; NumberJack: a number-only blackjack game in MU8A for the mu808 VM
;
; How to play:
; * you start with a $1000 balance
; * on each round, enter your bet
;   (the game will quit if the bet is above your balance)
; * the first card of the dealer's hand will be shown
;   (hands are shown with a leading 1 that you must ignore)
;   (card values are: 1 is ace, 2 to 9 are "as is", 0 is 10 to K)
; * on the first turn, select 0 (stand), 1 (hit) or 2 (double)
; * on each next turn, select 0 (stand) or 1 (hit)
; * as a result of the round, the dealer's final hand will be shown
;   first and then yours
; * the dealer must draw on 16 and stand on any 17
; * player's blackjack pays 3 to 2
;
; Created by Luxferre in 2025, released into public domain

; constants section
set 10 0 51   ; set constant 10 to loc 51
set 100 0 52  ; set constant 100 to loc 52
set 13 0 53   ; upper RNG limit to loc 53
set 16 0 54   ; dealer draw limit to loc 54
set 21 0 55   ; 21 score limit to loc 55 
set 12 0 56   ; 12 score limit to loc 56
set 1000 0 60 ; set $1000 initial balance
set 2 0 57    ; set constant 2 to loc 57
set 36 0 58   ; set constant 36 to loc 58
set 101 0 80  ; set the first blackjack condition to loc 80
set 110 0 81  ; set the second blackjack condition to loc 81
juc :main     ; jump to the main code

; subroutines section (return address is in loc 99)
; random card pulling procedure (result is in loc 2, from 0 to 9)
:gcard rnd 127 53 1 ; set loc 1 to random integer between 1 and 13
div 1 51 2          ; divide it by 10 into loc 2
mdf 2 0 2           ; get the floor part of the result into the same loc 2
sub 127 2 2         ; subtract it from 1
mul 1 2             ; multiply by the random choice itself, result is in loc 2
iuc 99              ; jump to the return address in loc 99

; score evaluation procedure
; param is in loc 1, resulting scores are in locs 2 and 3
:score set 0 0 2 ; set score1 to 0
set 0 0 8        ; set aces to 0
:slp mdf 1 51 4  ; get the current digit n of val
div 1 51 1       ; divide val by 10
mdf 1 0 1        ; get the floor part into the same loc
jgt 4 :scn       ; skip if n > 0
fma 51 127 4     ; add 10 to n
:scn fma 4 127 2 ; add n to score1 at loc 2
sub 4 127 5      ; subtract 1 from n to loc 5
jne 5 :sc2       ; skip if n != 1
inc 8            ; increment aces count at loc 8
:sc2 sub 1 127 5 ; subtract 1 from val to loc 5
jgt 5 :slp       ; go to loop start if val > 1
dva 2 3          ; assign score2 (at loc 3) = score1 (at loc 2)
sub 8 127 5      ; subtract 1 from aces (loc 8)
jne 5 :send      ; go to procedure end if aces != 1
sub 2 56 5       ; subtract 12 from the score1 value
jge 5 :send      ; go to procedure end if score1 >= 12
fma 51 127 3     ; add 10 to score2 if there was exactly one non-busting ace
:send iuc 99     ; jump to the return address in loc 99

