Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
| Newsgroups | comp.lang.c |
|---|---|
| Subject | Re: Arithmetic overflow checking, not so hard after all |
| References | (9 earlier) <ivh7ub$qtp$1@dont-email.me> <overflow-20110712151620@ram.dialup.fu-berlin.de> <ivhskb$1gp$1@dont-email.me> <1boc0zcugu.fsf@snowball.wb.pfeifferfamily.net> <lny603tmop.fsf@nuthaus.mib.org> |
| From | "Greg A. Woods" <woods@robohack.org> |
| Message-ID | <87d3hebx3z.fsf_-_@once.weird.com> (permalink) |
| Date | 2011-07-12 21:52 -0700 |
Keith Thompson <kst-u@mib.org> writes:
>
> But detecting the overflow in the first place can be *very* tricky.
Assuming your code is too complex or performance sensitive to use a
compiler that can do the checking for you (e.g. maybe with Clang's
"-ftrapv" -- see my comments below), it's reasonlyb easy to reliably do
the checks yourself, assuming you understand your target platform.
Attached is some test code I wrote quite a long time ago for checking
compilers and such. It uses techniques I found from various sources to
demonstrate the possibilities of reliable integer overflow and
underflow detection for addition and subtraction, respectively.
I think I've covered testing each technique for most of the corner &
edge cases you have to watch out for, but I can't be certain.
I just re-ran it with some newer versions of GCC though and I see that
'-ftrapv' doesn't seem to work at all any more. They broke it bad, and
haven't got around to fixing it yet. See the comments in the code below.
Half-hearted apologies to anyone stuck with an 80-column terminal. Join
the modern age and get a wider screen! :-)
Greg A. Woods
RoboHack
<woods@robohack.ca> living on the edge http://www.robohack.ca/
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
/*
* NOTES about C implementations vs. integer overflow detection:
*
* GCC has '-ftrapv' which (in some versions) replaces integer arithmetic
* operators with calls to libgcc wrapper functions which (assuming
* two's-complement signed integer arithmetic implementstions) will do overflow
* checks (usually post-condition wrap-around checks) and call abort() if
* there's an overflow detected in the operation.
*
* Unfortunately using GCC-4.1.2's '-ftrapv' in combination with any
* optimization (i.e. '-O1' or greater) then the compiler will apparently
* generate code which will purposefuly optimize away the libgcc internal calls
* for (at least) addition operations. The tests below will still detect the
* overflows at runtime, and we know these tests are never optimized away
* because we check that they work correctly for known non-overflowing values.
* This is a GCC bug.
*
* Even more recent versions of GCC suffer worse:
*
* '-ftrapv' has no affect on Mac OS X (10.6.8 w/ gcc 4.2.1) (not in manpage)
*
* '-ftrapv' has no affect on FreeBSD 8.x w/ gcc 4.2.1 either (is documented)
*
* And as of last check, it's still a noted, open, bug:
*
* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35412
*
* However some discussions on some GCC mailing lists suggest this is too
* broken to fix as-is. Back in 2008 it was suggested it be deprecated for 4.4
* and re-implemented properly using GIMPLE, whatever that is.
*
* Some other work done on this issue:
*
* http://repository.cmu.edu/cgi/viewcontent.cgi?article=1017&context=ece
*
* Clang does support '-ftrapv', and it works even with -O3.
*
* BTW, if you do use '-ftrapv' you could add a signal handler for SIGABRT, or
* re-define the abort() function, and then get signalled/called for every test
* where overflow/underflow is detected.
*
* Someday C may have "as-if infinitely ranging integers".....
*/
/*
* WARNING: when testing this kind of stuff one must be careful not to give
* away the secret to the optimizer, else it's certain to just elide your code.
* Here we either use a system call to make the compiler uncertain about what
* value will be used, or (with the following #define) we enable input options
* for the user to supply the values, giving our suggestion as a simplistic
* automated Turing test to out-smart the compiler.
