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Files
h8-536-decoder/h8536/decoder.py
2026-05-25 13:40:07 +10:00

501 lines
19 KiB
Python

from __future__ import annotations
from collections.abc import Iterable
from .formatting import (
bit_comment,
control_reg,
disp_text,
h8,
h16,
h24,
label_or_h,
reg_list,
s8,
s16,
write_comment,
)
from .model import EA, Instruction
from .rom import DecodeError, Rom
from .tables import BRANCH_NAMES, IO_REGISTERS
class H8536Decoder:
def __init__(self, rom: Rom, br: int | None = None, labels: dict[int, str] | None = None) -> None:
self.rom = rom
self.br = br
self.labels = labels if labels is not None else {}
def symbol(self, address: int) -> str:
if address in self.labels:
return self.labels[address]
if address in IO_REGISTERS:
return IO_REGISTERS[address]
return h16(address)
def mem(self, address: int) -> str:
return "@" + self.symbol(address)
def short_abs_address(self, low: int) -> int | None:
if self.br is None:
return None
return ((self.br & 0xFF) << 8) | (low & 0xFF)
def short_abs(self, low: int) -> str:
address = self.short_abs_address(low)
if address is None:
return f"@BR:{h8(low)}"
return self.mem(address)
def decode_ea(self, address: int) -> EA:
b = self.rom.u8(address)
if 0xA0 <= b <= 0xAF:
size = "W" if b & 0x08 else "B"
reg = b & 0x07
return EA(f"R{reg}", "reg", size, 1, reg=reg)
if 0xB0 <= b <= 0xBF:
size = "W" if b & 0x08 else "B"
reg = b & 0x07
return EA(f"@-R{reg}", "predec", size, 1, reg=reg)
if 0xC0 <= b <= 0xCF:
size = "W" if b & 0x08 else "B"
reg = b & 0x07
return EA(f"@R{reg}+", "postinc", size, 1, reg=reg)
if 0xD0 <= b <= 0xDF:
size = "W" if b & 0x08 else "B"
reg = b & 0x07
return EA(f"@R{reg}", "indirect", size, 1, reg=reg)
if 0xE0 <= b <= 0xEF:
size = "W" if b & 0x08 else "B"
reg = b & 0x07
disp = self.rom.u8(address + 1)
return EA(f"@({disp_text(s8(disp))},R{reg})", "disp8", size, 2, reg=reg, value=s8(disp))
if 0xF0 <= b <= 0xFF:
size = "W" if b & 0x08 else "B"
reg = b & 0x07
disp = self.rom.u16(address + 1)
return EA(f"@({disp_text(s16(disp))},R{reg})", "disp16", size, 3, reg=reg, value=s16(disp))
if b == 0x04:
value = self.rom.u8(address + 1)
return EA(f"#{h8(value)}", "imm", "B", 2, value=value)
if b == 0x0C:
value = self.rom.u16(address + 1)
return EA(f"#{h16(value)}", "imm", "W", 3, value=value)
if b in (0x05, 0x0D):
size = "W" if b == 0x0D else "B"
low = self.rom.u8(address + 1)
full = self.short_abs_address(low)
text = self.short_abs(low)
return EA(text, "abs8", size, 2, value=low, address=full)
if b in (0x15, 0x1D):
size = "W" if b == 0x1D else "B"
full = self.rom.u16(address + 1)
return EA(self.mem(full), "abs16", size, 3, address=full)
raise DecodeError(f"not an EA byte: {h8(b)}")
def decode(self, address: int) -> Instruction:
try:
b = self.rom.u8(address)
except DecodeError:
return Instruction(address, b"", ".eof", kind="invalid", fallthrough=False, valid=False)
