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
|
/* _PDCLIB_bigint_mul32( _PDCLIB_bigint_t *, uint_least32_t )
This file is part of the Public Domain C Library (PDCLib).
Permission is granted to use, modify, and / or redistribute at will.
*/
#ifndef REGTEST
#include "pdclib/_PDCLIB_internal.h"
#include <stdint.h>
_PDCLIB_bigint_t * _PDCLIB_bigint_mul32( _PDCLIB_bigint_t * _PDCLIB_restrict lhs, uint_least32_t rhs )
{
uint_least64_t digit; /* Hold intermediary (wide) result. */
uint_least32_t carry = 0; /* Hold overflow. */
int i;
for ( i = 0; i < lhs->size; ++i )
{
/* Add product and carry into intermediate result */
digit = (uint_least64_t)lhs->data[ i ] * (uint_least64_t)rhs + carry;
/* Get 32bit carry */
carry = digit >> 32;
/* Write lower 32bit back into bigint */
lhs->data[ i ] = ( digit & UINT32_C( 0xFFFFFFFF ) );
}
if ( carry > 0 )
{
lhs->data[ lhs->size++ ] = carry;
}
return lhs;
}
#endif
#ifdef TEST
#include "_PDCLIB_test.h"
int main( void )
{
#ifndef REGTEST
_PDCLIB_bigint_t lhs;
_PDCLIB_bigint32( &lhs, 0 );
_PDCLIB_bigint_mul32( &lhs, 0 );
TESTCASE( lhs.size == 0 );
_PDCLIB_bigint_mul32( &lhs, 1 );
TESTCASE( lhs.size == 0 );
_PDCLIB_bigint32( &lhs, 2 );
_PDCLIB_bigint_mul32( &lhs, 1 );
TESTCASE( lhs.size == 1 );
TESTCASE( lhs.data[0] == 2 );
_PDCLIB_bigint64( &lhs, UINT64_C( 0x100000000 ) );
_PDCLIB_bigint_mul32( &lhs, 2 );
TESTCASE( lhs.size == 2 );
TESTCASE( lhs.data[0] == 0 );
TESTCASE( lhs.data[1] == 2 );
_PDCLIB_bigint_mul32( &lhs, UINT32_C( 0x80000000 ) );
TESTCASE( lhs.size == 3 );
TESTCASE( lhs.data[0] == 0 );
TESTCASE( lhs.data[1] == 0 );
TESTCASE( lhs.data[2] == 1 );
#endif
return TEST_RESULTS;
}
#endif
|
