This is the source code for nrand48 from gnuwin32 libgw32c
long int nrand48 (xsubi) unsigned short int xsubi[3];
{
long int result;
(void) __nrand48_r (xsubi, &__libc_drand48_data, &result);
return result;
}
// long int nrand48 (xsubi) unsigned short int xsubi[3];
What does the 'unsigned short int xsubi[3];' part mean after '(xsubi)' ?
The prototype in stdlib.h from the binaries is: (for some reason stdlib.h
was not in source distribution ?)
extern long int nrand48 (unsigned short int __xsubi[3]) __THROW;
So at first sight I would guess it has to do with throwing exceptions... but
now that I look at it again it I think it's the type for xsubi.
The original looks really weird:
1. long int nrand48 (xsubi) unsigned short int xsubi[3];
Isn't that supposed to look like this:
2. long int nrand48 (unsigned short int xsubi[3] );
Why did they write it as 1. ?
Is that just their preferred way of writing it down... or does it have some
sort of functionality ?
The prototype then again looks like 2. !? huh ?! :)
Euhm... Could this be a case of wacky c programmers ? eh.
Bye,
Skybuck. 10 2136
Skybuck Flying <no****@hotmail.com> wrote: This is the source code for nrand48 from gnuwin32 libgw32c
long int nrand48 (xsubi) unsigned short int xsubi[3]; { long int result;
(void) __nrand48_r (xsubi, &__libc_drand48_data, &result);
return result; }
// long int nrand48 (xsubi) unsigned short int xsubi[3];
What does the 'unsigned short int xsubi[3];' part mean after '(xsubi)' ?
That's the very old way function definitions where written back in
the K&R days when there wasn't a C standard. It's basically equiva-
lent to
long int nrand48( unsigned short int xsubi[ 3 ] )
In code dating back from that time you typically had function definitions
starting with
my_func( a, b, c )
int a,
char *b,
unsigned short c
{
which nowadays would be written as
int my_func( int a, char *b, unsigned short c )
{
The prototype in stdlib.h from the binaries is: (for some reason stdlib.h was not in source distribution ?)
extern long int nrand48 (unsigned short int __xsubi[3]) __THROW;
So at first sight I would guess it has to do with throwing exceptions... but now that I look at it again it I think it's the type for xsubi.
Better don't look at the header files unless you have very good reasons
to (or just out of curiosity). Lots of system-dependend magic is going
on there.
Regards, Jens
--
\ Jens Thoms Toerring ___ Je***********@physik.fu-berlin.de
\__________________________ http://www.toerring.de
<Je***********@physik.fu-berlin.de> wrote in message
news:2l************@uni-berlin.de... Skybuck Flying <no****@hotmail.com> wrote: This is the source code for nrand48 from gnuwin32 libgw32c
long int nrand48 (xsubi) unsigned short int xsubi[3]; { long int result;
(void) __nrand48_r (xsubi, &__libc_drand48_data, &result);
return result; }
// long int nrand48 (xsubi) unsigned short int xsubi[3];
What does the 'unsigned short int xsubi[3];' part mean after '(xsubi)' ?
That's the very old way function definitions where written back in the K&R days when there wasn't a C standard. It's basically equiva- lent to
long int nrand48( unsigned short int xsubi[ 3 ] )
In code dating back from that time you typically had function definitions starting with
my_func( a, b, c ) int a, char *b, unsigned short c {
which nowadays would be written as
int my_func( int a, char *b, unsigned short c ) {
Yes, I was starting to think that C was a really #^#@$ language :)
Visual C/C++ 6.0 doesn't the support the old way...
<<<--- sigh --->>>
So now I have to re-write it all...
Fortunately for me... It's only a little bit of code... and fortunately I
rarely program in C :P =D
Thx for the description... Lol... it must be painfull to code in C :D
Bye,
Skybuck.
"Skybuck Flying" <no****@hotmail.com> wrote: <Je***********@physik.fu-berlin.de> wrote in message news:2l************@uni-berlin.de... That's the very old way function definitions where written back in the K&R days when there wasn't a C standard.
Visual C/C++ 6.0 doesn't the support the old way...
Then it's not a C compiler. Are you sure you're not pretending to
compile C++?
Thx for the description... Lol... it must be painfull to code in C :D
Certainly not. It's a lot less painful if you actually learn to program.
Richard
Finally...
A working nrand48() :)
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <float.h>
//typedef unsigned long long uint64_t
typedef signed __int8 sint8;
typedef unsigned __int8 uint8;
typedef signed __int16 sint16;
typedef unsigned __int16 uint16;
typedef signed __int32 sint32;
typedef unsigned __int32 uint32;
typedef signed __int64 sint64;
typedef unsigned __int64 uint64;
/* Data structure for communication with thread safe versions. This
type is to be regarded as opaque. It's only exported because users
have to allocate objects of this type. */
struct drand48_data
{
unsigned short int __x[3]; /* Current state. */
unsigned short int __old_x[3]; /* Old state. */
unsigned short int __c; /* Additive const. in congruential formula. */
unsigned short int __init; /* Flag for initializing. */
uint64 __a; /* Factor in congruential formula. */
};
/* Global state for non-reentrant functions. */
struct drand48_data __libc_drand48_data;
int __drand48_iterate ( unsigned short int xsubi[3], struct drand48_data
*buffer )
{
uint64 X;
uint64 result;
/* Initialize buffer, if not yet done. */
// built in bullshit removed
// if (__builtin_expect (!buffer->__init, 0))
if (buffer->__init == 0)
{
buffer->__a = 0x5deece66du;
buffer->__c = 0xb;
buffer->__init = 1;
}
/* Do the real work. We choose a data type which contains at least
48 bits. Because we compute the modulus it does not care how
many bits really are computed. */
X = (uint64) xsubi[2] << 32 | (uint32) xsubi[1] << 16 | xsubi[0];
result = X * buffer->__a + buffer->__c;
xsubi[0] = result & 0xffff;
xsubi[1] = (result >> 16) & 0xffff;
xsubi[2] = (result >> 32) & 0xffff;
return 0;
}
int __nrand48_r (
unsigned short int xsubi[3],
struct drand48_data *buffer,
long int *result )
{
/* Compute next state. */
if (__drand48_iterate (xsubi, buffer) < 0)
{
return -1;
}
/* Store the result. */
if (sizeof (unsigned short int) == 2)
{
*result = xsubi[2] << 15 | xsubi[1] >> 1;
}
else
{
*result = xsubi[2] >> 1;
}
return 0;
}
long int nrand48 (unsigned short int xsubi[3])
{
long int result;
(void) __nrand48_r (xsubi, &__libc_drand48_data, &result);
return result;
}
int main()
{
unsigned short state48[3];
printf("%d \n", nrand48(state48) );
return 0;
}
Compiling...