if is_ea_byte(b):
try:
return self.decode_general(address)
except DecodeError:
pass
try:
return self.decode_direct(address)
except DecodeError:
raw = self.rom.slice(address, 1)
return Instruction(address, raw, ".db", h8(raw[0]), kind="invalid", fallthrough=False, valid=False)
def decode_general(self, address: int) -> Instruction:
ea = self.decode_ea(address)
op_addr = address + ea.length
op = self.rom.u8(op_addr)
end = op_addr + 1
mnemonic = ""
operands = ""
comment = ""
writes_br = False
br_value: int | None = None
source_to_reg = {
0x20: "ADD:G",
0x28: "ADDS",
0x30: "SUB",
0x38: "SUBS",
0x40: "OR",
0x50: "AND",
0x60: "XOR",
0x70: "CMP:G",
0x80: "MOV:G",
0xA0: "ADDX",
0xA8: "MULXU",
0xB0: "SUBX",
0xB8: "DIVXU",
}
base = op & 0xF8
rd = op & 0x07
if base in source_to_reg:
mnemonic = f"{source_to_reg[base]}.{ea.size}"
operands = f"{ea.text}, R{rd}"
elif base == 0x90:
rs = op & 0x07
if ea.mode == "reg":
mnemonic = "XCH.W"
operands = f"R{ea.reg}, R{rs}"
else:
mnemonic = f"MOV:G.{ea.size}"
operands = f"R{rs}, {ea.text}"
comment = write_comment(ea, None)
elif op in (0x10, 0x11, 0x12) and ea.mode == "reg":
names = {0x10: "SWAP.B", 0x11: "EXTS.B", 0x12: "EXTU.B"}
mnemonic = names[op]
operands = ea.text
elif op in (0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F):
unary = {
0x13: "CLR",
0x14: "NEG",
0x15: "NOT",
0x16: "TST",
0x17: "TAS",
0x18: "SHAL",
0x19: "SHAR",
0x1A: "SHLL",
0x1B: "SHLR",
0x1C: "ROTL",
0x1D: "ROTR",
0x1E: "ROTXL",
0x1F: "ROTXR",
}
size = "B" if op == 0x17 else ea.size
mnemonic = f"{unary[op]}.{size}"
operands = ea.text
elif op in (0x08, 0x09, 0x0C, 0x0D):
q = {0x08: 1, 0x09: 2, 0x0C: -1, 0x0D: -2}[op]
mnemonic = f"ADD:Q.{ea.size}"
operands = f"#{q}, {ea.text}"
comment = write_comment(ea, None)
elif op in (0x06, 0x07):
if op == 0x06:
imm = self.rom.u8(end)
end += 1
imm_text = h8(imm)
size = ea.size
else:
imm = self.rom.u16(end)
end += 2
imm_text = h16(imm)
size = "W"
mnemonic = f"MOV:G.{size}"
operands = f"#{imm_text}, {ea.text}"
comment = write_comment(ea, imm)
elif op in (0x04, 0x05):
if op == 0x04:
imm = self.rom.u8(end)
end += 1
imm_text = h8(imm)
size = "B"
else:
imm = self.rom.u16(end)
end += 2
imm_text = h16(imm)
size = "W"
mnemonic = f"CMP:G.{size}"
operands = f"#{imm_text}, {ea.text}"
elif op == 0x00:
ext = self.rom.u8(end)
end += 1
ext_base = ext & 0xF8
if ext_base == 0x80:
mnemonic = "MOVFPE.B"
operands = f"{ea.text}, R{ext & 7}"
elif ext_base == 0x90:
mnemonic = "MOVTPE.B"
operands = f"R{ext & 7}, {ea.text}"
comment = write_comment(ea, None)
else:
raise DecodeError(f"unknown extended general op {h8(ext)} after {h8(op)}")
elif (op & 0xF0) in (0xC0, 0xD0, 0xE0, 0xF0):
bit_ops = {0xC0: "BSET", 0xD0: "BCLR", 0xE0: "BNOT", 0xF0: "BTST"}
mnemonic = f"{bit_ops[op & 0xF0]}.{ea.size}"
operands = f"#{op & 0x0F}, {ea.text}"
if op & 0xF0 in (0xC0, 0xD0, 0xE0):
comment = bit_comment(mnemonic, ea, op & 0x0F)
