[Coco] Mod10 Suggestions
msmcdoug at iinet.net.au
Thu Feb 16 21:19:21 EST 2017
On 17/02/2017 12:26 PM, William Mikrut wrote:
> Following is a MOD10 program I have used for years in IBM programs.
> I have translated it the best I can...I am sure it is not the most
> efficient... and I have much to learn.
I can't go through it now but a couple of things jump out at me
* Rather than using LDB A,X to get the next digit, simply increment X
each time through the loop, using auto-increment.
* Multiply by 2 is a left shift. Because your digits are 0-9, you'll
never get overflow.
* Why sub 10, then add 1? Why not sub 9?
* I'd probably store the loop counter on the direct page myself.
* Count from 15 to 0 (-1) to eliminate CMPA #0 (which can be replaced
with TSTA in this case)
* Should be STB RESULT (no hash)
I'm sure Simon can get this down to 4 lines (with music)! ;)
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