0,0 → 1,200 |
/* |
* Copyright (c) 2006 Josef Cejka |
* All rights reserved. |
* |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* are met: |
* |
* - Redistributions of source code must retain the above copyright |
* notice, this list of conditions and the following disclaimer. |
* - 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. |
* - The name of the author may not be used to endorse or promote products |
* derived from this software without specific prior written permission. |
* |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. |
*/ |
|
/** @addtogroup genarch |
* @{ |
*/ |
/** @file |
*/ |
|
#include <genarch/softint/division.h> |
|
#define ABSVAL(x) ((x) > 0 ? (x) : -(x)) |
#define SGN(x) ((x) >= 0 ? 1 : 0) |
|
static unsigned int divandmod32(unsigned int a, unsigned int b, |
unsigned int *remainder) |
{ |
unsigned int result; |
int steps = sizeof(unsigned int) * 8; |
|
*remainder = 0; |
result = 0; |
|
if (b == 0) { |
/* FIXME: division by zero */ |
return 0; |
} |
|
if (a < b) { |
*remainder = a; |
return 0; |
} |
|
for (; steps > 0; steps--) { |
/* shift one bit to remainder */ |
*remainder = ((*remainder) << 1) | (( a >> 31) & 0x1); |
result <<= 1; |
|
if (*remainder >= b) { |
*remainder -= b; |
result |= 0x1; |
} |
a <<= 1; |
} |
|
return result; |
} |
|
|
static unsigned long long divandmod64(unsigned long long a, |
unsigned long long b, unsigned long long *remainder) |
{ |
unsigned long long result; |
int steps = sizeof(unsigned long long) * 8; |
|
*remainder = 0; |
result = 0; |
|
if (b == 0) { |
/* FIXME: division by zero */ |
return 0; |
} |
|
if (a < b) { |
*remainder = a; |
return 0; |
} |
|
for (; steps > 0; steps--) { |
/* shift one bit to remainder */ |
*remainder = ((*remainder) << 1) | ((a >> 63) & 0x1); |
result <<= 1; |
|
if (*remainder >= b) { |
*remainder -= b; |
result |= 0x1; |
} |
a <<= 1; |
} |
|
return result; |
} |
|
/* 32bit integer division */ |
int __divsi3(int a, int b) |
{ |
unsigned int rem; |
int result; |
|
result = (int) divandmod32(ABSVAL(a), ABSVAL(b), &rem); |
|
if (SGN(a) == SGN(b)) |
return result; |
return -result; |
} |
|
/* 64bit integer division */ |
long long __divdi3(long long a, long long b) |
{ |
unsigned long long rem; |
long long result; |
|
result = (long long) divandmod64(ABSVAL(a), ABSVAL(b), &rem); |
|
if (SGN(a) == SGN(b)) |
return result; |
return -result; |
} |
|
/* 32bit unsigned integer division */ |
unsigned int __udivsi3(unsigned int a, unsigned int b) |
{ |
unsigned int rem; |
return divandmod32(a, b, &rem); |
} |
|
/* 64bit unsigned integer division */ |
unsigned long long __udivdi3(unsigned long long a, unsigned long long b) |
{ |
unsigned long long rem; |
return divandmod64(a, b, &rem); |
} |
|
/* 32bit remainder of the signed division */ |
int __modsi3(int a, int b) |
{ |
unsigned int rem; |
divandmod32(a, b, &rem); |
|
/* if divident is negative, remainder must be too */ |
if (!(SGN(a))) { |
return -((int) rem); |
} |
|
return (int) rem; |
} |
|
/* 64bit remainder of the signed division */ |
long long __moddi3(long long a,long long b) |
{ |
unsigned long long rem; |
divandmod64(a, b, &rem); |
|
/* if divident is negative, remainder must be too */ |
if (!(SGN(a))) { |
return -((long long) rem); |
} |
|
return (long long) rem; |
} |
|
/* 32bit remainder of the unsigned division */ |
unsigned int __umodsi3(unsigned int a, unsigned int b) |
{ |
unsigned int rem; |
divandmod32(a, b, &rem); |
return rem; |
} |
|
/* 64bit remainder of the unsigned division */ |
unsigned long long __umoddi3(unsigned long long a, unsigned long long b) |
{ |
unsigned long long rem; |
divandmod64(a, b, &rem); |
return rem; |
} |
|
unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b, |
unsigned long long *c) |
{ |
return divandmod64(a, b, c); |
} |
|
/** @} |
*/ |