elif base in (0x48, 0x58, 0x68, 0x78) and ea.mode != "imm":
bit_ops = {0x48: "BSET", 0x58: "BCLR", 0x68: "BNOT", 0x78: "BTST"}
mnemonic = f"{bit_ops[base]}.{ea.size}"
operands = f"R{rd}, {ea.text}"
elif base == 0x88:
mnemonic = f"LDC.{ea.size}"
operands = f"{ea.text}, {control_reg(rd, ea.size)}"
if rd == 1 and ea.size == "B":
writes_br = True
br_value = ea.value if ea.mode == "imm" else None
if br_value is not None:
comment = f"BR = {h8(br_value)}; @aa:8 upper address byte"
elif base == 0x98:
mnemonic = f"STC.{ea.size}"
operands = f"{control_reg(rd, ea.size)}, {ea.text}"
comment = write_comment(ea, None)
elif ea.mode == "imm" and base in (0x48, 0x58, 0x68):
ctrl_ops = {0x48: "ORC", 0x58: "ANDC", 0x68: "XORC"}
mnemonic = f"{ctrl_ops[base]}.{ea.size}"
operands = f"{ea.text}, {control_reg(rd, ea.size)}"
else:
raise DecodeError(f"unknown general op {h8(op)} after {h8(self.rom.u8(address))}")
raw = self.rom.slice(address, end - address)
references = [ea.address] if ea.address is not None else []
return Instruction(
address,
raw,
mnemonic,
operands,
comment=comment,
references=references,
writes_br=writes_br,
br_value=br_value,
)
def decode_direct(self, address: int) -> Instruction:
b = self.rom.u8(address)
if b == 0x00:
return self.ins(address, 1, "NOP")
if b == 0x02:
mask = self.rom.u8(address + 1)
return self.ins(address, 2, "LDM.W", f"@SP+, {reg_list(mask)}")
if b == 0x12:
mask = self.rom.u8(address + 1)
return self.ins(address, 2, "STM.W", f"{reg_list(mask)}, @-SP")
if b == 0x03:
page = self.rom.u8(address + 1)
pc = self.rom.u16(address + 2)
return self.ins(address, 4, "PJSR", f"@{h24((page << 16) | pc)}", "call", [pc])
if b == 0x13:
page = self.rom.u8(address + 1)
pc = self.rom.u16(address + 2)
return self.ins(address, 4, "PJMP", f"@{h24((page << 16) | pc)}", "jump", [pc], False)
if b in (0x01, 0x06, 0x07):
op2 = self.rom.u8(address + 1)
if 0xB8 <= op2 <= 0xBF:
disp = s8(self.rom.u8(address + 2))
target = (address + 3 + disp) & 0xFFFF
cond = {0x01: "F", 0x06: "NE", 0x07: "EQ"}[b]
return self.ins(
address,
3,
f"SCB/{cond}",
f"R{op2 & 7}, {label_or_h(target, self.labels)}",
"branch",
[target],
True,
)
if b == 0x08:
op2 = self.rom.u8(address + 1)
if (op2 & 0xF0) == 0x10:
return self.ins(address, 2, "TRAPA", f"#{op2 & 0x0F}")
if b == 0x09:
return self.ins(address, 1, "TRAP/VS")
if b == 0x0A:
return self.ins(address, 1, "RTE", kind="rte", fallthrough=False)
if b == 0x0E:
disp = s8(self.rom.u8(address + 1))
target = (address + 2 + disp) & 0xFFFF
return self.ins(address, 2, "BSR", label_or_h(target, self.labels), "call", [target])
if b == 0x0F:
return self.ins(address, 1, "UNLK", "FP")
if b == 0x10:
target = self.rom.u16(address + 1)
return self.ins(address, 3, "JMP", f"@{label_or_h(target, self.labels)}", "jump", [target], False)
if b == 0x11:
return self.decode_11(address)
if b == 0x14:
value = self.rom.u8(address + 1)
return self.ins(address, 2, "RTD", f"#{h8(value)}", "return", fallthrough=False)
