I am in favor of adding a cli option to enable the old calling method. This change can break nearly every naked member we have if I understand correctly, and without clear notice we may be compiling code for the old convention, which will just cause huge headaches.
Which convention used is not important to me, but I wonder what the cause for the change is. Is it faster somehow? On Fri, Jul 30, 2021, 3:35 PM Philipp Klaus Krause <p...@spth.de> wrote: > Am 30.07.21 um 15:12 schrieb a...@etchedpixels.co.uk: > > On Tue, 27 Jul 2021 23:15:32 +0200 > > Philipp Klaus Krause <p...@spth.de> wrote: > > > >> A new calling convention for z80ยน has been implemented in the > >> breaktheworld branch: > >> https://sourceforge.net/p/sdcc/code/HEAD/tree/branches/breaktheworld/ > >> > >> Anyone wanting to test it or experiment with it is welcome to use the > >> branch. > > I don't think there will be big changes to what is implemented in the > branch, but I can't fully rule them out either - especially wrt. stack > cleanup for funtions returning float. Also, if many SDCC users dislike > the proposed changes, there is still the possibility of not changing the > convention at all. > > > It would be useful if you described the change as it's a bit hard to > > assess a new ABI without explanation. > > There is documentation in the manual in that branch, but here are the > changes (for z80, z180, z80n - other ports are likely to use something > else): > > * Return values: > - Old: l for 8 bit, hl for 16 bit, dehl for 32 bit > - New: a for 8 bit, de for 16 bit, hlde for 32 bit > * Parameters: > - Old: Always all on stack > - New: All on stack for functions with variable arguments, otherwise: > - First parameter in a if 8 bit, hl if 16 bit, hlde if 32 bit. > - If first parameter is in a, and second has 8 bits, it is in l > - If first parameter is in a or hl, and the second has 16 bits, > it is in de > - Other parameters on the stack > * Stack cleanup: > - Always done by caller > - New: Done by caller with the following exceptions: > - Functions that return at most 16 bits (e.g. void, char, int) and > do not have variable arguments > - Functions that return float and > have a first parameter of type float and > do not have variable arguments > > > Also can we please have defines > > from the compiler for ABI breakage so that code can do > > > > #if (__SDCC_Z80_ABI == 2) > > #define asmcall xxx > > #else > > #define asmcall yyy > > #endif > > The original plan was to just use the version number. But since it now > has become clear that some users would not want the change, if we still > change the default, we'd need such a define to go along with a > --stdccoldcall command-line option to restore the old default behaviour. > > Philipp > > > _______________________________________________ > Sdcc-user mailing list > Sdcc-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/sdcc-user >
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