*/
#if 1
#define USE_TIME_TO_INIT /* defined.... */
#endif
void unsigned_int_add_ovf(unsigned int, unsigned int);
void unsigned_int_sub_undf(unsigned int, unsigned int);
void signed_int_add_ovf_1(signed int, signed int);
void signed_int_add_ovf_2(signed int, signed int);
void signed_int_add_ovf_3(signed int, signed int);
void signed_int_add_ovf_mot(signed int, signed int);
void signed_int_add_ovf_cert_2s(signed int, signed int);
void signed_int_add_ovf_cert_any(signed int, signed int);
void signed_int_sub_undf_3(signed int, signed int);
void signed_int_sub_undf_mot(signed int, signed int);
int main(void);
int
main()
{
unsigned int ufoo;
unsigned int ubar;
signed int foo;
signed int bar;
int high_int_bit = (1 << ((int) (sizeof(int) * CHAR_BIT) - 1));
/*
* note: this entire "if" trivially gets optimized away with -O1
*/
if (high_int_bit != INT_MIN) {
printf("*** high bit expression says INT_MIN is busted! (INT_MIN=0x%x)\n", INT_MIN);
}
printf("\nTesting unsigned integer OK....\n\n");
#ifdef USE_TIME_TO_INIT
ufoo = (time((time_t) NULL) < 0) ? 42 : 1;
ubar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter a 1: ");
fscanf(stdin, "%u", &ufoo);
printf("got %u\n\n", ufoo);
printf("Enter a 1: ");
fscanf(stdin, "%u", &ubar);
printf("got %u\n\n", ubar);
#endif
unsigned_int_add_ovf(ufoo, ubar); /* UINT_MAX + 1 */
#ifdef USE_TIME_TO_INIT
ufoo = (time((time_t) NULL) < 0) ? 42 : (UINT_MAX - 1);
#else
printf("Enter %d: ", (UINT_MAX - 1));
fscanf(stdin, "%u", &ufoo);
printf("got %u\n\n", ufoo);
#endif
unsigned_int_add_ovf(ufoo, ubar); /* (UINT_MAX-1) + 1 */
printf("\nTesting unsigned integer overflow detection....\n\n");
#ifdef USE_TIME_TO_INIT
ufoo = (time((time_t) NULL) < 0) ? 42 : UINT_MAX;
ubar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter %u: ", UINT_MAX);
fscanf(stdin, "%u", &ufoo);
printf("got %u\n\n", ufoo);
printf("Enter a 1: ");
fscanf(stdin, "%u", &ubar);
printf("got %u\n\n", ubar);
#endif
unsigned_int_add_ovf(ufoo, ubar); /* UINT_MAX + 1 */
#ifdef USE_TIME_TO_INIT
ubar = (time((time_t) NULL) < 0) ? 42 : UINT_MAX;
#else
printf("Enter %u: ", UINT_MAX);
fscanf(stdin, "%u", &ubar);
printf("got %u\n\n", ubar);
#endif
unsigned_int_add_ovf(ufoo, ubar); /* UINT_MAX + UINT_MAX */
#ifdef USE_TIME_TO_INIT
ufoo = (time((time_t) NULL) < 0) ? 42 : 0;
ubar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter a 0: ");
fscanf(stdin, "%u", &ufoo);
printf("got %u\n\n", ufoo);
printf("Enter a 1: ");
fscanf(stdin, "%u", &ubar);
printf("got %u\n\n", ubar);
#endif
unsigned_int_sub_undf(ufoo, ubar); /* 0 - 1 */
#ifdef USE_TIME_TO_INIT
ubar = (time((time_t) NULL) < 0) ? 42 : UINT_MAX;
#else
printf("Enter %u: ", UINT_MAX);
fscanf(stdin, "%u", &ubar);
printf("got %u\n\n", ubar);
#endif
unsigned_int_sub_undf(ufoo, ubar); /* 0 - UINT_MAX */
printf("\nTesting signed integer OK....\n\n");
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : 1;
bar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter a 1: ");
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
printf("Enter a 1: ");
fscanf(stdin, "%d", &bar);
printf("got %d\n\n", bar);
#endif
signed_int_add_ovf_1(foo, bar); /* INT_MAX + 1 */
signed_int_add_ovf_2(foo, bar);
signed_int_add_ovf_3(foo, bar);
signed_int_add_ovf_mot(foo, bar);
signed_int_add_ovf_cert_2s(foo, bar);
signed_int_add_ovf_cert_any(foo, bar);
