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author | Kevin B Kenny <kennykb@acm.org> | 2005-01-19 22:41:26 (GMT) |
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committer | Kevin B Kenny <kennykb@acm.org> | 2005-01-19 22:41:26 (GMT) |
commit | b9cf65a08e6a59e434685e894e3189c201ac6791 (patch) | |
tree | 1f0868ef44c9f17d83d10dc94343df7b8cfe1842 /libtommath/bn_mp_get_int.c | |
parent | c6a259aeeca4814a97cf6694814c63e74e4e18fa (diff) | |
download | tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.zip tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.tar.gz tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.tar.bz2 |
Import of libtommath 0.33
Diffstat (limited to 'libtommath/bn_mp_get_int.c')
-rw-r--r-- | libtommath/bn_mp_get_int.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/libtommath/bn_mp_get_int.c b/libtommath/bn_mp_get_int.c new file mode 100644 index 0000000..034467b --- /dev/null +++ b/libtommath/bn_mp_get_int.c @@ -0,0 +1,41 @@ +#include <tommath.h> +#ifdef BN_MP_GET_INT_C +/* LibTomMath, multiple-precision integer library -- Tom St Denis + * + * LibTomMath is a library that provides multiple-precision + * integer arithmetic as well as number theoretic functionality. + * + * The library was designed directly after the MPI library by + * Michael Fromberger but has been written from scratch with + * additional optimizations in place. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org + */ + +/* get the lower 32-bits of an mp_int */ +unsigned long mp_get_int(mp_int * a) +{ + int i; + unsigned long res; + + if (a->used == 0) { + return 0; + } + + /* get number of digits of the lsb we have to read */ + i = MIN(a->used,(int)((sizeof(unsigned long)*CHAR_BIT+DIGIT_BIT-1)/DIGIT_BIT))-1; + + /* get most significant digit of result */ + res = DIGIT(a,i); + + while (--i >= 0) { + res = (res << DIGIT_BIT) | DIGIT(a,i); + } + + /* force result to 32-bits always so it is consistent on non 32-bit platforms */ + return res & 0xFFFFFFFFUL; +} +#endif |