Monthly Archives: August 2009

Learning IA-64 assembly

While testing EGLIBC 2.10.1 on all Debian architectures, I have discovered that the testsuite on IA-64 fails for the new POSIX 2008 math tests. I have reported the problem both upstream and on debian-ia64@lists.debian.org, but without success.

IA-64 being one of the last architecture (with HPPA) on which EGLIBC 2.10.1 fails to build from sources, I have decided to spend my day fixing the problem and digging into the corresponding IA-64 assembly code. The mathematical functions on this architecture are based on the Highly Optimized Mathematical Functions for the Intel® Itanium™ Architecture. Using the Intel® Itanium™ Architecture Software Developer’s Manual and after a lot of tries, I have been able to add the missing code paths needed for POSIX 2008 compliance, and also fixed a few bugs on the stack frame allocation (arguments of the alloc instruction).

The resulting patch is now in the pkg-glibc SVN and in the upstream bugzilla.

And more important, I have learned the basic about IA-64 assembly!