66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
/****************************************************************************
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* libs/libc/misc/lib_uadd64.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/lib/math32.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: uadd64
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*
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* Description:
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* Add two 64-bit values and return a 64-bit sum.
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*
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* Input Parameters:
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* term1 and term2 - The values to be added
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* sum - The location to return the product of the two values. sum may
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* be one of term1 or term2
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*
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****************************************************************************/
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void uadd64(FAR const struct uint64_s *term1,
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FAR const struct uint64_s *term2,
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FAR struct uint64_s *sum)
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{
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/* Get the MS part of the sum */
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sum->ms = term1->ms + term2->ms;
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/* Check for carry, i.e., that is when:
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*
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* term1->ls + term2->ls > UINT32_MAX
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*/
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if ((UINT32_MAX - term1->ls) > term2->ls)
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{
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sum->ms++;
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}
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/* Get the LS part of the sum */
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sum->ls = term1->ls + term2->ls;
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}
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