Disassembler - Z80

opcode_map = 0x00: ("NOP", 1), 0x01: ("LD BC, $%04X", 3), 0xC3: ("JP $%04X", 3), # ... full table omitted for brevity

To understand a Z80 binary—whether to reverse-engineer a classic game, patch a ROM, or debug vintage firmware—you need a disassembler. But a disassembler is not merely a "binary-to-text" converter. It is a lens through which we reconstruct intent, control flow, and data structures from raw machine code.

def recursive_disassemble(start, memory, visited): pc = start while pc < len(memory) and pc not in visited: visited.add(pc) insn, length = decode_one(pc, memory) print(f"pc:04X: insn") # simplistic flow analysis if "JP" in insn and "$" in insn: target = int(insn.split("$")[1], 16) if target not in visited: recursive_disassemble(target, memory, visited) break # unconditional jump elif "RET" in insn or "RETI" in insn or "RETN" in insn: break else: pc += length z80 disassembler

In the world of retrocomputing, a reliable Z80 disassembler is a time machine. It lets you peer into the minds of 1980s programmers, decode their clever memory-saving tricks, and preserve digital history—one opcode at a time.

def decode_one(pc, memory): op = memory[pc] if op in opcode_map: mnemonic, length = opcode_map[op] if length == 3: operand = memory[pc+1] | (memory[pc+2] << 8) return (mnemonic % operand, length) return (mnemonic, length) else: return (".db $%02X" % op, 1) opcode_map = 0x00: ("NOP", 1), 0x01: ("LD BC,

“To disassemble is to understand; to understand is to preserve.”

Pseudo-structure in C:

1. Introduction: Why the Z80 Still Matters The Zilog Z80, introduced in 1976, is one of the most influential microprocessors in history. It powered everything from the Game Boy (custom LR35902, a Z80 derivative) and the Sega Master System to the Sinclair ZX Spectrum, Amstrad CPC, MSX, and countless arcade machines. Even today, it thrives in embedded systems, retrocomputing, and hobbyist scenes.