I am getting a floating point alignment exception during a GHC 6.4.2 bootstrap on hpux 11.0 -- the stage 1 ghc core dumps. The stack trace looks like this: (gdb) where #0 0x1ac0df8 in __gmpn_mul_1 () #1 0x1abdd24 in __gmpz_mul () #2 0x1aa2ef4 in timesIntegerzh_fast () #3 0x1ab8124 in StgRun () #4 0x1a9bc08 in schedule () #5 0x1a9c5f4 in waitThread_ () #6 0x1a9c52c in scheduleWaitThread () #7 0x1a99a88 in rts_evalLazyIO () #8 0x1a990dc in main () (gdb) The timesIntegerzh_fast routine is calling into libgmp, libgmp is then core dumping because of an access to a double with bad alignment -- it is trying to load a double from a 4-byte aligned address -- hpux requires 8 byte alignment. The code for timesIntegerzh_fast comes from PrimOps.cmm. It is making use of these memory locations: section "bss" { mp_tmp1: bits8 [SIZEOF_MP_INT]; } section "bss" { mp_tmp2: bits8 [SIZEOF_MP_INT]; } section "bss" { result1: bits8 [SIZEOF_MP_INT]; } section "bss" { result2: bits8 [SIZEOF_MP_INT]; } Might this alignment problem be fixed by adding in some "align 8" statements? Joe Buehler