Dan -- On Fri, 2001-10-26 at 16:38, Dan Sugalski wrote: > Okay, here are the conventions.
Looks like I'm going to have to write some real logic in jakoc pretty soon... > *) The callee is responsible for saving and restoring non-scratch registers Nice for callee since if its work fits into five regs of each type its not going to have to do any saves or restores. Caller, though, is going to have to vacate those regs. So, if caller got args in those regs and then calls anyone else, it has to move them from those regs (or save them). > *) The first five registers (I0-I4, S0-S4, P0-P4, N0-N4) are scratch and do > not have to be preserved by the callee Still thinking about this... We are reducing the overall number of reg copies going on by adding these special cases. I just wish we had an approach that was both uniform (simple, no special cases) and fast too. > *) In *ALL* cases where the stack is used, things are put on the stack in > *reverse* order. The topmost stack element *must* be the integer count of > the number of elements on the stack OK. > *) The callee is responsible for making sure the stack is cleaned off. So, in the case of zero args, do we still push a zero on the stack to make a proper frame? I think yes... > > Inbound args > ============ > If the called subroutine has a fixed number of arguments, they will be > placed in the first five registers of the appropriate register types. First > integer goes in I0, second in I1, and so on. > > If there are too many arguments of a particular type the overflow go on the > stack. If there are a variable number of arguments, all the *non* fixed > args go on the stack. So for right now, just pretend that all Jako subroutines take a variable number of args.. :) (Until I get the time to write fully compatible conventions in jakoc, anyway). Can we have ops to inquire on the type of the topmost stack entry? [snip] Regards, -- Gregor _____________________________________________________________________ / perl -e 'srand(-2091643526); print chr rand 90 for (0..4)' \ Gregor N. Purdy [EMAIL PROTECTED] Focus Research, Inc. http://www.focusresearch.com/ 8080 Beckett Center Drive #203 513-860-3570 vox West Chester, OH 45069 513-860-3579 fax \_____________________________________________________________________/