if b == 0x17:
value = self.rom.u8(address + 1)
return self.ins(address, 2, "LINK", f"FP, #{h8(value)}")
if b == 0x18:
target = self.rom.u16(address + 1)
return self.ins(address, 3, "JSR", f"@{label_or_h(target, self.labels)}", "call", [target])
if b == 0x19:
return self.ins(address, 1, "RTS", kind="return", fallthrough=False)
if b == 0x1A:
return self.ins(address, 1, "SLEEP", kind="sleep", fallthrough=False)
if b == 0x1C:
value = self.rom.u16(address + 1)
return self.ins(address, 3, "RTD", f"#{h16(value)}", "return", fallthrough=False)
if b == 0x1E:
disp = s16(self.rom.u16(address + 1))
target = (address + 3 + disp) & 0xFFFF
return self.ins(address, 3, "BSR", label_or_h(target, self.labels), "call", [target])
if b == 0x1F:
value = self.rom.u16(address + 1)
return self.ins(address, 3, "LINK", f"FP, #{h16(value)}")
if 0x20 <= b <= 0x2F:
cond = b & 0x0F
disp = s8(self.rom.u8(address + 1))
target = (address + 2 + disp) & 0xFFFF
fallthrough = BRANCH_NAMES[cond] not in ("BRA",)
kind = "jump" if BRANCH_NAMES[cond] == "BRA" else "branch"
return self.ins(address, 2, BRANCH_NAMES[cond], label_or_h(target, self.labels), kind, [target], fallthrough)
if 0x30 <= b <= 0x3F:
cond = b & 0x0F
disp = s16(self.rom.u16(address + 1))
target = (address + 3 + disp) & 0xFFFF
fallthrough = BRANCH_NAMES[cond] not in ("BRA",)
kind = "jump" if BRANCH_NAMES[cond] == "BRA" else "branch"
return self.ins(address, 3, BRANCH_NAMES[cond], label_or_h(target, self.labels), kind, [target], fallthrough)
if 0x40 <= b <= 0x47:
rd = b & 7
imm = self.rom.u8(address + 1)
return self.ins(address, 2, "CMP:E", f"#{h8(imm)}, R{rd}")
if 0x48 <= b <= 0x4F:
rd = b & 7
imm = self.rom.u16(address + 1)
return self.ins(address, 3, "CMP:I", f"#{h16(imm)}, R{rd}")
if 0x50 <= b <= 0x57:
rd = b & 7
imm = self.rom.u8(address + 1)
return self.ins(address, 2, "MOV:E.B", f"#{h8(imm)}, R{rd}")
if 0x58 <= b <= 0x5F:
rd = b & 7
imm = self.rom.u16(address + 1)
return self.ins(address, 3, "MOV:I.W", f"#{h16(imm)}, R{rd}")
if 0x60 <= b <= 0x67:
rd = b & 7
low = self.rom.u8(address + 1)
ref = self.short_abs_address(low)
return self.ins(
address,
2,
"MOV:L.B",
f"{self.short_abs(low)}, R{rd}",
references=[ref] if ref is not None else None,
)
if 0x68 <= b <= 0x6F:
rd = b & 7
low = self.rom.u8(address + 1)
ref = self.short_abs_address(low)
return self.ins(
address,
2,
"MOV:L.W",
f"{self.short_abs(low)}, R{rd}",
references=[ref] if ref is not None else None,
)
if 0x70 <= b <= 0x77:
rs = b & 7
low = self.rom.u8(address + 1)
ref = self.short_abs_address(low)
ea = EA(self.short_abs(low), "abs8", "B", 2, value=low, address=ref)
return self.ins(
address,
2,
"MOV:S.B",
f"R{rs}, {ea.text}",
references=[ref] if ref is not None else None,
comment=write_comment(ea, None),
)
if 0x78 <= b <= 0x7F:
rs = b & 7
low = self.rom.u8(address + 1)
ref = self.short_abs_address(low)
