udis/udis.py
2015-07-02 22:03:50 -04:00

238 lines
7.9 KiB
Python
Executable File

#! /usr/bin/env python3
#
# Universal Disassembler
# Copyright (c) 2013-2015 by Jeff Tranter <tranter@pobox.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
import sys
import fileinput
import argparse
import signal
# Flags
pcr = 1
# Functions
def isprint(c):
"Return if character is printable ASCII"
if c >= '@' and c <= '~':
return True
else:
return False
# Avoids an error when output piped, e.g. to "less"
signal.signal(signal.SIGPIPE, signal.SIG_DFL)
# Parse command line options
parser = argparse.ArgumentParser()
parser.add_argument("filename", help="Binary file to disassemble")
parser.add_argument("-c", "--cpu", help="Specify CPU type (defaults to 6502)", default="6502")
parser.add_argument("-n", "--nolist", help="Don't list instruction bytes (make output suitable for assembler)", action="store_true")
parser.add_argument("-a", "--address", help="Specify decimal starting address (defaults to 0)", default=0, type=int)
parser.add_argument("-i", "--invalid", help="Show invalid opcodes as ??? rather than constants", action="store_true")
args = parser.parse_args()
# Load CPU plugin based on command line option.
# Looks for plugin in same directory as this program.
dir = os.path.dirname(os.path.realpath(__file__))
plugin = dir + os.sep + args.cpu + ".py"
try:
exec(open(plugin).read())
except FileNotFoundError:
print(("error: CPU plugin file '{}' not found.".format(plugin)), file=sys.stderr)
print("The following CPUs are supported: 6502 65c02 6800 6811 8080 z80")
sys.exit(1)
# Get filename from command line arguments.
filename = args.filename
# Current instruction address. Silently force it to be in valid range.
address = args.address & 0xffff
# Any flags for current instruction.
flags = 0
# Contains a line of output.
line = ""
# Open input file.
# Display error and exit if filename does not exist.
try:
f = open(filename, "rb")
except FileNotFoundError:
print(("error: input file '{}' not found.".format(filename)), file=sys.stderr)
sys.exit(1)
# Variables:
# address - current instruction address
# opcode - binary instruction opcode (may be multiple bytes)
# length - length of current instruction
# mnemonic - assembler mnemonic for current instruction
# format - operand format string
# line - line to output
# leadin - extended opcode (true/false)
s = " "
# Print initial origin address
if args.nolist is False:
print("{0:04X}{1:s}.org ${2:04X}".format(address, s[0:maxLength*3+3], address))
else:
print(" .org ${0:04X}".format(address))
while True:
try:
b = f.read(1) # Get binary byte from file
if len(b) == 0: # handle EOF
if args.nolist is False:
print("{0:04X}{1:s}end".format(address, s[0:maxLength*3+3]))
break
# Get op code
opcode = ord(b)
# Handle if opcode is a leadin byte
if opcode in leadInBytes:
b = f.read(1) # Get next byte of extended opcode
if len(b) == 0: # Unexpected EOF
break
opcode = (opcode << 8) + ord(b)
leadin = True
else:
leadin = False
# Given opcode, get data from opcode table and address mode table for CPU.
if opcode in opcodeTable:
length = opcodeTable[opcode][0]
mnemonic = opcodeTable[opcode][1]
mode = opcodeTable[opcode][2]
if len(opcodeTable[opcode]) > 3:
flags = opcodeTable[opcode][3] # Get optional flags
else:
flags = 0
if mode in addressModeTable:
format = addressModeTable[mode]
else:
print(("error: mode '{}' not found in addressModeTable.".format(mode)), file=sys.stderr)
sys.exit(1)
else:
length = 1 # Invalid opcode
format = ""
mnemonic = "???"
# Disassembly format:
# XXXX XX XX XX XX XX nop ($1234,X)
# With --nolist option:
# nop ($1234,X)
# Add current address to output line
if args.nolist is False:
if leadin is True:
line += "{0:04X} {1:02X} {2:02X}".format(address, opcode // 256, opcode % 256)
length -= 1
else:
line += "{0:04X} {1:02X}".format(address, opcode)
op = {} # Array to hold operands
# Get any operands and store in an array
for i in range(1, maxLength):
if (i < length):
b = f.read(1)
if len(b) == 0: # Unexpected EOF
break
op[i] = ord(b) # Get operand bytes
if args.nolist is False:
line += " {0:02X}".format(op[i])
else:
if args.nolist is False and leadin is False and i != length-1:
line += " "
if len(b) == 0: # Unexpected EOF
break
# Handle relative addresses. Indicated by the flag pcr being set.
# Assumes the operand that needs to be PC relative is the last one.
# Note: Code will need changes if more flags are added.
if flags == pcr:
if op[length-1] < 128:
op[length-1] = address + op[length-1] + length
else:
op[length-1] = address - (256 - op[length-1]) + length
if op[length-1] < 0:
op[length-1] = 65536 + op[length-1]
# Format the operand using format string and any operands.
if length == 1:
operand = format
elif length == 2:
operand = format.format(op[1])
elif length == 3:
operand = format.format(op[1], op[2])
elif length == 4:
operand = format.format(op[1], op[2], op[3])
elif length == 5:
operand = format.format(op[1], op[2], op[3], op[4])
elif length == 6:
operand = format.format(op[1], op[2], op[3], op[4], op[5])
elif length == 7:
operand = format.format(op[1], op[2], op[3], op[4], op[5], op[6])
# Special check for invalid op code. Display as ??? or .byte depending on command line option.
if mnemonic == "???" and not args.invalid:
# Handle case where invalid opcode has a leadin byte.
if leadin is True:
if args.nolist is False:
mnemonic = "{0:s}.byte ${1:02X},${2:02X}".format(s[0:(maxLength-length-2)*3], opcode // 256, opcode % 256)
else:
mnemonic = ".byte ${0:02X},${1:02X}".format(opcode // 256, opcode % 256)
else:
if isprint(chr(opcode)):
mnemonic = ".byte '{0:c}'".format(opcode)
else:
mnemonic = ".byte ${0:02X}".format(opcode)
# Need one more space if not in no list mode.
if args.nolist is False:
line += " "
# Add mnemonic and any operands to the output line.
if operand == "":
line += " {0:s}".format(mnemonic)
else:
line += " {0:5s} {1:s}".format(mnemonic, operand)
# Print line of output
print(line)
# Update address, handlng wraparound at 64K.
address = (address + length) & 0xffff
# Reset variables for next line of output.
line = ""
operand = ""
flags = 0
except KeyboardInterrupt:
print("Interrupted by Control-C", file=sys.stderr)
break