Yahtzee

dice = scrap    ;5 bytes, current dice state
round=scrap+5   ;counter for which round we are on

Yahtzee:
    ld a,r          ;\
    ld h,a          ; |
    xor 77          ; |initialize PRNG seeds
    ld l,a          ; |
    ld (seed1),hl   ; |
    ld (seed2),hl   ;/
main:
    ld hl,$8080     ;\
    ld (dice),hl    ; |Reset the dice to the "needs rerolling state"
    ld (dice+2),hl  ; |
    ld (dice+3),hl  ;/
    call roll       ;Roll the dice for the first step
    ld bc,200h      ;number of rerolls is B, C is the current selected die
    ld hl,dice      ;HL points to the current selected die
waitloop:
    ld a,(kbdScanCode) \ or a \ jr z,waitloop
    cp 15 \ jp z,exit
    cp 55 \ call z,mode \ jr z,waitloop
    cp 10 \ jr nc,$+10 \ call selection \ call render_dice \ jr waitloop
    cp 54 \ jr nz,waitloop
    push hl
    call roll
    pop hl
    djnz waitloop
scorecheck:
;;Check if it's a winning combination
;;Also need some quitting condition. I don't know when the game is over.
    jp main
exit:
;;not sure if you want to do something fancy before exiting
    ret
mode:
;;Bring up options and stuff
    push af
    push hl
    push bc

    pop bc
    pop hl
    pop af
    ret
selection:
;;DOWN needs to deselect the current die from being rerolled.
;;LEFT needs to move the selector to the left, wrapping around.
;;RIGHT needs to move the selector to the right, wrapping around.
;;UP selects the current die for rerolling.
;;ENTER toggles whether o not it gets rerolled
    dec a \ jr nz,$+5 \ res 7,(hl)\ ret
    dec a \ jr nz,$+11 \ dec hl \ dec c \ ret p  \ ld c,4 \ ld hl,dice+4 \ ret
    dec a \ jr nz,$+13 \ inc hl \ inc c \ ld a,c \ sub 5 \ ret nz \ ld c,a \ ld hl,dice \ ret
    dec a \ jr nz,$+5 \ set 7,(hl) \ ret
    ld a,(hl) \ xor 80h \ ld (hl),a
    ret
roll:
    push af
    push hl
    push de
    push bc
    ld hl,dice-1
    call rollSub
    call rollSub
    call rollSub
    call rollSub
    call rollSub
    pop bc
    pop de
    pop hl
    pop af
render_dice:
;;render the scene including dice values
;;Things to consider:
;;      B is the number of rerolls left.
;;      C is the current selected die.
;;      Any dice with bit 7 set means it is up for reroll. If A is the die value:
;;          add a,a \ jr nc,$+ \ <<adjust coord>>
;;          rlca
;;          call drawdie
    push af
    push hl
    push de
    push bc

    pop bc
    pop de
    pop hl
    pop af
    ret
rollsub:
    inc hl
    ld a,(hl) \ add a,a
    ret nc
    push hl
    push bc
seed1=$+1
    ld hl,9999
    ld b,h
    ld c,l
    add hl,hl
    add hl,hl
    inc l
    add hl,bc
    ld (seed1),hl
seed2=$+1
    ld hl,987
    add hl,hl
    sbc a,a
    and %00101101
    xor l
    ld l,a
    ld (seed2),hl
    add hl,bc
    ld l,h \ ld h,0
    ld b,h \ ld c,l
    add hl,hl \ add hl,bc \ add hl,hl
    inc h \ ld a,h
    pop bc
    pop hl
    ld (hl),a
    ret