From: Piotr Fusik (P.Fusik_at_elka.pw.edu.pl)
Date: 2003-01-13 18:44:05
Hi, My "philosophy" is that if I don't know how something works, I keep it unchanged, not clear it. :) In 65CE02 bit 5 enables 8-bit stack pointer (default compatibility mode). If you clear it, you enable 16-bit stack pointer. So why not change: lda (ptr1),y and #%11001111 to: php pla eor (ptr1),y and #%00110000 eor (ptr1),y ? That's only 4 bytes and 12 cycles more. Piotr On Thu, 9 Jan 2003, Ullrich von Bassewitz wrote: > On Thu, Jan 09, 2003 at 03:20:42PM +0100, Piotr Fusik wrote: > > > Ok, but why do you think that clearing (and not setting) them is always > > good? > > This is getting more and more a philosophical discussion, since these values > are ignored by a 6502 CPU anyway:-) I'm resetting anything that I don't want > to be set. I think this is good practice, even if it may be superflous in the > given case. Why do you think that the AND is evil in this place? > > > Maybe we should dig in some 65xx docs to know possible uses of these bits? > > They are only used on CPUs not supported by cc65, so we don't need to care > about that, I think. > > Regards > > > Uz > > > -- > Ullrich von Bassewitz uz_at_musoftware.de > ---------------------------------------------------------------------- > To unsubscribe from the list send mail to majordomo_at_musoftware.de with > the string "unsubscribe cc65" in the body(!) of the mail. > ---------------------------------------------------------------------- To unsubscribe from the list send mail to majordomo_at_musoftware.de with the string "unsubscribe cc65" in the body(!) of the mail.
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