brooke/mandel-6502
1
0
Fork 1
Code Issues Pull requests Projects Releases Packages Wiki Activity

apply jamey's suggestion of skipping add for high byte muls

Browse source 
rather than saving 0 into the high bytes, then adding the high-byte
multiplication later, write it directly in place. this saves a few
cycles on every iteration, and it adds up nicely.

View 1 overview render times:
130XE: 10.050 ms/px - 4m56s
800XL: 10.906 ms/px - 5m21s
This commit is contained in:
Brooke Vibber 2025-01-04 10:53:51 -08:00
commit 582ddf497f
2 changed files with 4 additions and 28 deletions
Download patch file Download diff file Expand all files Collapse all files

3
todo.md
View file

@ -1,8 +1,5 @@
things to try:
* skip add on the top-byte multiply in sqr8/mul8
* should save a few cycles, suggestion by jamey
* patch the entire expanded-ram imul8xe on top of imul8 to avoid the 3-cycle thunk penalty :D
* y-axis mirror optimization