glibc/stdlib/random.c
Roland McGrath b20e47cb14 Tue Mar 19 14:18:42 1996 Roland McGrath <roland@charlie-brown.gnu.ai.mit.edu>
* sysdeps/unix/bsd/pause.c: Moved to sysdeps/unix/common/pause.c.

Mon Mar  4 20:17:28 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* sysdeps/unix/sysv/linux/adjtime.c: Use INT_MAX instead of LONG_MAX.

	* sysdeps/unix/sysv/Makefile (sysdep_routines): Don't add s_getdents.

	* sysdeps/unix/sysv/linux/Makefile (sysdep_routines): Don't add mount,
	umount.

	* sysdeps/alpha/__math.h (atan, cabs): New functions.

	* sysdeps/unix/sysv/linux/alpha/sigsuspend.S: new file (syscall
 	expects set-value, not pointer to it).

Sun Feb 25 22:36:10 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* sysdeps/unix/sysv/linux/alpha/profil-counter.h: New file.

	* gmon/gmon.c (__bb_head): new variable.
	(write_hist, write_call_graph, write_bb_counts): new functions.
	(_mcleanup): modified to call above functions instead of directly
 	writing out gmon.out.
	* gmon/sys/gmon.h (struct __bb): New type.
	(struct gmonhdr): Type removed.
	(struct gmonparam): New member `log_hashfraction'.
	(GMONVERSION): Macro removed.

	* gmon/sys/gmon_out.h, gmon/bb_exit_func.c,
 	sysdeps/generic/bb_init_func.c, sysdeps/alpha/bb_init_func.S: new
 	files.
	* gmon/Makefile (headers): Add sys/gmon_out.h.
	(routines): Add bb_init_func, bb_exit_func.

	* gmon/mcount.c: Avoid integer division.

Wed Feb 21 23:56:41 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* sysdeps/alpha/setjmp.S: switched order in which sp and fp are
 	passed to match what __sigsetjmp_aux() expects.

Tue Feb 20 11:33:46 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* sysdeps/unix/sysv/linux/alpha/syscalls.list (select, bind,
 	connect, getpeername, getsockname, listen, recv, recvfrom,
 	recvmsg, send, sendmsg, sendto, setsockopt, shutdown, socketpair):
 	added to override same-name assembly file in the parent directory.

	* stdlib/stdlib.h: add include of sys/types.h in front of random
 	etc declarations to ensure int32_t is declared.

	* stdlib/random.c, stdlib/random_r.c: replaced "long int" by int32_t
	where 32 bit integers are required.  Also change LONG_MAX into
	0x7fffffff since the intent is to turn off the sign bit in a
	32 bit integer.

	* time/offtime.c (__offtime): Use Paul Eggert's code to deal
	with very large values for "days" (e.g., 64 bit values).

Mon Feb 19 22:22:12 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* stdlib/stdlib.h (__random, __random_r, random_r, struct
 	random_data): use int32_t instead of `long int'.

Sat Feb 17 11:29:29 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* sysdeps/unix/sysv/linux/alpha/ioperm.c: new file.

	* sysdeps/alpha/ffs.S: new file.

	* sysdeps/alpha/fabs.c: File removed.

	* time/tzfile.c (__tzfile_read): counter variable is i, *not*
	num_transitions!

	* time/offtime.c: make capable of dealing with very large (64 bit)
 	time_t values.  Use old algorithm until a year is reached that
	is an integer multiple of 400, then use DAYS_PER_400_YEARS to
	do the remainder in a single division.

	* sysdeps/generic/ffs.c (ffs): fix variable declarations to
	be unsigned int, not unsigned long.

	* string/test-ffs.c (main): add test case with all upper bits
	set.

	* stdlib/tst-strtol.c: add tests cases for machines where
	sizeof(long)==8.

	* stdlib/testrand.c (main): disallow rand() to return negative
 	integers.

