JackAsser
Registered: Jun 2002
Posts: 2014 |
Quote: yesyes, i understand clearing and EOR take the same time always... I can code too, ya know :D
let's calc..
eor+sta takes 6 cycles per byte (if you plot inside the eor-speedcode, that is). 'dumb' clearing takes 4 cycles/byte (storing 0 in the eor-speedcode).
that's 10 cycles per byte. Let's say half of the screen get's updated, then you have 40*200/2 = 4000 bytes = 40.000 cycles saved. So that's about 2 frames.
Now let's do some maths..
fps frames/update VICX frames/update VICX fps speed increase
1 50,0 48,0 1,0 4%
2 25,0 23,0 2,2 9%
3 16,7 14,7 3,4 14%
4 12,5 10,5 4,8 19%
5 10,0 8,0 6,3 25%
6 8,3 6,3 7,9 32%
7 7,1 5,1 9,7 39%
8 6,3 4,3 11,8 47%
9 5,6 3,6 14,1 56%
10 5,0 3,0 16,7 67%
11 4,5 2,5 19,6 79%
12 4,2 2,2 23,1 92%
13 3,8 1,8 27,1 108%
14 3,6 1,6 31,8 127%
15 3,3 1,3 37,5 150%
16 3,1 1,1 44,4 178%
17 2,9 1,0 50,0 194%
18 2,8 1,0 50,0 178%
19 2,6 1,0 50,0 163%
20 2,5 1,0 50,0 150%
21 2,4 1,0 50,0 138%
22 2,3 1,0 50,0 127%
23 2,2 1,0 50,0 117%
24 2,1 1,0 50,0 108%
25 2,0 1,0 50,0 100%
No idea how many fps it can do now though, but this should give a good idea about the increase in speed.
I'd call anything above 10fps good for c64 purposes.. considering that, it's a bit disappointing that only the 7-9 fps get boosted to 10fps..
The speed up would be greater actually since the C64-version didn't have memory for a fully unrolled filler and clearer. The C128-version have that otoh + relocatable ZP and stack optimizations so I guess with VICX it would be somewhat close to the C128-version except for not using the 2mhz-mode. |