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : (INT_MAX - 1);
#else
printf("Enter %d: ", (INT_MAX - 1));
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
#endif
signed_int_add_ovf_1(foo, bar); /* (INT_MAX-1) + 1 */
signed_int_add_ovf_2(foo, bar);
signed_int_add_ovf_3(foo, bar);
signed_int_add_ovf_mot(foo, bar);
signed_int_add_ovf_cert_2s(foo, bar);
signed_int_add_ovf_cert_any(foo, bar);
printf("\nTesting signed integer addition overflow detection....\n\n");
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : INT_MAX;
bar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter %d: ", INT_MAX);
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
printf("Enter a 1: ");
fscanf(stdin, "%d", &bar);
printf("got %d\n\n", bar);
#endif
signed_int_add_ovf_1(foo, bar);
signed_int_add_ovf_2(foo, bar);
signed_int_add_ovf_3(foo, bar);
signed_int_add_ovf_mot(foo, bar);
signed_int_add_ovf_cert_2s(foo, bar);
signed_int_add_ovf_cert_any(foo, bar);
#ifdef USE_TIME_TO_INIT
bar = (time((time_t) NULL) < 0) ? 42 : INT_MAX;
#else
printf("Enter %d: ", INT_MAX);
fscanf(stdin, "%d", &bar);
printf("got %d\n\n", bar);
#endif
signed_int_add_ovf_1(foo, bar);
signed_int_add_ovf_2(foo, bar);
signed_int_add_ovf_3(foo, bar);
signed_int_add_ovf_mot(foo, bar);
signed_int_add_ovf_cert_2s(foo, bar);
signed_int_add_ovf_cert_any(foo, bar);
printf("\nTesting signed integer subtraction OK....\n\n");
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : 1;
bar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter a 1: ");
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
printf("Enter a 1: ");
fscanf(stdin, "%d", &bar);
printf("got %d\n\n", bar);
#endif
signed_int_sub_undf_3(foo, bar);
signed_int_sub_undf_mot(foo, bar);
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : 0;
#else
printf("Enter a 0: ");
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
#endif
signed_int_sub_undf_3(foo, bar);
signed_int_sub_undf_mot(foo, bar);
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : (INT_MIN + 1);
#else
printf("Enter %d: ", (INT_MIN + 1));
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
#endif
signed_int_sub_undf_3(foo, bar);
signed_int_sub_undf_mot(foo, bar);
printf("\nTesting signed integer subtraction underflow detection....\n\n");
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : INT_MIN;
bar = (time((time_t) NULL) < 0) ? 42 : 1;
#else
printf("Enter %d: ", INT_MIN);
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
printf("Enter a 1: ");
fscanf(stdin, "%d", &bar);
printf("got %d\n\n", bar);
#endif
signed_int_sub_undf_3(foo, bar);
signed_int_sub_undf_mot(foo, bar);
#ifdef USE_TIME_TO_INIT
foo = (time((time_t) NULL) < 0) ? 42 : INT_MIN;
bar = (time((time_t) NULL) < 0) ? 42 : INT_MAX;
#else
printf("Enter %d: ", INT_MIN);
fscanf(stdin, "%d", &foo);
printf("got %d\n\n", foo);
printf("Enter %d: ", INT_MAX);
fscanf(stdin, "%d", &bar);
printf("got %d\n\n", bar);
#endif
signed_int_sub_undf_3(foo, bar);
signed_int_sub_undf_mot(foo, bar);
exit(0);
}
void
unsigned_int_add_ovf(ufoo, ubar)
unsigned int ufoo; /* = UINT_MAX */
unsigned int ubar; /* = 1 */
{
unsigned int usum;
/*
* the simplest (and most portable) case is for addition of unsigned
* integers -- just check that the result is not less than either of
* the operands:
*
* (you should be using unsigned ints for array subscripts anyway!)
