55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/* Extended Module Player
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* Copyright (C) 1996-2024 Claudio Matsuoka and Hipolito Carraro Jr
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "common.h"
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#include "rng.h"
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#include <time.h>
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static unsigned libxmp_random_step_xorshift32(unsigned state)
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{
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if (state == 0) state = 1;
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state ^= state << 13u;
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state ^= state >> 17u;
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return state << 5u;
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}
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unsigned libxmp_get_random(struct rng_state *rng, unsigned range)
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{
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unsigned state = libxmp_random_step_xorshift32(rng->state);
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rng->state = state;
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return (uint64)range * state >> 32u;
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}
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void libxmp_set_random(struct rng_state *rng, unsigned state)
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{
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rng->state = state;
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}
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void libxmp_init_random(struct rng_state *rng)
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{
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rng->state = (unsigned) time(NULL);
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libxmp_get_random(rng, 0);
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libxmp_get_random(rng, 0);
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libxmp_get_random(rng, 0);
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}
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