Re: A82: Random routine

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Re: A82: Random routine


I looked at the previous scheme of shuffling a deck for O(n) performance.
This is what i came up with.  It's going to be a much more random stack by
getting a random number out of a seed rather than using "ld a,r"


same_code:

shuffle:
 ld hl,cards            ; start of 20 byte array
 ld b,20
shuffle_loop:
 push bc
 call getrand
 ld de,cards
 or %1111               ; between 0 and 15
 ld b,a
 srl a
 srl a
 add a,b                ; between 0 and 18
 add a,e
 ld e,a
 ld b,(de)
 ldi                    ; (de) = (hl) /*/  hl++ /*/ de++
 ld (hl),b
 pop bc
 djnz shuffle_loop

getrand:                ; by Jason Todd
 ld a,(randseed)
 ld b,a
 ld a,r
 add a,b
 sla b
 sla b
 add a,b
 sla b
 sla b
 add a,b
 add a,e
 inc a
 rrc a
 ld (randseed),a
 ret

randseed: .db %10101010    ; im guessing this is better to start it off
weird than at zero
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