blob: 635000d2672c01f3fed0ffbe0550969f5ec36733 (
plain) (
blame)
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
|
/* See LICENSE file for copyright and license details. */
#include "common.h"
enum libsyscalls_error
libsyscalls_parse_signed_integer(unsigned long long int value_in,
enum libsyscalls_datatype_sign_representation representation,
size_t bits, unsigned long long int *value_out, int *negative_out)
{
unsigned long long int value = value_in, mask;
int negative = 0;
if (!bits || bits > sizeof(value) / sizeof(char) * CHAR_BIT)
return LIBSYSCALLS_E_INVAL;
switch (representation) {
case LIBSYSCALLS_SIGN_UNDETERMINED:
break;
case LIBSYSCALLS_SIGN_TWOS_COMPLEMENT:
if (value >> (bits - 1U)) {
mask = (1ULL << (bits - 1U)) - 1ULL;
value = ~value & mask;
value += 1ULL;
negative = 1;
}
break;
case LIBSYSCALLS_SIGN_ONES_COMPLEMENT:
if (value >> (bits - 1U)) {
mask = (1ULL << (bits - 1U)) - 1ULL;
value = ~value & mask;
negative = 1;
}
break;
case LIBSYSCALLS_SIGN_SIGN_MAGNITUDE:
if (value >> (bits - 1U)) {
value ^= 1ULL << (bits - 1U);
negative = 1;
}
break;
case LIBSYSCALLS_SIGN_EXCESS_HALF:
if (value >> (bits - 1U)) {
value ^= 1ULL << (bits - 1U);
} else {
value = (1ULL << (bits - 1U)) - value;
negative = 1;
}
break;
default:
return LIBSYSCALLS_E_INVAL;
}
if (value_out)
*value_out = value;
if (negative_out)
*negative_out = negative;
return LIBSYSCALLS_E_OK;
}
|
