ref: 7c76dac1b268038f567939a70a18228e790a5cbc
dir: /double.c/
/*******************************************************************
** m a t h 6 4 . c
** Forth Inspired Command Language - 64 bit math support routines
** Authors: Michael A. Gauland (gaulandm@mdhost.cse.tek.com)
** Larry Hastings (larry@hastings.org)
** John Sadler (john_sadler@alum.mit.edu)
** Created: 25 January 1998
** Rev 2.03: Support for 128 bit DP math. This file really ouught to
** be renamed!
** $Id: double.c,v 1.3 2010/11/01 14:10:27 asau Exp $
*******************************************************************/
/*
** Copyright (c) 1997-2001 John Sadler (john_sadler@alum.mit.edu)
** All rights reserved.
**
** Get the latest Ficl release at http://ficl.sourceforge.net
**
** I am interested in hearing from anyone who uses Ficl. If you have
** a problem, a success story, a defect, an enhancement request, or
** if you would like to contribute to the Ficl release, please
** contact me by email at the address above.
**
** L I C E N S E and D I S C L A I M E R
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
** ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
** SUCH DAMAGE.
*/
#include <stdint.h>
#include "ficl.h"
#if FICL_PLATFORM_HAS_2INTEGER
ficl2UnsignedQR ficl2UnsignedDivide(ficl2Unsigned q, ficlUnsigned y)
{
ficl2UnsignedQR result;
result.quotient = q / y;
/*
** Once we have the quotient, it's cheaper to calculate the
** remainder this way than with % (mod). --lch
*/
result.remainder = (ficlInteger)(q - (result.quotient * y));
return result;
}
#else /* FICL_PLATFORM_HAS_2INTEGER */
#define FICL_CELL_HIGH_BIT ((uintmax_t)1 << (FICL_BITS_PER_CELL-1))
#define UMOD_SHIFT (FICL_BITS_PER_CELL / 2)
#define UMOD_MASK ((1L << (FICL_BITS_PER_CELL / 2)) - 1)
/**************************************************************************
ficl2IntegerIsNegative
** Returns TRUE if the specified ficl2Unsigned has its sign bit set.
**************************************************************************/
int ficl2IntegerIsNegative(ficl2Integer x)
{
return (x.high < 0);
}
/**************************************************************************
ficl2IntegerNegate
** Negates an ficl2Unsigned by complementing and incrementing.
**************************************************************************/
ficl2Integer ficl2IntegerNegate(ficl2Integer x)
{
x.high = ~x.high;
x.low = ~x.low;
x.low ++;
if (x.low == 0)
x.high++;
return x;
}
/**************************************************************************
ficl2UnsignedMultiplyAccumulate
** Mixed precision multiply and accumulate primitive for number building.
** Multiplies ficl2Unsigned u by ficlUnsigned mul and adds ficlUnsigned add. Mul is typically
** the numeric base, and add represents a digit to be appended to the
** growing number.
** Returns the result of the operation
**************************************************************************/
ficl2Unsigned ficl2UnsignedMultiplyAccumulate(ficl2Unsigned u, ficlUnsigned mul, ficlUnsigned add)
{
ficl2Unsigned resultLo = ficl2UnsignedMultiply(u.low, mul);
ficl2Unsigned resultHi = ficl2UnsignedMultiply(u.high, mul);
resultLo.high += resultHi.low;
resultHi.low = resultLo.low + add;
if (resultHi.low < resultLo.low)
resultLo.high++;
resultLo.low = resultHi.low;
return resultLo;
