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bugs with count_leading_zeros and gmp-4.0
From: |
Nathalie Revol |
Subject: |
bugs with count_leading_zeros and gmp-4.0 |
Date: |
Fri, 21 Dec 2001 18:47:21 +0100 (MET) |
Hello
we (me by chance and Paul by analyzing "my" bug) encountered a problem
with count_leading_zeros when applied to 42 (= 101010 in binary),
cf. C program below.
The result should be 26 = 32-6 and it is 27:
pastaga% gcc -I. -L.libs toto.c -lgmp (in the gmp-4.0 directory)
pastaga% ./a.out
k=27
Regards
Nathalie
Some info on my machine and my compiler:
pastaga% uname -a
SunOS pastaga 5.8 Generic sun4u sparc SUNW,Ultra-5_10
pastaga% gcc -v
Reading specs from /usr/local/lib/gcc-lib/sparc-sun-solaris2.6/2.95.2/specs
gcc version 2.95.2 19991024 (release)
pastaga% isainfo
sparcv9 sparc
pastaga% prtconf -vp
System Configuration: Sun Microsystems sun4u
Memory size: 128 Megabytes
System Peripherals (PROM Nodes):
[...]
Node 0xf006cd5c
manufacturer#: 00000017
implementation#: 00000012
mask#: 00000091
sparc-version: 00000009
ecache-associativity: 00000001
ecache-line-size: 00000040
ecache-size: 00040000
#dtlb-entries: 00000040
dcache-associativity: 00000001
dcache-line-size: 00000020
dcache-size: 00004000
#itlb-entries: 00000040
icache-associativity: 00000002
icache-line-size: 00000020
icache-size: 00004000
upa-portid: 00000000
clock-frequency: 15752a00
reg: 000001c0.00000000.00000000.00000008
device_type: 'cpu'
name: 'SUNW,UltraSPARC-IIi'
---------------------------------------------------------------------------
Nathalie REVOL
LIP - Projet INRIA Arenaire tel : (33) 4-72-72-86-42
Ecole Normale Superieure de Lyon Fax : (33) 4-72-72-80-80
69364 Lyon Cedex 07 address@hidden
FRANCE http://www.ens-lyon.fr/~nrevol
---------------------------------------------------------------------------
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
main()
{
int k;
mp_limb_t c;
c = (mp_limb_t) 42;
count_leading_zeros(k, c);
printf("k=%d\n", k);
}
- bugs with count_leading_zeros and gmp-4.0,
Nathalie Revol <=