Main.cpp
C:\C TESTEN\TestNRand48\Main.cpp(59) : warning C4244: '=' : conversion from
'unsigned __int64' to 'unsigned short', possible loss of data
C:\C TESTEN\TestNRand48\Main.cpp(60) : warning C4244: '=' : conversion from
'unsigned __int64' to 'unsigned short', possible loss of data
C:\C TESTEN\TestNRand48\Main.cpp(61) : warning C4244: '=' : conversion from
'unsigned __int64' to 'unsigned short', possible loss of data
Linking...
TestNRand48.exe - 0 error(s), 3 warning(s)
Except these three lines produce a warning in visual c 6
xsubi[0] = result & 0xffff;
xsubi[1] = (result >> 16) & 0xffff;
xsubi[2] = (result >> 32) & 0xffff;
Seeing the 0xffff I can conclude that unsigned short must be a unsigned 16
bit integer.
So these warnings can probably be safely surpressed >D by using:
xsubi[0] = uint16( result & 0xffff );
xsubi[1] = uint16( (result >> 16) & 0xffff );
xsubi[2] = uint16( (result >> 32) & 0xffff );
Jip..
That did the trick.
Bye,
Skybuck
P.S.: Take care ;)
"Skybuck Flying" <no****@hotmail.com> wrote: typedef unsigned __int16 uint16;
[ Snip loads of code including lots of non-standard types and
identifiers in the implementation's namespace. ]
So these warnings can probably be safely surpressed >D by using:
xsubi[0] = uint16( result & 0xffff );
uint16 is a type, not a function. Are you _very_ sure you're not
compiling C++?
Richard
In article <2l************@uni-berlin.de>,
<Je***********@physik.fu-berlin.de> wrote: In code dating back from that time you typically had function definitions starting with
my_func( a, b, c ) int a, char *b, unsigned short c {
No. We had function staring like this:
my_func( a, b, c )
int a;
char *b;
unsigned short c;
{
--
Göran Larsson http://www.mitt-eget.com/
"Richard Bos" <rl*@hoekstra-uitgeverij.nl> wrote in message
news:40****************@news.individual.net... "Skybuck Flying" <no****@hotmail.com> wrote:
typedef unsigned __int16 uint16;
[ Snip loads of code including lots of non-standard types and identifiers in the implementation's namespace. ]
So these warnings can probably be safely surpressed >D by using:
xsubi[0] = uint16( result & 0xffff );
uint16 is a type, not a function. Are you _very_ sure you're not compiling C++?
Hmm when splitting it up into multiple files it indeed produced an error
I think the correct typecast code to use is:
Not:
xsubi[0] = uint16( result & 0xffff );
Butttt:
xsubi[0] = (uint16) ( result & 0xffff );
:DD
Skybuck.
On Wed, 7 Jul 2004 15:15:44 +0200, "Skybuck Flying"
<no****@hotmail.com> wrote: <Je***********@physik.fu-berlin.de> wrote in message news:2l************@uni-berlin.de... Skybuck Flying <no****@hotmail.com> wrote:
Thx for the description... Lol... it must be painfull to code in C :D
We're all sadists in this manner :)
--
aib
ISP e-mail accounts are good for receiving spam.
Skybuck Flying wrote:
[... old-vs-new function definitions ...] Visual C/C++ 6.0 doesn't the support the old way...
<<<--- sigh --->>>
So now I have to re-write it all...
[...]
Excuse me? I have a program with several hundred thousand line of code
and 99.9% of the functions are coded "the old way". (We support platforms
that still don't allow "the new way".) It compiles just fine under VC6.0.
--
+-------------------------+--------------------+-----------------------------+
| Kenneth J. Brody | www.hvcomputer.com | |
| kenbrody at spamcop.net | www.fptech.com | #include <std_disclaimer.h> |
+-------------------------+--------------------+-----------------------------+
On Thu, 8 Jul 2004, Orhan Kavrakoglu wrote:
OK>On Wed, 7 Jul 2004 15:15:44 +0200, "Skybuck Flying"
OK><no****@hotmail.com> wrote:
OK>
OK>>
OK>><Je***********@physik.fu-berlin.de> wrote in message
OK>>news:2l************@uni-berlin.de...
OK>>> Skybuck Flying <no****@hotmail.com> wrote:
OK>
OK>>Thx for the description... Lol... it must be painfull to code in C :D
OK>>
OK>
OK>We're all sadists in this manner :)
And he probably hasn't see Intercal yet.
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