source: libcfa/src/math.cfa @ 71f3d45

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// math.cpp --
//
// Author           : Andrew Beach
// Created On       : Mon Nov 25 16:20:00 2024
// Last Modified By : Andrew Beach
// Created On       : Mon Nov 27 15:11:00 2024
// Update Count     : 0
//

#include "math.hfa"

#include <limits.h>

#pragma GCC visibility push(default)

// Implementation of power functions (from the prelude):

#define __CFA_EXP__() \
        if ( y == 0 ) return 1;                             /* convention */ \
        __CFA_EXP_INT__(                                    /* special cases for integral types */ \
                if ( x == 1 ) return 1;                         /* base case */ \
                if ( x == 2 ) return x << (y - 1);              /* positive shifting */ \
                if ( y >= sizeof(y) * CHAR_BIT ) return 0;      /* immediate overflow, negative exponent > 2^size-1 */ \
        ) \
        typeof(x) op = 1;                                   /* accumulate odd product */ \
        typeof(x) w = x; /* FIX-ME: possible bug in the box pass changing value argument through parameter */ \
        for ( ; y > 1; y >>= 1 ) {                          /* squaring exponentiation, O(log2 y) */ \
                if ( (y & 1) == 1 ) op = op * w;                /* odd ? */ \
                w = w * w; \
        } \
        return w * op
#define __CFA_EXP_INT__(...) __VA_ARGS__

int ?\?( int x, unsigned int y ) { __CFA_EXP__(); }
long int ?\?( long int x, unsigned long int y ) { __CFA_EXP__(); }
long long int ?\?( long long int x, unsigned long long int y ) { __CFA_EXP__(); }
unsigned int ?\?( unsigned int x, unsigned int y ) { __CFA_EXP__(); }
unsigned long int ?\?( unsigned long int x, unsigned long int y ) { __CFA_EXP__(); }
unsigned long long int ?\?( unsigned long long int x, unsigned long long int y ) { __CFA_EXP__(); }

#undef __CFA_EXP_INT__
#define __CFA_EXP_INT__(...)

forall( OT | { void ?{}( OT & this, one_t ); OT ?*?( OT, OT ); } ) {
        OT ?\?( OT x, unsigned int y ) { __CFA_EXP__(); }
        OT ?\?( OT x, unsigned long int y ) { __CFA_EXP__(); }
        OT ?\?( OT x, unsigned long long int y ) { __CFA_EXP__(); }
} // distribution

#undef __CFA_EXP_INT__
#undef __CFA_EXP__