	* stdlib/testmb.c (main): fix format to use %lx instead of %x.

	* stdlib/stdlib.h: on 64 bit machines, declare
	struct random_data, __random(),  __random_r, and random_r to
	return "int" instead of "long int".

	* stdlib/random_r.c: 64 bit machines use "int" instead of "long
 	int".  Similarly, use INT_MAX instead of LONG_MAX.

	* stdlib/random.c: on 64 bit machines, randtbl[] and __random[]
 	need to operate on "int" instead of "long int".

	* locale/locfile-hash.c (compute_hashval): make shifted constant
	a long to avoid loosing bits on 64 bit machines.

	* dirent/tst-seekdir.c (main): fix confusing comment; print
	a line to mark point where directory is rewound.

Fri Feb 16 15:01:49 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* time/strftime.c (strftime): any hour > 11 is PM (not > 12!).

Wed Feb 14 00:21:17 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* sysdeps/unix/sysv/linux/alpha/Makefile,
	sysdeps/unix/sysv/linux/alpha/brk.S,
	sysdeps/unix/sysv/linux/alpha/fpu_control.c,
	sysdeps/unix/sysv/linux/alpha/fpu_control.h,
	sysdeps/unix/sysv/linux/alpha/ieee_get_fp_control.S,
	sysdeps/unix/sysv/linux/alpha/ieee_set_fp_control.S,
	sysdeps/unix/sysv/linux/alpha/pipe.S,
	sysdeps/unix/sysv/linux/alpha/setfpucw.c,
	sysdeps/unix/sysv/linux/alpha/sigprocmask.c,
	sysdeps/unix/sysv/linux/alpha/speed.c,
	sysdeps/unix/sysv/linux/alpha/start.S,
	sysdeps/unix/sysv/linux/alpha/syscall.S,
	sysdeps/unix/sysv/linux/alpha/syscalls.list,
	sysdeps/unix/sysv/linux/alpha/alpha/regdef.h,
	sysdeps/unix/sysv/linux/alpha/sysdep.S,
	sysdeps/unix/sysv/linux/alpha/sysdep.h: New files.

	* sysdeps/alpha/setjmp_aux.c (__sigsetjmp_aux): restore return
 	address register before returning (gcc 2.7.1 doesn't do it,
 	presumably because $26 is declared as a global variable).

	* sysdeps/unix/sysv/linux/sys/mman.h: msync was missing "flags"
	argument.

	* sysdeps/unix/alarm.c (alarm): do roundup using test & increment
	instead of multiplication.

	* sysdeps/posix/sleep.c (sleep): initialize sa_mask to mask of
	currently blocked signals instead of the empty mask to ensure
	that execution of alarm handler occurs with none of the currently
	blocked signals enabled.

	* sysdeps/unix/alpha/sysdep.h: new file (adapted from OSF/1 version).

	* sysdeps/unix/bsd/osf/alpha/sysdep.h: include
 	sysdeps/unix/alpha/sysdep.h and removed definitions now in that file.

	* sysdeps/alpha/divrem.S, sysdeps/alpha/htonl.S,
	sysdeps/alpha/htons.S, sysdeps/alpha/machine-gmon.h,
	sysdeps/alpha/_mcount.S, sysdeps/alpha/ntohl.s, sysdeps/alpha/ntohs.s,
	sysdeps/alpha/strlen.S: New files.

	* sysdeps/alpha/divl.S, sysdeps/alpha/divlu.S, sysdeps/alpha/divq.S,
	sysdeps/alpha/divqu.S, sysdeps/alpha/divrem.m4,
	sysdeps/alpha/macros.m4, sysdeps/alpha/reml.S, sysdeps/alpha/remlu.S,
	sysdeps/alpha/remq.S, sysdeps/alpha/remqu.S, sysdeps/alpha/strlen.c:
 	Removed.

	* sysdeps/generic/sbrk.c (__sbrk): argument is of type ptrdiff_t, not
	int.

