alan%cucca@cucca.UUCP (04/28/86)
Is anyone porting GNU Emacs to the IBM RT PC running ACIS 4.2 BSD? I've spent several hours with it but am leaving for a vacation soon and am not much closer than when I started. The major problem I've run into is that the Lisp_Object can't be an int with shifting and masking used to pull out the type and val since val may very well be a full 32-bit int. Specifically, when the val is used as a pointer cast to an unsigned (to point to a struct for example) you get in trouble. All the struct pointer macros use the XUINT macro which sets the Lisp_Object to be an unsigned :24. The RT starts the data space off at 0x10000000, so using 24 bits of it gets you a pointer into the text segment! This leads to using the Lisp_Object union instead of the int with shifts and masks. Now, you've got a 2-word object which is a pain to do things like EQ and NULL on. Sigh. If anyone wants what I've done so far, reply by Tuesday afternoon. I at least got past a couple of the problems with malloc croaking (&etext != start of data segment on this machine by a long shot!). Alan Crosswell Columbia University alan@columbia.edu ...!seismo!columbia!alan
rlk%mit-trill@mit-trill.UUCP (04/29/86)
We are very close to having a port to the RT available. There are a lot of very strange things about the RT -- it wasn't very easy. -- Robert^Z