239 lines
8.9 KiB
Python
Executable File
239 lines
8.9 KiB
Python
Executable File
#!/usr/bin/env python3
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# a simple assembler/disassembler for the n808 VM
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# supports both text and binary program formats
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# usage: n8asm [at|ab|dt|db|t2b|b2t|t74] file outfile
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# modes:
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# at: assemble to plaintext (N8) machine code
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# ab: assemble to binary (N8B) machine code
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# dt: disassemble plaintext (N8) machine code
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# db: disassemble binary (N8B) machine code
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# t2b: convert from plaintext N8 to binary N8B
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# b2t: convert from binary N8B to plaintext N8
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# t74: convert from plaintext N8 to the TI-74 representation
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# Created by Luxferre in 2025, released into public domain
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import sys, re, struct
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# n808 mnemonics for assembly and disasssembly
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mnemos = ['nop', 'jmp', 'iat', 'ino', 'cpy', 'set', 'mat', 'rnd']
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# n808 jump/function shortcuts (arranged from longest to shortest)
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jmpfunc_shorts = {
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'ret': 'jmp 13 0 125', # return from a procedure
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'nnn': 'nop 0 0 0', # alias for nop
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'inc': 'mat 0 127', # increment
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'dec': 'mat 0 126', # decrement
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'inv': 'mat 3 127', # inverse/reciprocal
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'iuc': 'jmp 13 0', # indirect unconditional jump
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'jpr': 'jmp 14 0', # jump to a procedure
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'neg': 'mat 1 0', # negation
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'juc': 'jmp 6 0', # direct unconditional jump
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'ige': 'jmp 10', # indirect jump if greater than or equals to zero
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'ile': 'jmp 11', # indirect jump if less than or equals to zero
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'ine': 'jmp 12', # indirect jump if not equals to zero
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'cos': 'mat 10', # cosine
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'atn': 'mat 11', # arctangent
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'jeq': 'jmp 0', # direct jump if equals to zero
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'jgt': 'jmp 1', # direct jump if greater than zero
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'jlt': 'jmp 2', # direct jump if less than zero
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'jge': 'jmp 3', # direct jump if greater than or equals to zero
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'jle': 'jmp 4', # direct jump if less than or equals to zero
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'jne': 'jmp 5', # direct jump if not equals to zero
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'ieq': 'jmp 7', # indirect jump if equals to zero
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'igt': 'jmp 8', # indirect jump if greater than zero
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'ilt': 'jmp 9', # indirect jump if less than zero
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'out': 'ino 0', # normal numeric output
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'inp': 'ino 1', # normal numeric input
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'ouc': 'ino 2', # character output
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'ipc': 'ino 3', # character input
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'dca': 'cpy 0', # direct constant assignment
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'dva': 'cpy 1', # direct value assignment
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'ica': 'cpy 2', # indirect constant assignment
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'iva': 'cpy 3', # indirect value assignment
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'ivc': 'cpy 4', # indirect value copy
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'add': 'mat 0', # addition
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'sub': 'mat 1', # subtraction
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'mul': 'mat 2', # multiplication
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'div': 'mat 3', # division
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'mdf': 'mat 4', # modulo/floor
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'abs': 'mat 5', # absolute value
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'sqr': 'mat 6', # square root
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'exp': 'mat 7', # natural exponent
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'log': 'mat 8', # natural logarithm
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'sin': 'mat 9' # sine
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}
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# converts the N8A source code to the plaintext machine code representation
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def assemble(source):
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labels = {}
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out = ''
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lno = 0
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vreg = re.compile(r'\s+')
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for shrt, meaning in jmpfunc_shorts.items(): # replace the shortcuts
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source = source.replace(shrt, meaning)
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for line in source.split('\n'): # parse the main code
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fields = []
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line = line.split(';')[0].strip()
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if len(line) > 0: # actual line to be counted on
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fields = vreg.split(line)[:5] # split it into fields
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if fields[0].startswith(':'): # this is a label
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labels[fields[0]] = lno # remember the label
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fields = fields[1:] # remove the label from fields
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elif fields[0].startswith('#'): # this is an alias
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labels['@' + fields[1].strip()] = int(fields[0][1:])
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continue # do not update the instruction number
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try:
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cmd = mnemos.index(fields[0].lower())
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except ValueError:
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try:
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cmd = int(cmd)
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except:
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print('Assembly error - unknown mnemonic at line', lno)
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sys.exit(1)
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try:
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out += ' '.join([str(cmd), fields[1], fields[2], fields[3]]) + '\n'
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except IndexError:
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print('Assembly error - not enough operands at line', lno)
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sys.exit(1)
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lno += 1 # update the instruction number
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for lbl, lineno in labels.items():
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out = out.replace(lbl, str(lineno))
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final = '' # prepare the final text
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for line in out.split('\n'):
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if len(line) > 0:
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fields = vreg.split(line)[:4] # split it into fields
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instr = int(fields[0]) * 2097152 + int(fields[1]) * 16384
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instr += int(fields[2]) * 128 + int(fields[3])
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final += str(instr) + '\n'
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return final
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# converts the plaintext machine code representation to N8A source code
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def disassemble(machcode):