	* sysdeps/alpha/__longjmp.c (__longjmp): moved dummy while loop
	to end of function to avoid a jump across NOPs.

	* sysdeps/alpha/Makefile (sysdep_routines): Removed all rules
 	pertaining to integer division/remainder routines since new code
 	doesn't require them.

	* sunrpc/xdr_mem.c, sunrpc/xdr_stdio.c: Use 4 instead of sizeof(long)
	where 32 bit quantities are consumed/stored.  Various other minor
	64-bit cleanups (casting).

	* sunrpc/xdr.c (xdr_int): test for sizeof(int)==4 to determine
 	whether xdr_long or xdr_short should be used to encode an int.
  	Notice that an xdr_long is 4 bytes independent of the architecture
	(otherwise no Alpha could interoperate with existing NFS servers,
 	for example).  Ditto for enums.

	* sunrpc/svc_udp.c (svcudp_recv): changed test from 4*sizeof(u_long)
	to 16 since it really wants 16 bytes.

	* sunrpc/svc.c (maskp): changed from u_long* to u_int32*.

	* sunrpc/rpc_cmsg.c (xdr_callmsg), sunrpc/svc_authux.c: increment
	"buf" pointer by casting it to a char* first since a long* may be 8
 	bytes or more and oa->oa_length may be any multiple of 4.

	* sunrpc/rpc/xdr.h (IXDR_GET_LONG, IXDR_PUT_LONG): change casts to
 	u_int32_t (instead of u_long).

	* sunrpc/clnt_udp.c (clntudp_call): replaced sizeof(u_long) by 4
	since it really is testing for 32 bits.  Fixed casts to use
	u_int32 instead of u_long.
	* sunrpc/xdr_rec.c: Likewise.

	* sunrpc/clnt_tcp.c (clnttcp_call): replaced u_long by u_int32.
	* sunrpc/rpc/auth.h: Likewise.

	* limits.h (LONG_MAX, LONG_MIN, ULONG_MAX): use 64 bit values
	for Alpha.

Tue Mar 19 13:27:49 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	* sysdeps/i386/fpu/__math.h: New file.
	Contributed by John C. Bowman <bowman@hagar.ph.utexas.edu>.

Sun Mar 17 00:28:16 1996  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/posix/clock.c: Don't multiply the return value by
	CLOCKS_PER_SEC or CLK_TCK.

	* sysdeps/mach/hurd/getcwd.c: Fail with ENOENT if a parent directory
	scan finds no match.

	* posix/unistd.h (setpgrp): Declare no-arg version unless __FAVOR_BSD.
	* misc/bsd-compat.c (setpgrp): New function, two arg version.
	* sysdeps/stub/setpgid.c: Remove setpgrp alias.
	* sysdeps/mach/hurd/setpgid.c: Likewise.
	* sysdeps/unix/sysv/sysv4/setpgid.c: Likewise.
	* sysdeps/unix/common/syscalls.list (setpgid): Remove setpgrp alias.
	* sysdeps/unix/sysv/irix4/syscalls.list: Likewise.
	* sysdeps/unix/sysv/linux/setpgrp.c: Obsolete file removed.
	* posix/setpgrp.c (setpgrp): New file.
	* posix/Makefile (routines): Add setpgrp.

Tue Feb  6 12:46:29 1996  David Mosberger-Tang  <davidm@azstarnet.com>

	* libc-symbols.h (weak_alias, weak_symbol): added definitions
	for ECOFF (HAVE_ECOFF).
1996-03-19 20:21:54 +00:00

