I do have a 24-bit floating-point multiplication routine

saved 2 bytes, 1149 cycles saved by using iy too (and in a way compatible with TIOS, imagine that)

Code: [Select]

; hldebc = hlc * bde
ld (iy+asm_Flag1),b
xor a
ld ix,0
ld b,24
Loop:
add ix,ix
rla
rl c
adc hl,hl
jr nc,Next
add ix,de
adc a,(iy+asm_Flag1)
rl c
jr nc,Next
inc hl
Next:
djnz Loop
ld e,a
ld d,c
push ix ; ld c,ixl
pop bc ; ld b,ixh


Jacobly, are you sure this works because I've been going through the code and it seems to me like the second 'rl c' should instead be 'add carry flag to c'. 2 times 'rl c' per loop seems wrong to me. Could you explain please? Because I've tried it as well in wabbitemu, taking the different input in account, and it is still not doing the right thing.

I wouldn't know where to start, I'm having problems enough with 24bit multiplication...

Ok, this is a bit of a stretch, but how about square-rooting a 24-bit number

Interesting question. I have thought about this myself since I would need to square as well for the Mandelbrot formula. I would just multiplicate normally, but I bet there could be some optimization when both the multiplier and multiplicator are the same. Perhaps you could try something with just 8 bits first to keep it simple and then if it works, work up to 24 bits.

EDIT: Sorry, read you question wrong.. thought you meant squaring. Square-rooting would be a little harder I suppose...

Thanks a lot jacobly for your reply!

So, those 2 routines, are they for floating point numbers or for integers? I assume the latter, but just to be sure
Any idea how long they take to complete on average? I could count myself but seeing you talking about saving 1149 cycles makes me think you have an idea yourself

Ah, I was right, you are the one! Thanks a lot for sending it to ticalc.org. It was really exciting to see it on top of the front page!

Wow, this looks really excellent. The graphics and effect really make this game stand out. Fantistic work! =)

Thanks! I think most game programmers out there don't put enough attention to the graphics. For me, those are always pretty important. They add so much to the feel of a game IMO.

Nice. I saw it on ticalc for a while but was not sure if it was the final version. You should really e-mail them because this deserves a front page mention there.

And how would I go about that? I mean I can't just tell them that they should can I?

Sorry for the belated reply by the way. I turned the notify on but apparently they ended up in the junk part of my inbox...