miscellaneous functions, not necessarily related to canonical forms. More...

#include "globaldefs.h"
#include "config.h"
#include "cf_util.h"
#include <stdio.h>
#include <stdlib.h>

Functions
int	ipower (int b, int m)
	int ipower ( int b, int m ) More...

int	ilog2 (int v)

int	igcd (int a, int b)

void	factoryError_intern (const char *s)

Variables
VAR void(*	factoryError )(const char *s) = factoryError_intern

Detailed Description

miscellaneous functions, not necessarily related to canonical forms.

Used by: fac_cantzass.cc, gfops.cc

Definition in file cf_util.cc.

Function Documentation

◆ factoryError_intern()

void factoryError_intern ( const char * s )

Definition at line 75 of file cf_util.cc.

{
  fputs(s,stderr);
  abort();
}

◆ igcd()

int igcd	(	int	a,
		int	b
	)

Definition at line 56 of file cf_util.cc.

{
    if ( a < 0 ) a = -a;
    if ( b < 0 ) b = -b;
 
    int c;
 
    while ( b != 0 )
    {
        c = a % b;
        a = b;
        b = c;
    }
    return a;
}

◆ ilog2()

int ilog2 ( int v )

Definition at line 42 of file cf_util.cc.

{
  const unsigned int b[] = {0x2, 0xC, 0xF0, 0xFF00, 0xFFFF0000};
  const unsigned int S[] = {1, 2, 4, 8, 16};
 
  unsigned int r = 0; // result of log2(v) will go here
  if (v & b[4]) { v >>= S[4]; r |= S[4]; }
  if (v & b[3]) { v >>= S[3]; r |= S[3]; }
  if (v & b[2]) { v >>= S[2]; r |= S[2]; }
  if (v & b[1]) { v >>= S[1]; r |= S[1]; }
  if (v & b[0]) { v >>= S[0]; r |= S[0]; }
  return (int)r;
}

◆ ipower()

int ipower	(	int	b,
		int	m
	)

int ipower ( int b, int m )

ipower() - calculate b^m in standard integer arithmetic.

Note: Beware of overflows.

Definition at line 27 of file cf_util.cc.

{
    int prod = 1;
 
    while ( m != 0 )
    {
        if ( m % 2 != 0 )
            prod *= b;
        m /= 2;
        if ( m != 0 )
            b *= b;
    }
    return prod;
}

Variable Documentation

◆ factoryError

VAR void(* factoryError) (const char *s) ( const char * s ) = factoryError_intern

Definition at line 80 of file cf_util.cc.

Functions

Variables