71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/*
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* Licensed to the OpenAirInterface (OAI) Software Alliance 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.
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* The OpenAirInterface Software Alliance licenses this file to You under
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* the OAI Public License, Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.openairinterface.org/?page_id=698
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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,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*-------------------------------------------------------------------------------
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* For more information about the OpenAirInterface (OAI) Software Alliance:
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* contact@openairinterface.org
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*/
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//----------------------------------------------
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//
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// Integer square root. Take the square root of an integer.
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//
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#define step(shift) \
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if((0x40000000l >> shift) + root <= value) \
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{ \
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value -= (0x40000000l >> shift) + root; \
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root = (root >> 1) | (0x40000000l >> shift); \
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} \
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else \
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{ \
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root = root >> 1; \
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}
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int
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iSqrt(int value)
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{
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int root = 0;
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step( 0);
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step( 2);
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step( 4);
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step( 6);
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step( 8);
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step(10);
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step(12);
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step(14);
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step(16);
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step(18);
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step(20);
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step(22);
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step(24);
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step(26);
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step(28);
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step(30);
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// round to the nearest integer, cuts max error in half
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if(root < value) {
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++root;
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}
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return root;
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}
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