Sent from my iPhone
On Sep 21, 2008, at 9:00 AM, "john dot spelis at 3dlabs dot com" <[EMAIL PROTECTED]
> wrote:
An expression using ptr arithmetic yields an unusual result
unless a cast is applied;
The problematic expression;
MaxTimings = ((EDIDDetailed *) &pExt->checksum) - pDTD;
That is a signed division while the below is unsigned.
works only when cast as;
MaxTimings = (((uintptr_t) &pExt->checksum) - ((uintptr_t)
pDTD))/sizeof(*pDTD);
This occurs on compilers back to 3.0.3 when testing on a x86. It's
also present
in a cross compiler built using 4.3.0 source
Works on a Sun/Solaris compiler.
A test program is attached
--
Summary: Pointer arithmetic yields strange result
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: john dot spelis at 3dlabs dot com
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37609
