forked from adafruit/circuitpython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathfloat2int.py
More file actions
89 lines (79 loc) · 2.57 KB
/
Copy pathfloat2int.py
File metadata and controls
89 lines (79 loc) · 2.57 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
# check cases converting float to int, relying only on single precision float
try:
import ustruct as struct
except:
import struct
# work out configuration values
is_64bit = struct.calcsize("P") == 8
# 0 = none, 1 = long long, 2 = mpz
try:
dummy = 0x7fffffffffffffff
try:
if (0xffffffffffffffff + 1) > 0:
ll_type = 2
else:
ll_type = 1
except:
# in case the sum in the if statement above changes to raising an exception on overflow
ll_type = 1
except:
ll_type = 0
# basic conversion
print(int(14187745.))
print("%d" % 14187745.)
if ll_type == 2:
print(int(2.**100))
print("%d" % 2.**100)
testpass = True
p2_rng = ((30,63,127),(62,63,127))[is_64bit][ll_type]
for i in range(0,p2_rng):
bitcnt = len(bin(int(2.**i))) - 3;
if i != bitcnt:
print('fail: 2**%u was %u bits long' % (i, bitcnt));
testpass = False
print("power of 2 test: %s" % (testpass and 'passed' or 'failed'))
# TODO why does 10**12 fail this test for single precision float?
testpass = True
p10_rng = 9 if (ll_type == 0 and ~is_64bit) else 11
for i in range(0,p10_rng):
digcnt = len(str(int(10.**i))) - 1;
if i != digcnt:
print('fail: 10**%u was %u digits long' % (i, digcnt));
testpass = False
print("power of 10 test: %s" % (testpass and 'passed' or 'failed'))
def fp2int_test(num, name, should_fail):
try:
x = int(num)
passed = ~should_fail
except:
passed = should_fail
print('%s: %s' % (name, passed and 'passed' or 'failed'))
if ll_type != 2:
if ll_type == 0:
if is_64bit:
neg_bad_fp = -1.00000005*2.**62.
pos_bad_fp = 2.**62.
neg_good_fp = -2.**62.
pos_good_fp = 0.99999993*2.**62.
else:
neg_bad_fp = -1.00000005*2.**30.
pos_bad_fp = 2.**30.
neg_good_fp = -2.**30.
pos_good_fp = 0.9999999499*2.**30.
else:
neg_bad_fp = -0.51*2.**64.
pos_bad_fp = 2.**63.
neg_good_fp = -2.**63.
pos_good_fp = 1.9999998*2.**62.
fp2int_test(neg_bad_fp, 'neg bad', True)
fp2int_test(pos_bad_fp, 'pos bad', True)
fp2int_test(neg_good_fp, 'neg good', False)
fp2int_test(pos_good_fp, 'pos good', False)
else:
fp2int_test(-1.999999879*2.**127., 'large neg', False)
fp2int_test(1.999999879*2.**127., 'large pos', False)
fp2int_test(float('inf'), 'inf test', True)
fp2int_test(float('nan'), 'NaN test', True)
# test numbers < 1 (this used to fail; see issue #1044)
fp2int_test(0.0001, 'small num', False)
struct.pack('I', int(1/2))