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Diffstat (limited to 'newlib/libc/stdlib/rand48.c')
| -rw-r--r-- | newlib/libc/stdlib/rand48.c | 178 |
1 files changed, 0 insertions, 178 deletions
diff --git a/newlib/libc/stdlib/rand48.c b/newlib/libc/stdlib/rand48.c deleted file mode 100644 index c65af12cd..000000000 --- a/newlib/libc/stdlib/rand48.c +++ /dev/null @@ -1,178 +0,0 @@ -/* - * Copyright (c) 1993 Martin Birgmeier - * All rights reserved. - * - * You may redistribute unmodified or modified versions of this source - * code provided that the above copyright notice and this and the - * following conditions are retained. - * - * This software is provided ``as is'', and comes with no warranties - * of any kind. I shall in no event be liable for anything that happens - * to anyone/anything when using this software. - */ - -/* -FUNCTION - <<rand48>>, <<drand48>>, <<erand48>>, <<lrand48>>, <<nrand48>>, <<mrand48>>, <<jrand48>>, <<srand48>>, <<seed48>>, <<lcong48>> ---pseudo random number generators and initialization routines - -INDEX - rand48 -INDEX - drand48 -INDEX - erand48 -INDEX - lrand48 -INDEX - nrand48 -INDEX - mrand48 -INDEX - jrand48 -INDEX - srand48 -INDEX - seed48 -INDEX - lcong48 - -ANSI_SYNOPSIS - #include <stdlib.h> - double drand48(void); - double erand48(unsigned short <[xseed]>[3]); - long lrand48(void); - long nrand48(unsigned short <[xseed]>[3]); - long mrand48(void); - long jrand48(unsigned short <[xseed]>[3]); - void srand48(long <[seed]>); - unsigned short *seed48(unsigned short <[xseed]>[3]); - void lcong48(unsigned short <[p]>[7]); - -TRAD_SYNOPSIS - #include <stdlib.h> - double drand48(); - - double erand48(<[xseed]>) - unsigned short <[xseed]>[3]; - - long lrand48(); - - long nrand48(<[xseed]>) - unsigned short <[xseed]>[3]; - - long mrand48(); - - long jrand48(<[xseed]>) - unsigned short <[xseed]>[3]; - - void srand48(<[seed]>) - long <[seed]>; - - unsigned short *seed48(<[xseed]>) - unsigned short <[xseed]>[3]; - - void lcong48(<[p]>) - unsigned short <[p]>[7]; - -DESCRIPTION -The <<rand48>> family of functions generates pseudo-random numbers -using a linear congruential algorithm working on integers 48 bits in size. -The particular formula employed is -r(n+1) = (a * r(n) + c) mod m -where the default values are -for the multiplicand a = 0xfdeece66d = 25214903917 and -the addend c = 0xb = 11. The modulo is always fixed at m = 2 ** 48. -r(n) is called the seed of the random number generator. - -For all the six generator routines described next, the first -computational step is to perform a single iteration of the algorithm. - -<<drand48>> and <<erand48>> -return values of type double. The full 48 bits of r(n+1) are -loaded into the mantissa of the returned value, with the exponent set -such that the values produced lie in the interval [0.0, 1.0]. - -<<lrand48>> and <<nrand48>> -return values of type long in the range -[0, 2**31-1]. The high-order (31) bits of -r(n+1) are loaded into the lower bits of the returned value, with -the topmost (sign) bit set to zero. - -<<mrand48>> and <<jrand48>> -return values of type long in the range -[-2**31, 2**31-1]. The high-order (32) bits of -r(n+1) are loaded into the returned value. - -<<drand48>>, <<lrand48>>, and <<mrand48>> -use an internal buffer to store r(n). For these functions -the initial value of r(0) = 0x1234abcd330e = 20017429951246. - -On the other hand, <<erand48>>, <<nrand48>>, and <<jrand48>> -use a user-supplied buffer to store the seed r(n), -which consists of an array of 3 shorts, where the zeroth member -holds the least significant bits. - -All functions share the same multiplicand and addend. - -<<srand48>> is used to initialize the internal buffer r(n) of -<<drand48>>, <<lrand48>>, and <<mrand48>> -such that the 32 bits of the seed value are copied into the upper 32 bits -of r(n), with the lower 16 bits of r(n) arbitrarily being set to 0x330e. -Additionally, the constant multiplicand and addend of the algorithm are -reset to the default values given above. - -<<seed48>> also initializes the internal buffer r(n) of -<<drand48>>, <<lrand48>>, and <<mrand48>>, -but here all 48 bits of the seed can be specified in an array of 3 shorts, -where the zeroth member specifies the lowest bits. Again, -the constant multiplicand and addend of the algorithm are -reset to the default values given above. -<<seed48>> returns a pointer to an array of 3 shorts which contains -the old seed. -This array is statically allocated, thus its contents are lost after -each new call to <<seed48>>. - -Finally, <<lcong48>> allows full control over the multiplicand and -addend used in <<drand48>>, <<erand48>>, <<lrand48>>, <<nrand48>>, -<<mrand48>>, and <<jrand48>>, -and the seed used in <<drand48>>, <<lrand48>>, and <<mrand48>>. -An array of 7 shorts is passed as parameter; the first three shorts are -used to initialize the seed; the second three are used to initialize the -multiplicand; and the last short is used to initialize the addend. -It is thus not possible to use values greater than 0xffff as the addend. - -Note that all three methods of seeding the random number generator -always also set the multiplicand and addend for any of the six -generator calls. - -For a more powerful random number generator, see <<random>>. - -PORTABILITY -SUS requires these functions. - -No supporting OS subroutines are required. -*/ - -#include "rand48.h" - -void -_DEFUN (__dorand48, (r, xseed), - struct _reent *r _AND - unsigned short xseed[3]) -{ - unsigned long accu; - unsigned short temp[2]; - - accu = (unsigned long) __rand48_mult[0] * (unsigned long) xseed[0] + - (unsigned long) __rand48_add; - temp[0] = (unsigned short) accu; /* lower 16 bits */ - accu >>= sizeof(unsigned short) * 8; - accu += (unsigned long) __rand48_mult[0] * (unsigned long) xseed[1] + - (unsigned long) __rand48_mult[1] * (unsigned long) xseed[0]; - temp[1] = (unsigned short) accu; /* middle 16 bits */ - accu >>= sizeof(unsigned short) * 8; - accu += __rand48_mult[0] * xseed[2] + __rand48_mult[1] * xseed[1] + __rand48_mult[2] * xseed[0]; - xseed[0] = temp[0]; - xseed[1] = temp[1]; - xseed[2] = (unsigned short) accu; -} |