rt_gccstream/gcc/ada/arit64.c

58 lines
3.3 KiB
C

/****************************************************************************
* *
* GNAT COMPILER COMPONENTS *
* *
* A R I T 6 4 . C *
* *
* C Implementation File *
* *
* Copyright (C) 2009, Free Software Foundation, Inc. *
* *
* GNAT is free software; you can redistribute it and/or modify it under *
* terms of the GNU General Public License as published by the Free Soft- *
* ware Foundation; either version 3, or (at your option) any later ver- *
* sion. GNAT is distributed in the hope that it will be useful, but WITH- *
* OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
* or FITNESS FOR A PARTICULAR PURPOSE. *
* *
* As a special exception under Section 7 of GPL version 3, you are granted *
* additional permissions described in the GCC Runtime Library Exception, *
* version 3.1, as published by the Free Software Foundation. *
* *
* You should have received a copy of the GNU General Public License and *
* a copy of the GCC Runtime Library Exception along with this program; *
* see the files COPYING3 and COPYING.RUNTIME respectively. If not, see *
* <http://www.gnu.org/licenses/>. *
* *
* GNAT was originally developed by the GNAT team at New York University. *
* Extensive contributions were provided by Ada Core Technologies Inc. *
* *
****************************************************************************/
extern void __gnat_rcheck_10(char *file, int line)
__attribute__ ((__noreturn__));
long long int __gnat_mulv64 (long long int x, long long int y)
{
unsigned neg = (x >= 0) ^ (y >= 0);
long long unsigned xa = x >= 0 ? (long long unsigned) x
: -(long long unsigned) x;
long long unsigned ya = y >= 0 ? (long long unsigned) y
: -(long long unsigned) y;
unsigned xhi = (unsigned) (xa >> 32);
unsigned yhi = (unsigned) (ya >> 32);
unsigned xlo = (unsigned) xa;
unsigned ylo = (unsigned) ya;
long long unsigned mid
= xhi ? (long long unsigned) xhi * (long long unsigned) ylo
: (long long unsigned) yhi * (long long unsigned) xlo;
long long unsigned low = (long long unsigned) xlo * (long long unsigned) ylo;
if ((xhi && yhi) || mid + (low >> 32) > 0x7fffffff + neg)
__gnat_rcheck_10 (__FILE__, __LINE__);
low += ((long long unsigned) (unsigned) mid) << 32;
return (long long int) (neg ? -low : low);
}