clamav/libclamav/tomsfastmath/exptmod/fp_2expt.c
Micah Snyder 375ecf678c Update vendored TomsFastMath code to 0.13.1
Update the vendored TomsFastMath (TFM) library to v0.13.1.

Resolves: https://bugzilla.clamav.net/show_bug.cgi?id=11992

I removed compatibility macro's from when libTomMath was used.
This required removing a bunch of faux-error handling because
the fast-math equivalent functions return void, and cannot fail.

The previous version used had named the header "bignum_fast.h"
instead of "tfm.h" and had customizations in that header to enable
TFM_CHECK all the time, and also TFM_NO_ASM if __GNUC__ not defined
or if the system isn't 64bit architecture. This update uses tfm.h
as-is, and has CMake define TFM_CHECK and TFM_NO_ASM as needed.

I've kept bignum.h as an interface to including tfm.h so that in
the future we can more easily add support for system-installed
TomsFastMath instead of the vendored one, taking inspiration from
Debian's patch to support system-TomsFastMath.

See: https://salsa.debian.org/clamav-team/clamav/-/blob/unstable/debian/patches/add-support-for-system-tomsfastmath.patch
2022-02-10 12:54:23 -07:00

39 lines
705 B
C

/* TomsFastMath, a fast ISO C bignum library.
*
* This project is meant to fill in where LibTomMath
* falls short. That is speed ;-)
*
* This project is public domain and free for all purposes.
*
* Tom St Denis, tomstdenis@gmail.com
*/
#include <tfm_private.h>
/* computes a = 2**b */
void fp_2expt(fp_int *a, int b)
{
int z;
/* zero a as per default */
fp_zero (a);
if (b < 0) {
return;
}
z = b / DIGIT_BIT;
if (z >= FP_SIZE) {
return;
}
/* set the used count of where the bit will go */
a->used = z + 1;
/* put the single bit in its place */
a->dp[z] = ((fp_digit)1) << (b % DIGIT_BIT);
}
/* $Source$ */
/* $Revision$ */
/* $Date$ */