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mu808/mu808asm.py
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Python
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#!/usr/bin/env python3
# a simple assembler/disassembler for the mu808 VM
# supports both text and binary program formats
# usage: mu808asm [at|ab|dt|db|t2b|b2t|t74] file outfile
# modes:
# at: assemble to plaintext (MU8) machine code
# ab: assemble to binary (MU8B) machine code
# dt: disassemble plaintext (MU8) machine code
# db: disassemble binary (MU8B) machine code
# t2b: convert from plaintext MU8 to binary MU8B
# b2t: convert from binary MU8B to plaintext MU8
# t74: convert from plaintext MU8 to the TI-74 representation
import sys, re, struct
# mu808 mnemonics for assembly and disasssembly
mnemos = ['nop', 'jmp', 'iat', 'out', 'inp', 'set', 'cpy', 'fma',
'sub', 'div', 'mdf', 'abs', 'sqr', 'nel', 'tri', 'rnd']
# mu808 jump/function shortcuts
jmpfunc_shorts = {
'jeq': 'jmp 0', # direct jump if equals to zero
'jgt': 'jmp 1', # direct jump if greater than zero
'jlt': 'jmp 2', # direct jump if less than zero
'jge': 'jmp 3', # direct jump if greater than or equals to zero
'jle': 'jmp 4', # direct jump if less than or equals to zero
'jne': 'jmp 5', # direct jump if not equals to zero
'juc': 'jmp 6 0', # direct unconditional jump
'ieq': 'jmp 7', # indirect jump if equals to zero
'igt': 'jmp 8', # indirect jump if greater than zero
'ilt': 'jmp 9', # indirect jump if less than zero
'ige': 'jmp 10', # indirect jump if greater than or equals to zero
'ile': 'jmp 11', # indirect jump if less than or equals to zero
'ine': 'jmp 12', # indirect jump if not equals to zero
'iuc': 'jmp 13 0', # indirect unconditional jump
'dia': 'cpy 0', # direct integer assignment
'dva': 'cpy 1', # direct value assignment
'iva': 'cpy 2', # indirect value assignment
'exp': 'nel 0', # natural exponent
'log': 'nel 1', # natural logarithm
'sin': 'tri 0', # sine
'cos': 'tri 1', # cosine
'atn': 'tri 2' # arctangent
}
# converts the MU8A source code to the plaintext machine code representation
def assemble(source):
labels = {}
out = ''
lno = 0
vreg = re.compile(r'\s+')
for shrt, meaning in jmpfunc_shorts.items(): # replace the shortcuts
source = source.replace(shrt, meaning)
for line in source.split('\n'): # parse the main code
fields = []
line = line.split(';')[0].strip()
if len(line) > 0: # actual line to be counted on
lno += 1 # populate the line number
fields = vreg.split(line)[:5] # split it into fields
if fields[0].startswith(':'): # this is a label
labels[fields[0]] = lno # remember the label
fields = fields[1:] # remove the label from fields
try:
cmd = mnemos.index(fields[0].lower())
except ValueError:
try:
cmd = int(cmd)
except:
print('Assembly error - unknown mnemonic at line', lno)
sys.exit(1)
try:
out += ' '.join([str(lno), str(cmd), fields[1], fields[2], fields[3]]) + '\n'
except IndexError:
print('Assembly error - not enough operands at line', lno)
sys.exit(1)
for lbl, lineno in labels.items():
out = out.replace(lbl, str(lineno))
return out
# converts the plaintext machine code representation to MU8A source code
def disassemble(machcode):
vreg = re.compile(r'\s+')
iindex = 0
instr = []
instrs = []
for instrpart in vreg.split(machcode):
if iindex == 5:
instrs.append(instr)
instr = []
iindex = 0
if len(instrpart) > 0:
instr.append(int(instrpart))
iindex += 1
# now, instrs contains 5-number groups
assembly = [None for i in range(0, 16384)]
labels = {}
for instr in instrs: # iterate over each instruction
lno, cmd, x, y, z = instr
try:
mnemo = mnemos[cmd]
except IndexError:
print('Disassembly error - unknown opcode at line', lno)
sys.exit(1)
if cmd == 1: # save the label for jump instructions
labels[z] = ':lbl_' + str(z)
assembly[lno] = [mnemo, str(x), str(y), labels[z]]
else:
assembly[lno] = [mnemo, str(x), str(y), str(z)]
out = ''
lno = 0
for asline in assembly:
if lno in labels:
out += labels[lno] + ' '
if asline is not None:
out += ' '.join(asline) + '\n'
lno += 1
for shrt, meaning in jmpfunc_shorts.items(): # replace the shortcuts
out = out.replace(meaning, shrt)
return out
# converts the plaintext machine code representation to binary representation
def tobinary(txtrep):
instrs = [] # instruction list to store here
vreg = re.compile(r'\s+')
iindex = 0
instr = []
for instrpart in vreg.split(txtrep):
if iindex == 5:
instrs.append(instr)
instr = []
iindex = 0
if len(instrpart) > 0:
instr.append(int(instrpart))
iindex += 1
# now, instrs contains 5-number groups
out = b''
# the format is: cmd (8 bits), lno (14 bits), arg1 to arg3 (14 bits each)
for instr in instrs: # iterate over each instruction
b1 = instr[1] & 15
b2 = (instr[0] >> 6) & 255
b3 = ((instr[0] << 2) | (instr[2] >> 12)) & 255
b4 = (instr[2] >> 4) & 255
b5 = ((instr[2] << 4) | (instr[3] >> 10)) & 255
b6 = (instr[3] >> 2) & 255
b7 = ((instr[3] << 6) | (instr[4] >> 8)) & 255
b8 = instr[4] & 255
out += struct.pack('BBBBBBBB', b1, b2, b3, b4, b5, b6, b7, b8)
return out
# converts the binary machine code representation to plaintext representation
def totext(binrep):
out = ''
while len(binrep) > 0:
chunk = binrep[0:8]
binrep = binrep[8:]
b1, b2, b3, b4, b5, b6, b7, b8 = struct.unpack('BBBBBBBB', chunk)
cmd = b1 & 15
lno = ((b2 << 6) | (b3 >> 2)) & 16383
x = ((b3 << 12) | (b4 << 4) | (b5 >> 4)) & 16383
y = ((b5 << 10) | (b6 << 2) | (b7 >> 6)) & 16383
z = ((b7 << 8) | b8) & 16383
out += ' '.join([str(lno), str(cmd), str(x), str(y), str(z)]) + '\n'
return out
# converts the MU8 plaintext machine code to the TI-74 DATA statements (MU74)
def ti74data(txtrep:str, baseaddr:int=5000):
instrs = [] # instruction list to store here
vreg = re.compile(r'\s+')
iindex = 0
instr = []
for instrpart in vreg.split(txtrep):
if iindex == 5:
instrs.append(instr)
instr = []
iindex = 0
if len(instrpart) > 0:
instr.append(int(instrpart))
iindex += 1
# now, instrs contains 5-number groups
out = f'{baseaddr} DATA 0,0\n'
maxlno = 0
for instr in instrs:
lno, cmd, x, y, z = instr
if lno > maxlno:
maxlno = lno
a = cmd*10000 + x
b = y*10000 + z
out += f'{baseaddr + lno} DATA {a},{b}\n'
out += f'{baseaddr + maxlno + 1} DATA -1,0\n'
return out
def main():
if len(sys.argv) < 4:
print("Usage: mu808asm [at|ab|dt|db|t2b|b2t|t74] file outfile")
return
mode = sys.argv[1]
srcfile = sys.argv[2]
targetfile = sys.argv[3]
srctext = ''
inpmode = 'r'
if mode == 'b2t' or mode == 'db':
inpmode = 'rb'
try:
fd = open(srcfile, inpmode)
srctext = fd.read()
close(fd)
except:
pass
if len(srctext) > 0:
outmode = 'w'
output = ''
if mode == 'b2t': # binary-to-text
output = totext(srctext)
elif mode == 't2b': # text-to-binary
output = tobinary(srctext)
outmode = 'wb'
elif mode == 'dt': # disassemble text
output = disassemble(srctext)
elif mode == 'db': # disassemble binary
srctext = totext(srctext)
output = disassemble(srctext)
elif mode == 't74': # convert to TI-74 DATA statements
output = ti74data(srctext)
else: # assemble
output = assemble(srctext) # default mode
if mode == 'ab':
output = tobinary(output)
outmode = 'wb'
# write the output file
try:
fd = open(targetfile, outmode)
fd.write(output)
close(fd)
except:
pass
else:
print('Nothing to process!')
if __name__ == '__main__':
main()