*/
usum = ufoo + ubar;
if (usum < ufoo || usum < ubar) {
printf("*** unsigned integer addition overflow: %u + %u = %u!\n", ufoo, ubar, usum);
} else {
printf("unsigned integer addition OK: %u + %u = %u\n", ufoo, ubar, usum);
}
}
void
unsigned_int_sub_undf(ufoo, ubar)
unsigned int ufoo; /* = 0 */
unsigned int ubar; /* = UINT_MAX || 1 */
{
unsigned int udiff;
/*
* similarly for subtraction -- just check that the result is not
* greater than either of the operands:
*/
udiff = ufoo - ubar;
if (udiff > ufoo || udiff > ubar) {
printf("*** unsigned integer subtraction underflow: %u - %u = %u!\n", ufoo, ubar, udiff);
} else {
printf("unsigned integer subtraction OK: %u - %u = %u\n", ufoo, ubar, udiff);
}
}
void
signed_int_add_ovf_1(foo, bar)
signed int foo;
signed int bar;
{
signed int sum;
/*
* For signed integers on two's-compliment systems:
*
* When using operators such as '+' and '-', in which both operands
* have like signs, a change of sign in the result indicates an
* overflow condition.
*
* Note that if the signs of the operands are different then of course
* an overflow or underflow is impossible.
*/
sum = foo + bar;
if ((foo >= 0 && bar <= 0) ||
(foo <= 0 && bar >= 0)) {
printf("signed 2's-compliment integer addition 1 OK: %d + %d = %d\n", foo, bar, sum);
} else if ((foo > 0 && sum < 0) ||
(foo < 0 && sum > 0)) {
printf("*** signed 2's-compliment integer addition overflow 1: %d + %d = %d!\n", foo, bar, sum);
} else {
printf("signed 2's-compliment integer addition 1 OK: %d + %d = %d\n", foo, bar, sum);
}
}
void
signed_int_add_ovf_2(foo, bar)
signed int foo;
signed int bar;
{
signed int sum;
/*
* perhaps even simpler than the sign-change check though for
* 2's-complement systems is this simple magnitude check of one operand
* against the result based on whether the other operand is positive or
* not (from GCC's "-ftrapv" runtime):
*
* NOTE: This is probably the least expensive post-condition check!
*/
sum = foo + bar;
if ((foo >= 0) ? (sum < bar) : (sum > bar)) {
printf("*** signed 2's-complement integer addition overflow 2: %d + %d = %d!\n", foo, bar, sum);
} else {
printf("signed 2's-complement integer addition 2 OK: %d + %d = %d\n", foo, bar, sum);
}
}
void
signed_int_add_ovf_3(foo, bar)
signed int foo;
signed int bar;
{
signed int sum;
/*
* from Autoconf's manual, a tranformed variant of the above expression
*/
sum = foo + bar;
if ((sum < bar) != (foo < 0)) {
printf("*** signed 2's-complement integer addition overflow 3: %d + %d = %d!\n", foo, bar, sum);
} else {
printf("signed 2's-complement integer addition 3 OK: %d + %d = %d\n", foo, bar, sum);
}
}
void
signed_int_add_ovf_mot(foo, bar)
signed int foo;
signed int bar;
{
signed int sum;
/*
* without regard to the sign of the operands we can also use the
* following on two's-complement systems (Apparently from Motorola's
* documented scheme for setting the overflow bit in MC68k family).
*/
sum = foo + bar;
if (((foo & bar & ~sum) | (~foo & ~bar & sum)) < 0) {
printf("*** safe & simple signed 2's-complement integer addition overflow: %d + %d = %d!\n", foo, bar, sum);
} else {
printf("safe & simple signed signed 2's-complement integer addition OK: %d + %d = %d\n", foo, bar, sum);
}
}
void
signed_int_add_ovf_cert_2s(foo, bar)
signed int foo;
signed int bar;
{
signed int sum;
/*
* The CERT secure coding page shows an even more complex version (I've
* replaced a complex static expression with INT_MIN) of this still
* very complex and much more expensive (especially on RISC CPUs)
* solution for testing for potential integer overflow when adding two
* integer values when the host uses a two's-complement representation
* for integers:
*/
if (((foo^bar) | (((foo^(~(foo^bar) & INT_MIN)) + bar)^bar)) >= 0) {
sum = foo + bar;
printf("*** expensive pre-condition signed 2's-complement integer addition overflow: %d + %d = %d!\n", foo, bar, sum);
} else {
sum = foo + bar;
printf("expensive pre-condition signed 2's-complement integer addition OK: %d + %d = %d\n", foo, bar, sum);
}
}
void
signed_int_add_ovf_cert_any(foo, bar)
signed int foo;
signed int bar;
{
signed int sum;
/*
* The CERT secure coding page goes on to show another equally (or even
* more) expensive solution for testing for potential integer overflow
* when adding two integer values regardless of what binary
* representation the host uses for integers:
*/
if ((foo > 0 && bar > 0 && foo > (INT_MAX - bar)) ||
(foo < 0 && bar < 0 && foo < (INT_MIN - bar))) {
sum = foo + bar;
printf("*** expensive pre-conditioned signed integer addition overflow: %d + %d = %d!\n", foo, bar, sum);
} else {
sum = foo + bar;
printf("expensive pre-condition signed integer addition OK: %d + %d = %d\n", foo, bar, sum);
}
}
void
signed_int_sub_undf_3(foo, bar)
signed int foo;
signed int bar;
{
signed int diff;
/*
* again from libgcc:
*
* NOTE: This is probably the least expensive post-condition check!
