fp_lshd.c

00001 /* TomsFastMath, a fast ISO C bignum library.
00002  * 
00003  * This project is meant to fill in where LibTomMath
00004  * falls short.  That is speed ;-)
00005  *
00006  * This project is public domain and free for all purposes.
00007  * 
00008  * Tom St Denis, tomstdenis@gmail.com
00009  */
00010 #include <tfm.h>
00011 
00012 void fp_lshd(fp_int *a, int x)
00013 {
00014    int y;
00015 
00016    /* move up and truncate as required */
00017    y = MIN(a->used + x - 1, (int)(FP_SIZE-1));
00018 
00019    /* store new size */
00020    a->used = y + 1;
00021 
00022    /* move digits */
00023    for (; y >= x; y--) {
00024        a->dp[y] = a->dp[y-x];
00025    }
00026  
00027    /* zero lower digits */
00028    for (; y >= 0; y--) {
00029        a->dp[y] = 0;
00030    }
00031 
00032    /* clamp digits */
00033    fp_clamp(a);
00034 }
00035 
00036 /* $Source: /cvs/libtom/tomsfastmath/src/bit/fp_lshd.c,v $ */
00037 /* $Revision: 1.1 $ */
00038 /* $Date: 2006/12/31 21:25:53 $ */