mirror of https://github.com/google/gemma.cpp.git
49 lines
1.2 KiB
Common Lisp
49 lines
1.2 KiB
Common Lisp
/*
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* Copyright (c) 2021 The Khronos Group Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file 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.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,
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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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kernel void Collatz(
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global int * const result
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) {
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const size_t gli = get_global_id(0);
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const size_t ind = gli - get_global_offset(0);
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int steps = 0;
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ulong n = gli + 1;
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while (n != 1) {
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if (steps > INT_MAX - 3) {
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steps = 0;
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break;
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}
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if (n & 1) {
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ulong m = 3 * n + 1;
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if (m < n) {
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steps = -steps - 1;
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break;
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}
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n = m >> 1;
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steps += 2;
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}
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else {
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n >>= 1;
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++steps;
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}
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}
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result[ind] = steps;
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}
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