http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56875
--- Comment #2 from Jan-Benedict Glaw <jbg...@lug-owl.de> ---
This is gas's tc-vax.c:
3158 if ((is_absolute) && (expP->X_op != O_big))
3159 {
3160 /* If nbytes > 4, then we are scrod. We
3161 don't know if the high order bytes
3162 are to be 0xFF or 0x00. BSD4.2 & RMS
3163 say use 0x00. OK --- but this
3164 assembler needs ANOTHER rewrite to
3165 cope properly with this bug. */
3166 md_number_to_chars (p + 1, this_add_number,
3167 min (sizeof (valueT),
3168 (size_t) nbytes));
3169 if ((size_t) nbytes > sizeof (valueT))
3170 memset (p + 1 + sizeof (valueT),
3171 '\0', nbytes - sizeof (valueT));
3172 }
[...]
This is for "small" values (ie. "-1" fitting in a 32bit valueT) and it doesn't
properly sign-extend in this case. Taking into account the next couple lines
(not shown here), this part of the code needs to rethought.
A workaround would be to actually place an all-hex value (through GCC) here,
but that wouldn't fix gas for any hand-written assembler.