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/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
* This is derived from the Berkeley source:
* @(#)random.c 5.5 (Berkeley) 7/6/88
* It was reworked for the GNU C Library by Roland McGrath.
* Rewritten to use reentrent functions by Ulrich Drepper, 1995.
*/
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>
/* An improved random number generation package. In addition to the standard
rand()/srand() like interface, this package also has a special state info
interface. The initstate() routine is called with a seed, an array of
bytes, and a count of how many bytes are being passed in; this array is
then initialized to contain information for random number generation with
that much state information. Good sizes for the amount of state
information are 32, 64, 128, and 256 bytes. The state can be switched by
calling the setstate() function with the same array as was initiallized
with initstate(). By default, the package runs with 128 bytes of state
information and generates far better random numbers than a linear
congruential generator. If the amount of state information is less than
32 bytes, a simple linear congruential R.N.G. is used. Internally, the
state information is treated as an array of longs; the zeroeth element of
the array is the type of R.N.G. being used (small integer); the remainder
of the array is the state information for the R.N.G. Thus, 32 bytes of
state information will give 7 longs worth of state information, which will
allow a degree seven polynomial. (Note: The zeroeth word of state
information also has some other information stored in it; see setstate
for details). The random number generation technique is a linear feedback
shift register approach, employing trinomials (since there are fewer terms
to sum up that way). In this approach, the least significant bit of all
the numbers in the state table will act as a linear feedback shift register,
and will have period 2^deg - 1 (where deg is the degree of the polynomial
being used, assuming that the polynomial is irreducible and primitive).
The higher order bits will have longer periods, since their values are
also influenced by pseudo-random carries out of the lower bits. The
total period of the generator is approximately deg*(2**deg - 1); thus
doubling the amount of state information has a vast influence on the
period of the generator. Note: The deg*(2**deg - 1) is an approximation
only good for large deg, when the period of the shift register is the
dominant factor. With deg equal to seven, the period is actually much
longer than the 7*(2**7 - 1) predicted by this formula. */
/* For each of the currently supported random number generators, we have a
break value on the amount of state information (you need at least thi
bytes of state info to support this random number generator), a degree for
the polynomial (actually a trinomial) that the R.N.G. is based on, and
separation between the two lower order coefficients of the trinomial. */
/* Linear congruential. */
#define TYPE_0 0
#define BREAK_0 8
#define DEG_0 0
#define SEP_0 0
/* x**7 + x**3 + 1. */
#define TYPE_1 1
#define BREAK_1 32
#define DEG_1 7
#define SEP_1 3
/* x**15 + x + 1. */
#define TYPE_2 2
#define BREAK_2 64
#define DEG_2 15
#define SEP_2 1
/* x**31 + x**3 + 1. */
#define TYPE_3 3
#define BREAK_3 128
#define DEG_3 31
#define SEP_3 3
/* x**63 + x + 1. */
#define TYPE_4 4
#define BREAK_4 256
#define DEG_4 63
#define SEP_4 1
/* Array versions of the above information to make code run faster.
Relies on fact that TYPE_i == i. */
#define MAX_TYPES 5 /* Max number of types above. */
/* Initially, everything is set up as if from:
initstate(1, randtbl, 128);
Note that this initialization takes advantage of the fact that srandom
advances the front and rear pointers 10*rand_deg times, and hence the
rear pointer which starts at 0 will also end up at zero; thus the zeroeth
element of the state information, which contains info about the current
position of the rear pointer is just
(MAX_TYPES * (rptr - state)) + TYPE_3 == TYPE_3. */
static int32_t randtbl[DEG_3 + 1] =
{
TYPE_3,
-1726662223, 379960547, 1735697613, 1040273694, 1313901226,
1627687941, -179304937, -2073333483, 1780058412, -1989503057,
-615974602, 344556628, 939512070, -1249116260, 1507946756,
-812545463, 154635395, 1388815473, -1926676823, 525320961,
-1009028674, 968117788, -123449607, 1284210865, 435012392,
-2017506339, -911064859, -370259173, 1132637927, 1398500161,
-205601318,
};
static struct random_data unsafe_state =
{
