def fn_ds(tokenizer, phaseNumber):
global gLoc
value = eval.Expression(tokenizer).eval()
if value == None:
raise Exception("Undefined expression")
gLoc += value
def fn_dw(tokenizer, phaseNumber):
while not tokenizer.atEnd():
if tokenizer.curTok() == tok.STRING:
s = tokenizer.curValue()
for c in s:
depositWord(ord(c))
tokenizer.advance()
else:
expr = eval.Expression(tokenizer)
value = expr.eval()
if phaseNumber > 0:
depositWord(value)
else:
depositWord(0)
if tokenizer.curTok() != ',':
break
else:
tokenizer.advance()
def fn_db(tokenizer, phaseNumber):
while not tokenizer.atEnd():
if tokenizer.curTok() == tok.STRING:
s = tokenizer.curValue()
for c in s:
depositByte(ord(c))
tokenizer.advance()
else:
expr = eval.Expression(tokenizer)
value = expr.eval()
if phaseNumber > 0:
if value > 0xff or value < -128:
raise Exception("value too large for a byte")
depositByte(value)
else:
depositByte(0)
if tokenizer.curTok() != ',':
break
else:
tokenizer.advance()
def assembleLine(line, phaseNumber=0):
global gLoc
for k, v in gDefines.items():
line = line.replace(k, v)
clearLineBytes()
tokenizer = tok.Tokenizer(line)
#
# Set '*' psuedo-symbol at the start of each line
#
symbols.set('*', gLoc)
#
# SYMBOL = VALUE
#
if tokenizer.curTok() == tok.SYMBOL and tokenizer.peek(1) == '=':
sym = tokenizer.curValue()
tokenizer.advance(2)
expr = eval.Expression(tokenizer)
if not tokenizer.atEnd():
raise Exception("Bad expression (extra gunk)")
value = expr.eval()
if phaseNumber > 0 and value == None:
raise Exception(str.format("Undefined expression"))
symbols.set(sym, expr.eval())
if gListingFile != None and phaseNumber > 0:
generateListingLine(line)
return
#
# handle SYMBOL: at start of line
# NOTE: could enforce leadingWhitespace, but we have a ':'
# instead of that.
#
if tokenizer.curTok() == tok.SYMBOL and tokenizer.peek(1) == ':':
sym = tokenizer.curValue()
tokenizer.advance(2)
if phaseNumber == 0:
symbols.set(sym, gLoc)
else:
#
# check that the symbol has the same value in
# subsequent phases
#
symbols.setScope(sym)
if symbols.get(sym) != gLoc:
raise Exception(
str.format("Symbol phase error (expected {0}, have {1})",
symbols.get(sym), gLoc))
#
# handle ops
#
if tokenizer.curTok() == tok.SYMBOL:
op = tokenizer.curValue().lower()
tokenizer.advance()
if op in gPsuedoOps:
gPsuedoOps[op](tokenizer, phaseNumber)
elif op in preOps:
if preOps[op](line):
raise Exception("define syntax error")
elif op in gOps:
assembleInstruction(op, tokenizer, phaseNumber)
else:
raise Exception(str.format('Unknown op: {0}', op))
if gListingFile != None and phaseNumber > 0:
generateListingLine(line)
def parseAddressingMode(tokenizer):
if tokenizer.atEnd():
return IMPLIED, None
if tokenizer.curTok() == '#':
tokenizer.advance()
expr = eval.Expression(tokenizer)
return IMMED, expr
#
# (n)
# (nn)
# (n,x)
# (n),y
#
if tokenizer.curTok() == '(':
tokenizer.advance()
expr = eval.Expression(tokenizer)
# (expr,x)
if tokenizer.curTok() == ',':
if tokenizer.peek(1) == tok.SYMBOL and tokenizer.peekValue(
1).lower() == 'x' and tokenizer.peek(2) == ')':
tokenizer.advance(3)
return INDX, expr
else:
raise Exception(
"bad addressing mode (started out looking like indirect-x)"
)
elif tokenizer.curTok() == ')':
tokenizer.advance()
#
# (expr),y
# (expr)
#
if tokenizer.curTok() == ',' and tokenizer.peek(
1) == tok.SYMBOL and tokenizer.peekValue(1).lower() == 'y':
tokenizer.advance(2)
return INDY, expr
else:
return IND, expr
else:
raise Exception(
"bad addressing mode (started out looking indirect, but fizzled)"
)
#
# nn
# n
# rel
#
# n,x
# n,y
#
expr = eval.Expression(tokenizer)
if tokenizer.curTok() == ',':
tokenizer.advance()
if tokenizer.curTok() == tok.SYMBOL:
if tokenizer.curValue().lower() == 'x':
return UNDECIDED_X, expr
elif tokenizer.curValue().lower() == 'y':
return UNDECIDED_Y, expr
else:
raise Exception(
str.format("Unxpected symbol {0} following expression",
tokenizer.curValue()))
else:
raise Exception("Unxpected gunk following expression")
return UNDECIDED, expr
def fn_org(tokenizer, phaseNumber):
global gLoc
org = eval.Expression(tokenizer).eval()
if org == None:
raise Exception("Undefined expression")
gLoc = org