81 lines
3.0 KiB
C
81 lines
3.0 KiB
C
/****************************************************************************
|
|
* libc/fixedmath/lib_uadd32x64.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/math32.h>
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: uadd32x64
|
|
*
|
|
* Description:
|
|
* Add a 32-bit value to a 64-bit values and return the truncated 64-bit
|
|
* sum.
|
|
*
|
|
* Input Parameters:
|
|
* term1 and term2 - The values to be added
|
|
* sum - The location to return the product of the two values. sum may
|
|
* be one of term1 or term2
|
|
*
|
|
****************************************************************************/
|
|
|
|
void uadd32x64(uint32_t term1, FAR const struct uint64_s *term2,
|
|
FAR struct uint64_s *sum)
|
|
{
|
|
/* Get the MS part of the sum */
|
|
|
|
sum->ms = term2->ms;
|
|
|
|
/* Check for carry, i.e., that is when:
|
|
*
|
|
* term1 + term2->ls > UINT32_MAX
|
|
*/
|
|
|
|
if ((UINT32_MAX - term1) > term2->ls)
|
|
{
|
|
sum->ms++;
|
|
}
|
|
|
|
/* Get the LS part of the sum */
|
|
|
|
sum->ls = term1 + term2->ls;
|
|
}
|