*/
diff = foo - bar;
if ((bar >= 0) ? (diff > foo) : (diff < foo)) {
printf("*** signed 2's-complement integer subtraction underflow 3: %d - %d = %d!\n", foo, bar, diff);
} else {
printf("signed 2's-complement integer subtraction OK 3: %d - %d = %d\n", foo, bar, diff);
}
}
void
signed_int_sub_undf_mot(foo, bar)
signed int foo;
signed int bar;
{
signed int diff;
/*
* again from Motorola:
*/
diff = foo - bar;
if (((foo & ~bar & ~diff) | (~foo & bar & diff)) < 0) {
printf("*** safe & simple signed 2's-complement integer subtraction overflow: %d - %d = %d!\n", foo, bar, diff);
} else {
printf("safe & simple signed signed 2's-complement integer subtraction OK: %d - %d = %d\n", foo, bar, diff);
}
}
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-10 01:47 -0700
Re: Arithmetic overflow checking China Blue Dolls <chine.bleu@yahoo.com> - 2011-07-10 02:47 -0700
Re: Arithmetic overflow checking pete <pfiland@mindspring.com> - 2011-07-10 06:04 -0400
Re: Arithmetic overflow checking China Blue Dolls <chine.bleu@yahoo.com> - 2011-07-10 03:29 -0700
Re: Arithmetic overflow checking Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-07-10 20:52 +0300
Re: Arithmetic overflow checking pete <pfiland@mindspring.com> - 2011-07-10 23:29 -0400
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-10 04:44 -0700
Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-12 11:33 +0100
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 04:17 -0700
Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-12 12:33 +0100
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 05:24 -0700
Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-12 21:45 -0400
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-12 05:25 -0700
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 10:21 -0700
Re: Arithmetic overflow checking Thomas Boell <tboell@domain.invalid> - 2011-07-12 22:39 +0200
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 14:15 -0700
Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-12 14:18 -0700
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 23:54 -0700
Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-12 19:14 +0100
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-13 00:20 -0700
Re: Arithmetic overflow checking markspace <-@.> - 2011-07-12 09:26 -0700
Re: Arithmetic overflow checking Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-07-12 10:52 -0600
Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-12 10:48 -0700
Re: Arithmetic overflow checking Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-07-12 12:36 -0600
Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-12 12:16 -0700
Re: Arithmetic overflow checking Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-07-12 14:09 -0600
Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-12 14:16 -0700
Re: Arithmetic overflow checking, not so hard after all "Greg A. Woods" <woods@robohack.org> - 2011-07-12 21:52 -0700
Re: Arithmetic overflow checking, not so hard after all Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-07-13 12:50 +0100
Re: Arithmetic overflow checking, not so hard after all "Greg A. Woods" <woods@robohack.org> - 2011-07-13 11:10 -0700
Re: Arithmetic overflow checking, not so hard after all Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-07-14 01:34 +0100
Re: Arithmetic overflow checking, not so hard after all "Greg A. Woods" <woods@robohack.org> - 2011-07-19 17:10 -0700
Re: Arithmetic overflow checking, not so hard after all Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-07-19 20:47 -0600
Re: Arithmetic overflow checking, not so hard after all Keith Thompson <kst-u@mib.org> - 2011-07-19 20:23 -0700
Re: Arithmetic overflow checking, not so hard after all Todd Carnes <toddcarnes@gmail.com> - 2011-07-20 03:48 +0000
Re: Arithmetic overflow checking, not so hard after all Keith Thompson <kst-u@mib.org> - 2011-07-13 09:27 -0700
Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-14 23:55 -0500
Re: Arithmetic overflow checking Martin Gregorie <martin@address-in-sig.invalid> - 2011-07-12 16:54 +0000
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 11:35 -0700
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 10:13 -0700
Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-12 21:53 -0400
Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-14 23:41 -0500
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-15 10:56 -0700
Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-15 21:27 -0500
Re: Arithmetic overflow checking bugbear <bugbear@trim_papermule.co.uk_trim> - 2011-07-20 09:22 +0100
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-20 10:51 -0700
Re: Arithmetic overflow checking gordonb.3urm7@burditt.org (Gordon Burditt) - 2011-07-20 15:39 -0500
Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-21 12:12 +0100
Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-10 09:28 -0400
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-10 06:52 -0700
Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-10 14:47 -0700
Re: Arithmetic overflow checking gordonb.u8vng@burditt.org (Gordon Burditt) - 2011-07-11 18:45 -0500
Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-14 23:07 -0500
Re: Arithmetic overflow checking Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-07-10 12:25 -0400
Re: Arithmetic overflow checking Robert Wessel <robertwessel2@yahoo.com> - 2011-07-10 10:47 -0500
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 07:58 -0700
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-11 10:48 -0700
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 14:40 -0700
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-11 14:54 -0700
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 15:55 -0700
Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-11 21:51 -0400
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 21:31 -0700
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-11 23:16 -0700
Re: Arithmetic overflow checking James Kuyper <jameskuyper@verizon.net> - 2011-07-12 06:28 -0400
Re: Arithmetic overflow checking David Thompson <dave.thompson2@verizon.net> - 2011-07-24 22:13 -0400
Re: Arithmetic overflow checking Lew Pitcher <lpitcher@teksavvy.com> - 2011-07-25 10:24 -0400
Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-12 09:05 +0200
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 02:22 -0700
Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-12 11:34 +0200
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-12 03:04 -0700
Re: Arithmetic overflow checking "Greg A. Woods" <woods@robohack.org> - 2011-07-12 19:55 -0700
Re: Arithmetic overflow checking "Greg A. Woods" <woods@robohack.org> - 2011-07-12 21:54 -0700
Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-14 23:28 -0500
Re: Arithmetic overflow checking "Greg A. Woods" <woods@robohack.org> - 2011-07-19 17:16 -0700
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 03:33 -0700
Re: Arithmetic overflow checking David Lamb <dalamb@cs.queensu.ca> - 2011-07-12 08:29 -0400
Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-12 13:18 +0200
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 11:39 -0700
Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-12 12:38 -0700
Re: Arithmetic overflow checking markspace <-@.> - 2011-07-12 13:20 -0700
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 13:23 -0700
Re: Arithmetic overflow checking Martin Gregorie <martin@address-in-sig.invalid> - 2011-07-12 21:08 +0000
Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-12 14:48 -0700
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 15:24 -0700
Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-12 16:09 -0700
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-13 10:38 -0700
Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-13 11:00 -0700
Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-13 12:16 -0700
Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-13 13:10 -0700
Re: Arithmetic overflow checking markspace <-@.> - 2011-07-13 13:21 -0700
Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-13 13:41 -0700
Re: Arithmetic overflow checking Robert Wessel <robertwessel2@yahoo.com> - 2011-07-14 21:10 -0500
Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-15 11:57 +0200
Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-15 04:36 -0700
Re: Arithmetic overflow checking "Greg A. Woods" <woods@robohack.org> - 2011-07-12 20:03 -0700
Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-13 00:52 -0700
Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-13 07:45 -0700
Re: Arithmetic overflow checking "Greg A. Woods" <woods@robohack.org> - 2011-07-13 11:28 -0700
Re: Arithmetic overflow checking "Greg A. Woods" <woods@robohack.org> - 2011-07-13 11:15 -0700
csiph-web