ea = EA(self.short_abs(low), "abs8", "W", 2, value=low, address=ref)
return self.ins(
address,
2,
"MOV:S.W",
f"R{rs}, {ea.text}",
references=[ref] if ref is not None else None,
comment=write_comment(ea, None),
)
if 0x80 <= b <= 0x87:
rd = b & 7
disp = s8(self.rom.u8(address + 1))
return self.ins(address, 2, "MOV:F.B", f"@({disp_text(disp)},R6), R{rd}")
if 0x88 <= b <= 0x8F:
rd = b & 7
disp = s8(self.rom.u8(address + 1))
return self.ins(address, 2, "MOV:F.W", f"@({disp_text(disp)},R6), R{rd}")
if 0x90 <= b <= 0x97:
rs = b & 7
disp = s8(self.rom.u8(address + 1))
return self.ins(address, 2, "MOV:F.B", f"R{rs}, @({disp_text(disp)},R6)")
if 0x98 <= b <= 0x9F:
rs = b & 7
disp = s8(self.rom.u8(address + 1))
return self.ins(address, 2, "MOV:F.W", f"R{rs}, @({disp_text(disp)},R6)")
raise DecodeError(f"unknown direct opcode {h8(b)}")
def decode_11(self, address: int) -> Instruction:
op = self.rom.u8(address + 1)
if op == 0x14:
value = self.rom.u8(address + 2)
return self.ins(address, 3, "PRTD", f"#{h8(value)}", "return", fallthrough=False)
if op == 0x19:
return self.ins(address, 2, "PRTS", kind="return", fallthrough=False)
if op == 0x1C:
value = self.rom.u16(address + 2)
return self.ins(address, 4, "PRTD", f"#{h16(value)}", "return", fallthrough=False)
if 0xC0 <= op <= 0xC7:
return self.ins(address, 2, "PJMP", f"@R{op & 7}", "jump", fallthrough=False)
if 0xC8 <= op <= 0xCF:
return self.ins(address, 2, "PJSR", f"@R{op & 7}", "call")
if 0xD0 <= op <= 0xD7:
return self.ins(address, 2, "JMP", f"@R{op & 7}", "jump", fallthrough=False)
if 0xD8 <= op <= 0xDF:
return self.ins(address, 2, "JSR", f"@R{op & 7}", "call")
if 0xE0 <= op <= 0xE7:
disp = s8(self.rom.u8(address + 2))
return self.ins(address, 3, "JMP", f"@({disp_text(disp)},R{op & 7})", "jump", fallthrough=False)
if 0xE8 <= op <= 0xEF:
disp = s8(self.rom.u8(address + 2))
return self.ins(address, 3, "JSR", f"@({disp_text(disp)},R{op & 7})", "call")
if 0xF0 <= op <= 0xF7:
disp = s16(self.rom.u16(address + 2))
return self.ins(address, 4, "JMP", f"@({disp_text(disp)},R{op & 7})", "jump", fallthrough=False)
if 0xF8 <= op <= 0xFF:
disp = s16(self.rom.u16(address + 2))
return self.ins(address, 4, "JSR", f"@({disp_text(disp)},R{op & 7})", "call")
raise DecodeError(f"unknown 0x11 opcode {h8(op)}")
def ins(
self,
address: int,
size: int,
mnemonic: str,
operands: str = "",
kind: str = "normal",
targets: Iterable[int] | None = None,
fallthrough: bool = True,
references: Iterable[int] | None = None,
comment: str = "",
writes_br: bool = False,
br_value: int | None = None,
) -> Instruction:
return Instruction(
address,
self.rom.slice(address, size),
mnemonic,
operands,
kind=kind,
targets=list(targets or []),
fallthrough=fallthrough,
comment=comment,
references=list(references or []),
writes_br=writes_br,
br_value=br_value,
)
def is_ea_byte(value: int) -> bool:
return value in (0x04, 0x05, 0x0C, 0x0D, 0x15, 0x1D) or 0xA0 <= value <= 0xFF