A82: fast multiply...

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A82: fast multiply...

Hello!
As the Z80 doesn't have a multiply instruction (which is almost
necessary for star-scrolls and things like that) then I've tried to do
my own routines. It surely works, but I think it takes more than 80
cycles to execute. (here's the code:)

Multiply:
; Multiplies b and de and gives the product in hl
    ld  hl,0
    ld  a,1
mulloop:
    ld  c,a
    and b
    jr  z,noadd
    add hl,de
noadd:
    ld  a,c
    sla e
    rl  d
    add a,a
    jr  nc,mulloop
    ret

Someone must have written a faster way of mulitplying two 8-bit numbers
than this, or...? If so, could you reply to this and show your routines?

(by the way: is there a fast way for integer division, too?)

Lars Ahlzen
lars.ahlzen@swipnet.se
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