/* FPTR and RPTR are two pointers into the state info, a front and a rear
pointer. These two pointers are always rand_sep places aparts, as they
cycle through the state information. (Yes, this does mean we could get
away with just one pointer, but the code for random is more efficient
this way). The pointers are left positioned as they would be from the call:
initstate(1, randtbl, 128);
(The position of the rear pointer, rptr, is really 0 (as explained above
in the initialization of randtbl) because the state table pointer is set
to point to randtbl[1] (as explained below).) */
fptr : &randtbl[SEP_3 + 1],
rptr : &randtbl[1],
/* The following things are the pointer to the state information table,
the type of the current generator, the degree of the current polynomial
being used, and the separation between the two pointers.
Note that for efficiency of random, we remember the first location of
the state information, not the zeroeth. Hence it is valid to access
state[-1], which is used to store the type of the R.N.G.
Also, we remember the last location, since this is more efficient than
indexing every time to find the address of the last element to see if
the front and rear pointers have wrapped. */
state : &randtbl[1],
rand_type : TYPE_3,
rand_deg : DEG_3,
rand_sep : SEP_3,
end_ptr : &randtbl[sizeof (randtbl) / sizeof (randtbl[0])]
};
/* Initialize the random number generator based on the given seed. If the
type is the trivial no-state-information type, just remember the seed.
Otherwise, initializes state[] based on the given "seed" via a linear
congruential generator. Then, the pointers are set to known locations
that are exactly rand_sep places apart. Lastly, it cycles the state
information a given number of times to get rid of any initial dependencies
introduced by the L.C.R.N.G. Note that the initialization of randtbl[]
for default usage relies on values produced by this routine. */
void
__srandom (x)
unsigned int x;
{
(void) __srandom_r (x, &unsafe_state);
}
weak_alias (__srandom, srandom)
weak_alias (__srandom, srand)
/* Initialize the state information in the given array of N bytes for
future random number generation. Based on the number of bytes we
are given, and the break values for the different R.N.G.'s, we choose
the best (largest) one we can and set things up for it. srandom is
then called to initialize the state information. Note that on return
from srandom, we set state[-1] to be the type multiplexed with the current
value of the rear pointer; this is so successive calls to initstate won't
lose this information and will be able to restart with setstate.
Note: The first thing we do is save the current state, if any, just like
setstate so that it doesn't matter when initstate is called.
Returns a pointer to the old state. */
void *
__initstate (seed, arg_state, n)
unsigned int seed;
void *arg_state;
size_t n;
{
void *ostate = (void *) &unsafe_state.state[-1];
__initstate_r (seed, arg_state, n, &unsafe_state);
return ostate;
}
weak_alias (__initstate, initstate)
/* Restore the state from the given state array.
Note: It is important that we also remember the locations of the pointers
in the current state information, and restore the locations of the pointers
from the old state information. This is done by multiplexing the pointer
location into the zeroeth word of the state information. Note that due
to the order in which things are done, it is OK to call setstate with the
same state as the current state
Returns a pointer to the old state information. */
void *
__setstate (arg_state)
void *arg_state;
{
void *ostate = (void *) &unsafe_state.state[-1];
if (__setstate_r (arg_state, &unsafe_state) < 0)
return NULL;
return ostate;
}
weak_alias (__setstate, setstate)
/* If we are using the trivial TYPE_0 R.N.G., just do the old linear
congruential bit. Otherwise, we do our fancy trinomial stuff, which is the
same in all ther other cases due to all the global variables that have been
set up. The basic operation is to add the number at the rear pointer into
the one at the front pointer. Then both pointers are advanced to the next
location cyclically in the table. The value returned is the sum generated,
reduced to 31 bits by throwing away the "least random" low bit.
Note: The code takes advantage of the fact that both the front and
rear pointers can't wrap on the same call by not testing the rear
pointer if the front one has wrapped. Returns a 31-bit random number. */
int
__random ()
{
int32_t retval;
(void) __random_r (&unsafe_state, &retval);
return retval;
}
weak_alias (__random, random)