}
/**************************************************************************
ficl2IntegerMultiply
** Multiplies a pair of ficlIntegers and returns an ficl2Integer result.
**************************************************************************/
ficl2Integer ficl2IntegerMultiply(ficlInteger x, ficlInteger y)
{
ficl2Unsigned prod;
int sign = 1;
if (x < 0)
{
sign = -sign;
x = -x;
}
if (y < 0)
{
sign = -sign;
y = -y;
}
prod = ficl2UnsignedMultiply(x, y);
if (sign > 0)
return FICL_2UNSIGNED_TO_2INTEGER(prod);
else
return ficl2IntegerNegate(FICL_2UNSIGNED_TO_2INTEGER(prod));
}
ficl2Integer ficl2IntegerDecrement(ficl2Integer x)
{
if (x.low == INT_MIN)
x.high--;
x.low--;
return x;
}
ficl2Unsigned ficl2UnsignedAdd(ficl2Unsigned x, ficl2Unsigned y)
{
ficl2Unsigned result;
int carry;
result.high = x.high + y.high;
result.low = x.low + y.low;
carry = ((x.low | y.low) & FICL_CELL_HIGH_BIT) && !(result.low & FICL_CELL_HIGH_BIT);
carry |= ((x.low & y.low) & FICL_CELL_HIGH_BIT);
if (carry)
{
result.high++;
}
return result;
}
/**************************************************************************
ficl2UnsignedMultiply
** Contributed by:
** Michael A. Gauland gaulandm@mdhost.cse.tek.com
**************************************************************************/
ficl2Unsigned ficl2UnsignedMultiply(ficlUnsigned x, ficlUnsigned y)
{
ficl2Unsigned result = { 0, 0 };
ficl2Unsigned addend;
addend.low = y;
addend.high = 0; /* No sign extension--arguments are unsigned */
while (x != 0)
{
if ( x & 1)
{
result = ficl2UnsignedAdd(result, addend);
}
x >>= 1;
addend = ficl2UnsignedArithmeticShiftLeft(addend);
}
return result;
}
/**************************************************************************
ficl2UnsignedSubtract
**
**************************************************************************/
ficl2Unsigned ficl2UnsignedSubtract(ficl2Unsigned x, ficl2Unsigned y)
{
ficl2Unsigned result;
result.high = x.high - y.high;
result.low = x.low - y.low;
if (x.low < y.low)
{
result.high--;
}
return result;
}
/**************************************************************************
ficl2UnsignedArithmeticShiftLeft
** 64 bit left shift
**************************************************************************/
ficl2Unsigned ficl2UnsignedArithmeticShiftLeft( ficl2Unsigned x )
{
ficl2Unsigned result;
result.high = x.high << 1;
if (x.low & FICL_CELL_HIGH_BIT)
{
result.high++;
}
result.low = x.low << 1;
return result;
}
/**************************************************************************
ficl2UnsignedArithmeticShiftRight
** 64 bit right shift (unsigned - no sign extend)
**************************************************************************/
ficl2Unsigned ficl2UnsignedArithmeticShiftRight( ficl2Unsigned x )
{
ficl2Unsigned result;
result.low = x.low >> 1;
if (x.high & 1)
{
result.low |= FICL_CELL_HIGH_BIT;
}
result.high = x.high >> 1;
return result;
}
/**************************************************************************
ficl2UnsignedOr
** 64 bit bitwise OR
**************************************************************************/
ficl2Unsigned ficl2UnsignedOr( ficl2Unsigned x, ficl2Unsigned y )
{
ficl2Unsigned result;
result.high = x.high | y.high;
result.low = x.low | y.low;
return result;
}
/**************************************************************************
ficl2UnsignedCompare
** Return -1 if x < y; 0 if x==y, and 1 if x > y.
**************************************************************************/
int ficl2UnsignedCompare(ficl2Unsigned x, ficl2Unsigned y)
{
if (x.high > y.high)
return 1;
if (x.high < y.high)
return -1;
/* High parts are equal */
if (x.low > y.low)
return 1;
else if (x.low < y.low)
return -1;
return 0;
}
/**************************************************************************
ficl2UnsignedDivide
** Portable versions of ficl2Multiply and ficl2Divide in C
** Contributed by:
** Michael A. Gauland gaulandm@mdhost.cse.tek.com
**************************************************************************/
ficl2UnsignedQR ficl2UnsignedDivide(ficl2Unsigned q, ficlUnsigned y)
{
ficl2UnsignedQR result;
ficl2Unsigned quotient;
ficl2Unsigned subtrahend;
ficl2Unsigned mask;
quotient.low = 0;
quotient.high = 0;
subtrahend.low = y;
subtrahend.high = 0;
mask.low = 1;
mask.high = 0;
while ((ficl2UnsignedCompare(subtrahend, q) < 0) &&
(subtrahend.high & FICL_CELL_HIGH_BIT) == 0)
{
mask = ficl2UnsignedArithmeticShiftLeft(mask);
subtrahend = ficl2UnsignedArithmeticShiftLeft(subtrahend);
}
while (mask.low != 0 || mask.high != 0)
{
if (ficl2UnsignedCompare(subtrahend, q) <= 0)
{
q = ficl2UnsignedSubtract( q, subtrahend);
quotient = ficl2UnsignedOr(quotient, mask);
}
mask = ficl2UnsignedArithmeticShiftRight(mask);
subtrahend = ficl2UnsignedArithmeticShiftRight(subtrahend);
}
result.quotient = quotient;
result.remainder = q.low;
return result;
}
#endif /* !FICL_PLATFORM_HAS_2INTEGER */
/**************************************************************************
ficl2IntegerAbsoluteValue
** Returns the absolute value of an ficl2Unsigned
**************************************************************************/
ficl2Integer ficl2IntegerAbsoluteValue(ficl2Integer x)
{
if (ficl2IntegerIsNegative(x))
return ficl2IntegerNegate(x);
return x;
