So, do you want the good news or the - no wait, good news is all#

Sat, 16 Mar 2002 04:07:34 +0000

So, do you want the good news or the - no wait, good news is all there is right now. Good news or no news, I guess. Sorry.

SBCL PPC forward port progressed, uh, forwards. Most of it was renaming, and most of the renaming had already been done (thanks, Christophe). The only part requiring actual thought was that it wouldn't compile branches to targets more than 32k away. Disturbingly, this looks like a problem shared by CMUCL in its PPC and MIPS backends, unless they've done something magic I don't understand. Mail to cmucl-imp called for, tomorrow. Granted, it's not a bug that shows often, I expect - it's rare that a single function has a branch target more than 32k distant. Anyway, there's now additional magic in emit-conditional-branch: instead of emit-back-patch (which emits variable numbers but a fixed length of instructions) it has to emit-chooser. This lets us have different forms for when the branch is short and when it exceeds 32k, in which case we code a one-instruction jump with an inversion of the test condition, then an unconditional branch to the proper target: we turn

beq .far_away
stuff
.far_away

into

bne .skip
b .far_away
.skip
stuff
.far_away

and ditto for other conditions. I just looked in on the progress of the native compilation and it had got all the way to second genesis. Admittedly at that point it had crashed with a segmentation fault, but it looks like it had simply run out of memory. 64Mb is not enough for anyone. So, edited some numbers and I need to crosscompile again in the morning.

All being well, this means I have to start trying to remember what state I left my MP efforts in. Or time out and play with asdf for a while longer, but I seem to be on an SBCL roll right now and might as well get on with it.

Non-geek activities: ahh, that'd be the no news, I guess