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vreg = re.compile(r'\s+')
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iindex = 0
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instrs = []
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for instrnum in vreg.split(machcode):
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if len(instrnum) > 0:
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instrnum = int(instrnum)
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opcode = (instrnum >> 21) & 7
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p1 = (instrnum >> 14) & 127
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p2 = (instrnum >> 7) & 127
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p3 = instrnum & 127
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instrs.append([iindex, opcode, p1, p2, p3])
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iindex += 1
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# now, instrs contains 5-number groups
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assembly = [None for i in range(0, 128)]
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labels = {}
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for instr in instrs: # iterate over each instruction
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lno, cmd, x, y, z = instr
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try:
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mnemo = mnemos[cmd]
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except IndexError:
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print('Disassembly error - unknown opcode at line', lno)
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sys.exit(1)
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if cmd == 1: # save the label for jump instructions
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labels[z] = ':lbl_' + str(z)
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assembly[lno] = [mnemo, str(x), str(y), labels[z]]
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else:
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assembly[lno] = [mnemo, str(x), str(y), str(z)]
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out = ''
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lno = 0
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for asline in assembly:
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if lno in labels:
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out += labels[lno] + ' '
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if asline is not None:
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out += ' '.join(asline) + '\n'
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lno += 1
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for shrt, meaning in jmpfunc_shorts.items(): # replace the shortcuts
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out = out.replace(meaning, shrt)
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return out
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# converts the plaintext machine code representation to binary representation
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def tobinary(txtrep):
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instrs = [] # instruction list to store here
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vreg = re.compile(r'\s+')
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out = b''
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for instr in vreg.split(txtrep):
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if len(instr) > 0:
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instr = int(instr)
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out += struct.pack('BBB', (instr >> 16) & 255, (instr >> 8) & 255, instr & 255)
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return out
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# converts the binary machine code representation to plaintext representation
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def totext(binrep):
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out = ''
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while len(binrep) > 0:
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chunk = binrep[0:3]
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binrep = binrep[3:]
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b1, b2, b3 = struct.unpack('BBB', chunk)
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instr = (b1 << 16) | (b2 << 8) | b3
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out += str(instr) + '\n'
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return out
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# converts the N8 plaintext machine code to the TI-74 DATA statements (N74)
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def ti74data(txtrep:str, baseaddr:int=1000):
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instrs = [] # instruction list to store here
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vreg = re.compile(r'\s+')
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out = ''
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iindex = 0
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for instr in vreg.split(txtrep):
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if len(instr) > 0:
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instrs.append(str(int(instr)))
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instrs.append(str(-1)) # add the terminating instruction
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while len(instrs) > 0:
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dchunk = instrs[:7]
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instrs = instrs[7:]
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out += f'{baseaddr + iindex} DATA {','.join(dchunk)}\n'
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iindex += 1
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return out
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def main():
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if len(sys.argv) < 4:
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print("Usage: n8asm [at|ab|dt|db|t2b|b2t|t74] file outfile")
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return
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mode = sys.argv[1]
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srcfile = sys.argv[2]
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targetfile = sys.argv[3]
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srctext = ''
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inpmode = 'r'
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if mode == 'b2t' or mode == 'db':
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inpmode = 'rb'
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try:
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fd = open(srcfile, inpmode)
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srctext = fd.read()
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close(fd)
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except:
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pass
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if len(srctext) > 0:
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outmode = 'w'
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output = ''
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if mode == 'b2t': # binary-to-text
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output = totext(srctext)
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elif mode == 't2b': # text-to-binary
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output = tobinary(srctext)
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outmode = 'wb'
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elif mode == 'dt': # disassemble text
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output = disassemble(srctext)
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elif mode == 'db': # disassemble binary
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srctext = totext(srctext)
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output = disassemble(srctext)
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elif mode == 't74': # convert to TI-74 DATA statements
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output = ti74data(srctext)
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else: # assemble
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output = assemble(srctext) # default mode
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if mode == 'ab':
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output = tobinary(output)
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outmode = 'wb'
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# write the output file
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try:
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fd = open(targetfile, outmode)
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fd.write(output)
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close(fd)
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except:
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pass
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else:
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print('Nothing to process!')
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if __name__ == '__main__':
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main()
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