-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 30.07.2014 04:16, Drew DeVault wrote:
> On another note, we also have an ABI that is primarily designed > for assembly users. This means that it assumes the caller is > responsible for managing registers how they please and expects the > caller to load arguments into specific registers that vary > depending on the syscall being made. See the reference > documentation for details: > > http://www.knightos.org/documentation/reference/system.html > > We can work around this problem by writing verbose C shims around > our syscalls, like so: > > inline void fast_copy(SCREEN *screen) __naked { __asm PUSH IY INC > SP INC SP POP IY PUSH IY CALL FASTCOPY ; Expects IY to be pointer > to display memory DEC SP DEC SP POP IY __endasm; screen; /* Squelch > warning */ } This looks weird to me. You seem to be using memory below the stack pointer to hold some data (the backup of iy). Any interrupt occuring during execution of that code could overwrite the data. > > Is there a more appropriate mechanism for doing this? Ideally we > could mention to the __asm directive which registers we plan on > clobbering and SDCC would figure out the ideal way to work this > into the surrounding code. In the long term, when sdcc gets register arguments, such a feature might be added. > Please note that we may not be able to use the new __asm(...) > format, because we need to preprocess it to resolve FASTCOPY. You can always just write the whole functio in asm using sdcc ccalling convention. Philipp -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iEYEARECAAYFAlPh2+oACgkQbtUV+xsoLpoDJACggtyaNyJ4wc2Kf3XWStHJEPCd rpIAni/8ePwQ3kxRgoNHeq+NOscxI99b =MNJB -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Infragistics Professional Build stunning WinForms apps today! Reboot your WinForms applications with our WinForms controls. Build a bridge from your legacy apps to the future. http://pubads.g.doubleclick.net/gampad/clk?id=153845071&iu=/4140/ostg.clktrk _______________________________________________ Sdcc-user mailing list Sdcc-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/sdcc-user
