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comparison python/ppci/target/token.py @ 342:86b02c98a717 devel

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Moved target directory
author Windel Bouwman
date Sat, 01 Mar 2014 15:40:31 +0100
parents
children 988f3fb861e4
comparison
equal deleted inserted replaced
341:4d204f6f7d4e 342:86b02c98a717
1
2 import struct
3
4 def u16(h):
5 return struct.pack('<H', h)
6
7
8 def u32(x):
9 return struct.pack('<I', x)
10
11
12 def val2bit(v, bits):
13 b = []
14 for i in range(bits):
15 b.append(bool((1<<i) & v))
16 #b.reverse()
17 return b
18
19
20 def bit_range(b, e):
21 """ Property generator function """
22 getter = lambda s: s[b:e]
23 def setter(s, v):
24 s[b:e] = v
25 return property(getter, setter)
26
27
28 class Token:
29 def __init__(self, bitsize):
30 self.bitsize = bitsize
31 self.bit_value = 0
32
33 def set_bit(self, i, value):
34 value = bool(value)
35 assert i in range(0, self.bitsize)
36 mask = 1 << i
37 if value:
38 self.bit_value |= mask
39 else:
40 self.bit_value &= (~mask)
41
42 def __getitem__(self, key):
43 return False
44
45 def __setitem__(self, key, value):
46 if type(key) is int:
47 self.set_bit(key, value)
48 elif type(key) is slice:
49 assert key.step is None
50 bits = key.stop - key.start
51 value_bits = val2bit(value, bits)
52 for i in range(key.start, key.stop):
53 self.set_bit(i, value_bits[i - key.start])
54 else:
55 raise KeyError()
56