable, Tuple


class Opcode:
    """6502 assembly language opcode with cycle length"""

    def __init__(self, cycles, bytes, asm="", indent=4, toggle=False):
        self.cycles = cycles
        self.bytes = bytes
        self.asm = asm
        self.indent = indent
        # Assume toggles speaker on the last cycle
        self.toggle = toggle

    def __repr__(self):
        asm = "[%s] " % self.asm if self.asm else ""
        return "%s<%d cycles>" % (asm, self.cycles)

    def __str__(self):
        indent = " " * self.indent
        comment = ' ; %d cycles' % self.cycles if self.cycles else ""
        return indent + self.asm + comment


class Literal(Opcode):
    def __init__(self, asm, indent=4):
        super(Literal, self).__init__(cycles=0, bytes=0, asm=asm, indent=indent)

    def __repr__(self):
        return "<literal>"


class PaddingOpcode(Opcode):
    """Opcode variant that can be replaced by other interleaved opcodes."""
    pass


def interleave_opcodes(
        base_opcodes: Iterable[Opcode],
        interleaved_opcodes: Iterable[Opcode]) -> Iterable[Opcode]:
    for op in base_opcodes:
        if isinstance(op, PaddingOpcode):
            padding_cycles = op.cycles

            while padding_cycles > 0:
                if interleaved_opcodes:
                    interleaved_op = interleaved_opcodes[0]
                    if (padding_cycles - interleaved_op.cycles) >= 0 and (
                            padding_cycles - interleaved_op.cycles) != 1:
                        yield interleaved_op
                        padding_cycles -= interleaved_op.cycles
                        interleaved_opcodes = interleaved_opcodes[1::]
                        if not interleaved_opcodes:
                            return
                        continue
                if padding_cycles == 3:
                    yield PaddingOpcode(3, 2, "STA zpdummy")
                    padding_cycles -= 3
                else:
                    yield PaddingOpcode(2, 1, "NOP")
                    padding_cycles -= 2
            assert padding_cycles == 0
        else:
            yield op
    if interleaved_opcodes:
        print(interleaved_opcodes)
        raise OverflowError


STA_C030 = Opcode(4, 3, "STA $C030", toggle=True)
# TODO: support 6502 cycle timings (5 cycles instead of 6)
JMP_WDATA = Opcode(6, 3, "JMP (WDATA)")

def padding(cycles):
    return PaddingOpcode(cycles, None, "; pad %d cycles" % cycles)


def nops(cycles: int) -> Iterable[Opcode]:
    if cycles < 2:
        raise ValueError
    while cycles:
        if cycles == 3:
            yield Opcode(3, 2, "STA zpdummy")
            cycles -= 3
            continue
        yield Opcode(2, 1, "NOP")
        cycles -= 2


# def voltage_sequence(
#         opcodes: Iterable[Opcode], starting_voltage=1.0
# ) -> Tuple[numpy.float32, int]:
#     """Voltage sequence for sequence of opcodes."""
#     out = []
#     v = starting_voltage
#     toggles = 0
#     for op in opcodes:
#         for nv in v * numpy.array(VOLTAGES[op]):
#             if v != nv:
#                 toggles += 1
#             v = nv
#             out.append(v)
#     return tuple(numpy.array(out, dtype=numpy.float32)), toggles


def toggles(opcodes: Iterable[Opcode]) -> Tuple[float]:
    res = []
    speaker = 1.0
    for op in opcodes:
        if not op.cycles:
            continue
        res.extend([speaker] * (op.cycles - 1))
        if op.toggle:
            speaker *= -1
        res.append(speaker)
    return tuple(res)


def total_bytes(opcodes: Iterable[Opcode]) -> int:
    return sum(op.bytes for op in opcodes)


def total_cycles(opcodes: Iterable[Opcode]) -> int:
    return sum(op.cycles for op in opcodes)