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101 lines
3.9 KiB
C
101 lines
3.9 KiB
C
/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
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╚──────────────────────────────────────────────────────────────────────────────╝
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│ │
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│ Musl Libc │
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│ Copyright © 2005-2014 Rich Felker, et al. │
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│ │
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│ Permission is hereby granted, free of charge, to any person obtaining │
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│ a copy of this software and associated documentation files (the │
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│ "Software"), to deal in the Software without restriction, including │
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│ without limitation the rights to use, copy, modify, merge, publish, │
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│ distribute, sublicense, and/or sell copies of the Software, and to │
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│ permit persons to whom the Software is furnished to do so, subject to │
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│ the following conditions: │
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│ │
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│ The above copyright notice and this permission notice shall be │
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│ included in 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, │
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│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
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│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
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│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
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│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
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│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
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│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "third_party/musl/rand48.h"
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#include "libc/str/str.h"
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asm(".ident\t\"\\n\\n\
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Musl libc (MIT License)\\n\
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Copyright 2005-2014 Rich Felker, et. al.\"");
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asm(".include \"libc/disclaimer.inc\"");
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// clang-format off
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static unsigned short __seed48[7] = { 0, 0, 0, 0xe66d, 0xdeec, 0x5, 0xb };
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static uint64_t __rand48_step(unsigned short *xi, unsigned short *lc)
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{
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uint64_t a, x;
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x = xi[0] | xi[1]+0U<<16 | xi[2]+0ULL<<32;
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a = lc[0] | lc[1]+0U<<16 | lc[2]+0ULL<<32;
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x = a*x + lc[3];
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xi[0] = x;
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xi[1] = x>>16;
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xi[2] = x>>32;
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return x & 0xffffffffffffull;
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}
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double erand48(unsigned short s[3])
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{
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union {
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uint64_t u;
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double f;
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} x = { 0x3ff0000000000000ULL | __rand48_step(s, __seed48+3)<<4 };
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return x.f - 1.0;
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}
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double drand48(void)
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{
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return erand48(__seed48);
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}
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void lcong48(unsigned short p[7])
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{
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memcpy(__seed48, p, sizeof __seed48);
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}
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long nrand48(unsigned short s[3])
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{
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return __rand48_step(s, __seed48+3) >> 17;
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}
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long lrand48(void)
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{
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return nrand48(__seed48);
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}
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long jrand48(unsigned short s[3])
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{
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return (int32_t)(__rand48_step(s, __seed48+3) >> 16);
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}
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long mrand48(void)
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{
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return jrand48(__seed48);
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}
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unsigned short *seed48(unsigned short s[3])
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{
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static unsigned short p[3];
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memcpy(p, __seed48, sizeof p);
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memcpy(__seed48, s, sizeof p);
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return p;
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}
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void srand48(long seed)
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{
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seed48((unsigned short [3]){ 0x330e, seed, seed>>16 });
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}
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