}
/**************************************************************************
ficl2IntegerDivideFloored
**
** FROM THE FORTH ANS...
** Floored division is integer division in which the remainder carries
** the sign of the divisor or is zero, and the quotient is rounded to
** its arithmetic floor. Symmetric division is integer division in which
** the remainder carries the sign of the dividend or is zero and the
** quotient is the mathematical quotient rounded towards zero or
** truncated. Examples of each are shown in tables 3.3 and 3.4.
**
** Table 3.3 - Floored Division Example
** Dividend Divisor Remainder Quotient
** -------- ------- --------- --------
** 10 7 3 1
** -10 7 4 -2
** 10 -7 -4 -2
** -10 -7 -3 1
**
**
** Table 3.4 - Symmetric Division Example
** Dividend Divisor Remainder Quotient
** -------- ------- --------- --------
** 10 7 3 1
** -10 7 -3 -1
** 10 -7 3 -1
** -10 -7 -3 1
**************************************************************************/
ficl2IntegerQR ficl2IntegerDivideFloored(ficl2Integer num, ficlInteger den)
{
ficl2IntegerQR qr;
ficl2UnsignedQR uqr;
int signRem = 1;
int signQuot = 1;
if (ficl2IntegerIsNegative(num))
{
num = ficl2IntegerNegate(num);
signQuot = -signQuot;
}
if (den < 0)
{
den = -den;
signRem = -signRem;
signQuot = -signQuot;
}
uqr = ficl2UnsignedDivide(FICL_2INTEGER_TO_2UNSIGNED(num), (ficlUnsigned)den);
qr = FICL_2UNSIGNEDQR_TO_2INTEGERQR(uqr);
if (signQuot < 0)
{
qr.quotient = ficl2IntegerNegate(qr.quotient);
if (qr.remainder != 0)
{
qr.quotient = ficl2IntegerDecrement(qr.quotient);
qr.remainder = den - qr.remainder;
}
}
if (signRem < 0)
qr.remainder = -qr.remainder;
return qr;
}
/**************************************************************************
ficl2IntegerDivideSymmetric
** Divide an ficl2Unsigned by a ficlInteger and return a ficlInteger quotient and a
** ficlInteger remainder. The absolute values of quotient and remainder are not
** affected by the signs of the numerator and denominator (the operation
** is symmetric on the number line)
**************************************************************************/
ficl2IntegerQR ficl2IntegerDivideSymmetric(ficl2Integer num, ficlInteger den)
{
ficl2IntegerQR qr;
ficl2UnsignedQR uqr;
int signRem = 1;
int signQuot = 1;
if (ficl2IntegerIsNegative(num))
{
num = ficl2IntegerNegate(num);
signRem = -signRem;
signQuot = -signQuot;
}
if (den < 0)
{
den = -den;
signQuot = -signQuot;
}
uqr = ficl2UnsignedDivide(FICL_2INTEGER_TO_2UNSIGNED(num), (ficlUnsigned)den);
qr = FICL_2UNSIGNEDQR_TO_2INTEGERQR(uqr);
if (signRem < 0)
qr.remainder = -qr.remainder;
if (signQuot < 0)
qr.quotient = ficl2IntegerNegate(qr.quotient);
return qr;
}