; main code section
; variables:
; 60 - balance, 61 - bet, 62 - dealer's hand, 63 - player's hand, 64 - round
:main out 58 58 1   ; output the dollar sign (if supported)
out 60 60 0         ; output the current balance
jeq 60 :end         ; game over if it's zero
inp 61 61 0         ; input your bet
sub 60 61 60        ; subtract the bet from the balance
jlt 60 :end         ; game over if over balance
dca :r1 99          ; set the return address
juc :gcard          ; call the card generation procedure
:r1 fma 52 51 2     ; loc 2 <- 100 + 10 * card in loc 2
dva 2 62            ; copy the result into loc 62
dca :r2 99          ; set the return address
juc :gcard          ; call the card generation procedure again (in loc 2)
:r2 fma 2 127 62    ; add this result into loc 62 (dealer's hand)
dva 62 1            ; copy the dealer's hand as the proc parameter 
dca :r3 99          ; set the return address
juc :score          ; call the scoring procedure
:r3 sub 3 55 5      ; we only have to compare score 2 to 21
jeq 5 :main         ; start the loop over if we have dealer's blackjack
dca :r4 99          ; set the return address
juc :gcard          ; call the card generation procedure
:r4 fma 52 51 2     ; loc 2 <- 100 + 10 * card in loc 2
dva 2 63            ; copy the result into loc 63 (player's hand)
dca :r5 99          ; set the return address
juc :gcard          ; call the card generation procedure again (in loc 2)
:r5 fma 2 127 63    ; add this result into loc 63 (player's hand)
div 62 51 5         ; get the start of the dealer's hand by dividing it by 10...
mdf 5 0 5           ; and getting the floor part
out 5 5 0           ; display the start of the dealer's hand
set 0 0 64          ; set the round index to 0
set 0 0 9           ; set the stand flag to 0
:rnl out 63 63 0    ; start of the inner player loop, display the player's hand
inp 6 6 0           ; input the action into loc 6
jeq 6 :std          ; jump to stand action if 0
sub 6 127 5         ; check if 1
jeq 5 :hit          ; jump to hit action if 1
sub 5 127 5         ; check if 2
jeq 5 :dbl          ; jump to double action if 2
juc :skp            ; jump to skip otherwise
:dbl jne 64 :skp    ; skip double if not the first round
sub 60 61 60        ; subtract more balance
mul 57 61           ; double the bet
set 1 0 9           ; set the stand flag, proceed to the hit section next
:hit dca :r6 99     ; set the return address
juc :gcard          ; call the card generation procedure
:r6 fma 2 51 63     ; loc 63 <- loc 63 * 10 + card in loc 2
inc 64              ; increment the round index
juc :skp            ; jump to skip afterwards
:std set 1 0 9      ; set the stand flag
inc 64              ; increment the round index
:skp dva 63 1       ; copy the current player's hand to loc 1 as a parameter
dca :r7 99          ; set the return address
juc :score          ; call the scoring procedure
:r7 sub 2 55 5      ; we only have to compare score 1 to 21
jle 5 :nob          ; reloop to beginning if the player is bust
out 63 63 0         ; output the player's hand
juc :main           ; reloop
:nob jeq 9 :rnl     ; repeat the inner player loop if the stand flag is 0
dva 3 72            ; copy the player score 2 to loc 72
set 0 0 9           ; set the stand flag to 0
:rnd dva 62 1       ; start the inner dealer's loop, set the scoring procedure param
dca :r9 99          ; set the return address
juc :score          ; call the scoring procedure
:r9 sub 2 55 5      ; we need to compare score 1 to 21 => loc 5
sub 3 54 6          ; we need to compare score 2 to 16 => loc 6
jgt 5 :s3           ; go to stand if score1 > 21
jgt 6 :s3           ; go to stand if score2 > 16
juc :s4             ; skip if neither
:s3 juc :s5         ; jump outside to stand
:s4 dca :r8 99      ; set the return address
juc :gcard          ; call the card generation procedure
:r8 fma 2 51 62     ; loc 62 <- loc 62 * 10 + card in loc 2
jeq 9 :rnd          ; repeat the inner dealer loop if the stand flag is 0
:s5 out 62 63 0     ; output both hands (dealer's first)
sub 63 80 1         ; compare player hand with 101
jeq 1 :bjk          ; jump to the blackjack condition if equal
sub 63 81 1         ; compare player hand with 110
jeq 1 :bjk          ; jump to the blackjack condition if equal
sub 3 72 1          ; compare dealer score 2 and player score 2
jeq 1 :push         ; push condition
jlt 1 :win          ; player win condition
sub 2 55 1          ; compare dealer score 1 with 21
jgt 1 :win          ; player win condition
juc :main           ; reloop to beginning
:bjk div 61 57 1    ; halve the bet
fma 1 127 60        ; add half the bet (for blackjack calc)
:win fma 61 127 60  ; add bet first time
:push fma 61 127 60 ; add bet second time
juc :main           ; reloop to beginning
:end nnn            ; just a nop label for the program end