pasm/interpreter.py

from ctypes import *
import time

RAM = []
for i in range(256):
    RAM.append(c_uint8(0))
PC, CB, RW, LM = c_uint16(0), c_uint16(0), c_uint16(0), c_uint16(0)
REG = c_uint16(0), c_uint16(0), c_uint16(0), c_uint16(0), c_uint16(0), c_uint16(0)
PROG = open("prog.bin", "rb").read()
HALTED = False
SPEED_HZ = 1600

instr_bytes = {
    0x00: 1,
    0x01: 2,
    0x0A: 3,
    0x0B: 3,
    0x0C: 3,
    0x0D: 3,
    0x0E: 3,
    0x0F: 3,
    0xFF: 3,
    0x02: 3,
    0x03: 2,
    0x04: 2,
    0x05: 3,
    0x06: 3,
    0x07: 3,
    0x08: 3,
    0x10: 2,
    0x11: 2,
    0x12: 2,
    0x13: 2,
    0x14: 2,
    0x15: 2,
    0x16: 2,
    0x17: 2,
    0x18: 2,
    0x19: 2,
    0x1A: 2,
    0x1B: 2,
    0x1C: 2,
    0x1D: 2,
    0x1E: 2,
    0x20: 1,
    0x21: 3,
    0x40: 2,
    0x41: 2,
    0x42: 2,
    0x43: 2,
    0x44: 2,
    0x45: 2,
    0x46: 2,
    0x47: 2,
    0x48: 2,
    0x30: 4,
    0x31: 4,
    0x32: 4,
    0x33: 4,
    0x34: 4,
    0x35: 4,
    0x36: 4,
    0x37: 4,
    0x38: 4
}

def read_16(byte1: int, byte2: int) -> c_uint16:
    return c_uint16((byte1 << 8) + byte2)


def debug():
    print()
    for i in range(0, len(RAM), 16):
        print(f"0x{format(i, "04X")}: ", end="")
        line = RAM[i:i + 16]
        print(
            " ".join(format(b.value, "02X") for b in line),
            "".join(chr(b.value) if b.value >= 0x20 else " " for b in line)
        )

    print("AX:", REG[0].value)
    print("BX:", REG[1].value)
    print("CX:", REG[2].value)
    print("DX:", REG[3].value)
    print("EX:", REG[4].value)
    print("FX:", REG[5].value)
    print("CB:", CB.value)
    print("LM:", LM.value)

while PC.value < len(PROG):
    instr = PROG[PC.value]
    if instr == 0xFF:
        RW = read_16(PROG[PC.value + 1], PROG[PC.value + 2])
    else:
        RAM[RW.value] = c_uint16(PROG[PC.value])
        for byte in PROG[PC.value + 1:PC.value + instr_bytes[instr]]:
            RW.value += 1
            RAM[RW.value] = c_uint16(byte)
        RW.value += 1
    PC.value += instr_bytes[instr]

PC.value = 0

while not HALTED and PC.value < len(RAM):
    start_time = time.time()
    instr = RAM[PC.value].value
    x, y, z = RAM[PC.value + 1].value >> 4, RAM[PC.value + 1].value & 15, RAM[PC.value + 3].value
    value = (RAM[PC.value + 1].value << 8) + RAM[PC.value + 2].value
    PC.value += instr_bytes[instr]

    if instr == 0x00:
        HALTED = True

    elif instr == 0x01:
        if x == y:
            REG[x - 10].value = 0
        else:
            REG[x - 10].value = REG[y - 10].value

    elif instr in [0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F]:
        REG[instr - 10].value = value

    elif instr == 0x02:
        PC.value = value

    elif instr == 0x03:
        PC.value = REG[y - 10].value

    elif instr == 0x04:
        if REG[x - 10].value == REG[y - 10].value: CB.value = 0
        elif REG[x - 10].value > REG[y - 10].value: CB.value = 1
        elif REG[x - 10].value < REG[y - 10].value: CB.value = 2

    elif instr == 0x05 and CB.value == 0:
        PC.value = value

    elif instr == 0x06 and CB.value != 0:
        PC.value = value

    elif instr == 0x07 and CB.value == 1:
        PC.value = value

    elif instr == 0x08 and CB.value == 2:
        PC.value = value

    elif instr == 0x10:
        REG[x - 10].value += REG[y - 10].value
    
    elif instr == 0x11:
        REG[x - 10].value -= REG[y - 10].value
    
    elif instr == 0x12:
        REG[y - 10].value += 1

    elif instr == 0x13:
        REG[y - 10].value -= 1

    elif instr == 0x14:
        REG[x - 10].value *= REG[y - 10].value
    
    elif instr == 0x15:
        REG[x - 10].value //= REG[y - 10].value

    elif instr == 0x16:
        REG[x - 10].value %= REG[y - 10].value

    elif instr == 0x17:
        REG[x - 10].value &= REG[y - 10].value

    elif instr == 0x18:
        REG[x - 10].value |= REG[y - 10].value

    elif instr == 0x19:
        REG[x - 10].value ^= REG[y - 10].value

    elif instr == 0x1A:
        REG[y - 10].value = (1 << 4) - 1 - REG[y - 10].value

    elif instr == 0x1B:
        REG[x - 10].value <<= REG[y - 10].value

    elif instr == 0x1C:
        REG[x - 10].value >>= REG[y - 10].value

    elif instr == 0x1D:
        val = REG[x - 10].value
        addr = REG[y - 10].value
        RAM[addr].value = val >> 8
        RAM[addr + 1].value = val & 255

    elif instr == 0x1E:
        addr = REG[y - 10].value
        REG[x - 10].value = (RAM[addr].value << 8) + RAM[addr + 1].value

    elif instr == 0x20:
        PC.value = LM.value

    elif instr == 0x21:
        LM.value = PC.value
        PC.value = value
    
    elif instr == 0x45:
        print(chr(REG[y - 10].value), end="")

    elif instr == 0x30:
        REG[z - 10].value += value

    elif instr == 0x31:
        REG[z - 10].value += value

    elif instr == 0x32:
        REG[z - 10].value *= value

    elif instr == 0x33:
        REG[z - 10].value //= value

    elif instr == 0x34:
        REG[z - 10].value %= value

    elif instr == 0x35:
        REG[z - 10].value <<= value

    elif instr == 0x36:
        REG[z - 10].value >>= value

    elif instr == 0x37:
        val = REG[z - 10].value
        RAM[value].value = val >> 8
        RAM[value + 1].value = val & 255

    elif instr == 0x38:
        REG[z - 10].value = (RAM[value].value << 8) + RAM[value + 1].value

    sleep_time = 1/SPEED_HZ - (time.time() - start_time )
    if sleep_time > 0:
        time.sleep(sleep_time)

debug()