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/*
* This file is part of the libpayload project.
*
* Copyright 2014 Google Inc.
*
* 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.
* 3. 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 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 <libpayload-config.h>
#include <stdlib.h>
#if !IS_ENABLED(CONFIG_LP_LITTLE_ENDIAN)
#error this code is for little endian only
#endif
union overlay64 {
uint64_t longw;
struct {
uint32_t lower;
uint32_t higher;
} words;
};
uint64_t __ashldi3(uint64_t num, unsigned shift)
{
union overlay64 output;
output.longw = num;
if (shift >= 32) {
output.words.higher = output.words.lower << (shift - 32);
output.words.lower = 0;
} else {
if (!shift)
return num;
output.words.higher = (output.words.higher << shift) |
(output.words.lower >> (32 - shift));
output.words.lower = output.words.lower << shift;
}
return output.longw;
}
uint64_t __lshrdi3(uint64_t num, unsigned shift)
{
union overlay64 output;
output.longw = num;
if (shift >= 32) {
output.words.lower = output.words.higher >> (shift - 32);
output.words.higher = 0;
} else {
if (!shift)
return num;
output.words.lower = output.words.lower >> shift |
(output.words.higher << (32 - shift));
output.words.higher = output.words.higher >> shift;
}
return output.longw;
}
#define MAX_32BIT_UINT ((((uint64_t)1) << 32) - 1)
static uint64_t _64bit_divide(uint64_t dividend,
uint64_t divider, uint64_t *rem_p)
{
uint64_t result = 0;
/*
* If divider is zero - let the rest of the system care about the
* exception.
*/
if (!divider)
return 1/(uint32_t)divider;
/* As an optimization, let's not use 64 bit division unless we must. */
if (dividend <= MAX_32BIT_UINT) {
if (divider > MAX_32BIT_UINT) {
result = 0;
if (rem_p)
*rem_p = divider;
} else {
result = (uint32_t) dividend / (uint32_t) divider;
if (rem_p)
*rem_p = (uint32_t) dividend %
(uint32_t) divider;
}
return result;
}
while (divider <= dividend) {
uint64_t locald = divider;
uint64_t limit = __lshrdi3(dividend, 1);
int shifts = 0;
while (locald <= limit) {
shifts++;
locald = locald + locald;
}
result |= __ashldi3(1, shifts);
dividend -= locald;
}
if (rem_p)
*rem_p = dividend;
return result;
}
uint64_t __udivdi3(uint64_t num, uint64_t den)
{
return _64bit_divide(num, den, NULL);
}
uint64_t __umoddi3(uint64_t num, uint64_t den)
{
uint64_t v = 0;
_64bit_divide(num, den, &v);
return v;
}
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