ALTD + ALTS on the same instruction?

ManAtWork

I'm sure this question has been asked before, but I don't find any clues...

Say, I want to set a field of pins to a field of values. Can I do something like this?

              mov       axis,#0
              rep       @RegLoop,#NumAxes       ' output all pin states
              altd      axis,#freq
              alts      axis,#pinStp0
              wypin     freq,pinStp0
              add       axis,#1
RegLoop

I mean, is the first ALTD smart enough to recognize that I want to modify D of the wypin instruction and not the ALTS instruction? If not, how could I solve this?

Wuerfel_21

nope, can't do it. In that example, ALTD will modify the D slot of ALTS.

The easy fix is to grab the S value separately with ALTS+MOV (+1 insn).

But since you're doing a loop, you can use ALTI instead and it will actually have less instructions in the loop

It'd look something like (untested)

              sets      axis,#freq
              setd      axis,#pinStp0     
              rep       @RegLoop,#NumAxes       ' output all pin states
              alti      axis, #%000_111_111 ' substitute S/D from axis and increment both
              wypin     0-0,0-0
RegLoop

ManAtWork

Ah yes, thank you very much! I knew I have read something about ALTI, lately. But it was somehow to complex to really stay in my memory. Good to have that external memory = forum

Wuerfel_21

I never remember the magic values it needs to work, but https://p2docs.github.io/indir.html#alti has them all written down