cf99fb40c9
Squashed commit of the following:
libs/libxx: Fix some confusing in naming. If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
libs/: Fix paths in moved library directories.
libs: Brute force move of libc, libnx, and libxx to libs. Cannot yet build it in that configuration.
94 lines
3.4 KiB
C
94 lines
3.4 KiB
C
/****************************************************************************
|
|
* libs/libc/misc/lib_umul32.c
|
|
*
|
|
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* 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. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
|
|
* COPYRIGHT OWNER 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.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/lib/math32.h>
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: umul32
|
|
*
|
|
* Description:
|
|
* Multiply two 32-bit values, factor1 and factor2, and return the
|
|
* full 64-bit product.
|
|
*
|
|
* Input Parameters:
|
|
* factor1 and factor2 - The values to be multiplied
|
|
* product - The location to return the product of the two values.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void umul32(uint32_t factor1, uint32_t factor2, FAR struct uint64_s *product)
|
|
{
|
|
struct uint64_s part2;
|
|
uint32_t ms1;
|
|
uint32_t ls1;
|
|
uint32_t ms2;
|
|
uint32_t ls2;
|
|
uint32_t tmp;
|
|
|
|
/* factor1 = ms1 << 16 + ls1
|
|
* factor2 = ms2 << 16 + ls2
|
|
*/
|
|
|
|
ms1 = factor1 >> 16;
|
|
ls1 = factor1 & 0x0000ffff;
|
|
ms2 = factor2 >> 16;
|
|
ls2 = factor2 & 0x0000ffff;
|
|
|
|
/* factor1 * factor2 = (ms1 * ms2 << 32) +
|
|
* ls1 * (ms2 << 16) + ls2 * (ms1 << 16) +
|
|
* ls1 * ls2
|
|
* part1 = (ms1 * ms2 << 32) + ls1 * ls2
|
|
* part2 = ls1 * (ms2 << 16) + ls2 * (ms1 << 16)
|
|
* factor1 * factor2 = part1 + part2
|
|
*/
|
|
|
|
product->ms = ms1 * ms2;
|
|
product->ls = ls1 * ls2;
|
|
|
|
tmp = ls1 * ms2 + ls2 * ms1;
|
|
part2.ms = tmp >> 16;
|
|
part2.ls = tmp << 16;
|
|
|
|
uadd64(product, &part2, product);
|
|
}
|