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comparison python/libasm.py @ 159:5e1dd04cb61c

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Added attempt to assembler
author Windel Bouwman
date Fri, 08 Mar 2013 17:16:22 +0100
parents
children 6b2bec5653f1
comparison
equal deleted inserted replaced
158:9683a4cd848f 159:5e1dd04cb61c
1 import collections, re
2
3 # Different instruction sets:
4 class InstructionSet:
5 pass
6
7 class X86(InstructionSet):
8 pass
9
10 # Generic assembler:
11
12 class SourceLocation:
13 def __init__(self, x):
14 self.pos = x
15
16 class SourceRange:
17 def __init__(self, p1, p2):
18 self.p1 = p1
19 self.p2 = p2
20
21 # Token is used in the lexical analyzer:
22 Token = collections.namedtuple('Token', 'typ val row col')
23
24 keywords = ['global', 'db']
25
26 def tokenize(s):
27 """
28 Tokenizer, generates an iterator that
29 returns tokens!
30
31 This GREAT example was taken from python re doc page!
32 """
33 tok_spec = [
34 ('REAL', r'\d+\.\d+'),
35 ('HEXNUMBER', r'0x[\da-fA-F]+'),
36 ('NUMBER', r'\d+'),
37 ('ID', r'[A-Za-z][A-Za-z\d_]*'),
38 ('NEWLINE', r'\n'),
39 ('SKIP', r'[ \t]'),
40 ('LEESTEKEN', r':=|[\.,=:;\-+*\[\]/\(\)]|>=|<=|<>|>|<'),
41 ('STRING', r"'.*?'")
42 ]
43 tok_re = '|'.join('(?P<%s>%s)' % pair for pair in tok_spec)
44 print(tok_re)
45 gettok = re.compile(tok_re).match
46 line = 1
47 pos = line_start = 0
48 mo = gettok(s)
49 while mo is not None:
50 typ = mo.lastgroup
51 val = mo.group(typ)
52 if typ == 'NEWLINE':
53 line_start = pos
54 line += 1
55 elif typ == 'COMMENTS':
56 pass
57 elif typ != 'SKIP':
58 if typ == 'ID':
59 if val in keywords:
60 typ = val
61 elif typ == 'LEESTEKEN':
62 typ = val
63 elif typ == 'NUMBER':
64 val = int(val)
65 elif typ == 'HEXNUMBER':
66 val = int(val[2:], 16)
67 typ = 'NUMBER'
68 elif typ == 'REAL':
69 val = float(val)
70 elif typ == 'STRING':
71 val = val[1:-1]
72 yield Token(typ, val, line, mo.start()-line_start)
73 pos = mo.end()
74 mo = gettok(s, pos)
75 if pos != len(s):
76 col = pos - line_start
77 raise CompilerException('Unexpected character {0}'.format(s[pos]), line, col)
78 yield Token('END', '', line, 0)
79
80 class Lexer:
81 def __init__(self, src):
82 self.tokens = tokenize(src)
83 self.curTok = self.tokens.__next__()
84 def eat(self):
85 t = self.curTok
86 self.curTok = self.tokens.__next__()
87 return t
88 @property
89 def Peak(self):
90 return self.curTok
91
92 class Parser:
93 def __init__(self, lxr):
94 self.lxr = lxr
95 def parse(self):
96 t = self.lxr.eat()
97
98 while True:
99 ins = self.parseLine()
100 print(ins)
101 t = self.lxr.eat()
102 def parseLine(self):
103 self.parseLabel()
104 if self.lxr.Peak == ';':
105 self.eatComments()
106 def parseLabel(self):
107 i = self.lxr.eat()
108
109 class Assembler:
110 def assemble(self, asmsrc):
111 print('assembling', asmsrc)
112 lxr = Lexer(asmsrc)
113 prsr = Parser(lxr)
114 instructions = prsr.parse()
115 return instructions
116