( utility macros )

%INC-X { .Screen/x DEI2 #0008 ADD2 .Screen/x DEO2 } ( -- )
%INC-Y { .Screen/y DEI2 #0008 ADD2 .Screen/y DEO2 } ( -- )

%CENTER-X { .Screen/width DEI2 #01 SFT2 }
%CENTER-Y { .Screen/height DEI2 #01 SFT2 }

%MOD { DIVk MUL SUB }
%MOD2 { DIV2k MUL2 SUB2 }

%2**  { #10 SFT2 } %2// { #01 SFT2 }
%8**  { #30 SFT2 } %8// { #03 SFT2 }
%TOS  { #00 SWP }  %TOB { SWP POP }

%NEXT-TILE { DUP2 #0010 ADD2 }
%GET-USABLE-HEIGHT { .Screen/height DEI2 #0050 SUB2 #03 SFT2 SWP POP }

%RTN { JMP2r }

( devices )

|00 @System     [ &vector $2 &wst      $1 &rst    $1 &pad   $4 &r      $2 &g      $2 &b    $2 &debug  $1 &halt $1 ]
|10 @Console    [ &vector $2 &read     $1 &pad    $5 &write $1 &error  $1 ]
|20 @Screen     [ &vector $2 &width    $2 &height $2 &auto $1 &pad   $1 &x      $2 &y      $2 &addr $2 &pixel  $1 &sprite $1 ]
|30 @Audio0     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|40 @Audio1     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|50 @Audio2     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|60 @Audio3     [ &vector $2 &position $2 &output $1 &pad   $3 &adsr   $2 &length $2 &addr $2 &volume $1 &pitch $1 ]
|80 @Controller [ &vector $2 &button   $1 &key    $1 ]
|90 @Mouse      [ &vector $2 &x        $2 &y      $2 &state $1 &wheel  $1 ]
|a0 @File       [ &vector $2 &success  $2 &offset-hs $2 &offset-ls $2 &name   $2 &length $2 &load $2 &save   $2 ]
|b0 @DateTime   [ &year   $2 &month    $1 &day    $1 &hour  $1 &minute $1 &second $1 &dotw $1 &doty   $2 &isdst $1 ]

( variables )

|0000

@state $1
@ticker $1
@anim-speed $1

@logo-coords [
  &x $2
  &y $2
]

@list-len $2
@list-offset $1
@list-elem-offset $1
@list-top $1
@list-height $1
@select-index $1
@ncarts $1
@btn-state $1
@sb-len $1
@sb-pos $1
@sb-step $1

@cart-len $1

( program )

|0100 
@init ( -> )

  ( steppewnolf-dark theme ) 
  #02c1 .System/r DEO2 
  #02cd .System/g DEO2 
  #02cb .System/b DEO2

  ( initialize state )
  #00 .ticker STZ
  #00 .state STZ
  #00 .select-index STZ
  #20 .anim-speed STZ
  #ff .btn-state STZ
  GET-USABLE-HEIGHT .list-height STZ
  
  ;carts-file .File/name DEO2
  #2000 .File/length DEO2
  ;list-buf .File/load DEO2
  .File/success DEI2 .list-len STZ2
  
  CENTER-X .logo-coords/x STZ2
  CENTER-Y .logo-coords/y STZ2
  
  ;on-frame .Screen/vector DEO2
  
BRK

@on-frame ( -> )

  .ticker LDZ #01 ADD
  DUP .anim-speed LDZ EQU ,&next-render JCN
  .ticker STZ
  BRK
  
  &next-render
  POP #00 .ticker STZ
  .state LDZ
  
  ( draw uxn logo )
  DUP #00 NEQ ,&state1 JCN
    ;draw-uxn-logo JSR2
    INC .state STZ
  BRK
  
  ( draw first syllable of xrxs logo )
  &state1 DUP #01 NEQ ,&state2 JCN
    ;draw-xrxs-logo-xr JSR2
    INC .state STZ
  BRK
  
  ( draw second syllable of xrxs logo )
  &state2 DUP #02 NEQ ,&state3 JCN
    ;draw-xrxs-logo-xs JSR2
    
    INC .state STZ
  BRK
  
  ( clear screen )
  &state3
    ;clear-screen JSR2
  
  ( move shove logo into top-left corner )
    DUP #03 NEQ ,&state4 JCN
    #04 .anim-speed STZ
    ;scoot-logos JSR2
    ;draw-uxn-logo JSR2
    ;draw-xrxs-logo-xr JSR2
    ;draw-xrxs-logo-xs JSR2
    .logo-coords/x LDZ2 #0020 GTH2 ,&keep-state JCN

      INC .state STZ 
      ;get-select-idx-by-mouse .Mouse/vector DEO2
      ;get-select-idx-by-key .Controller/vector DEO2 BRK
    &keep-state POP
  BRK
  
  ( render the cartridge list interface )
  &state4 DUP #04 NEQ ,&state5 JCN
    ;draw-gray-borders JSR2
    ;draw-bl-scanlines JSR2
    ;draw-tl-scanlines JSR2
    ;draw-tr-scanlines JSR2
    ;draw-br-scanlines JSR2
    ;draw-uxn-logo JSR2
    ;draw-xrxs-logo-xr JSR2
    ;draw-xrxs-logo-xs JSR2
    [ ;title-loadCart
      CENTER-X OVR2 ;strlen JSR2 #20 SFT2 SUB2
      #0010
      #02 ] ;draw-string JSR2
    ;render-cart-list JSR2
    ;draw-scrollbar JSR2
    ;draw-pointer JSR2
    POP
  BRK

  ( confirm the selected cartridge )
  &state5 DUP #05 NEQ ,&state6 JCN
    ;draw-gray-borders JSR2
        ;draw-bl-scanlines JSR2
        ;draw-tl-scanlines JSR2
        ;draw-tr-scanlines JSR2
        ;draw-br-scanlines JSR2
        ;draw-uxn-logo JSR2
        ;draw-xrxs-logo-xr JSR2
        ;draw-xrxs-logo-xs JSR2
        [ ;title-confirmCart
          CENTER-X OVR2 ;strlen JSR2 #20 SFT2 SUB2
          #0010
          #02 ] ;draw-string JSR2
        ;render-cart-list JSR2
        ;draw-scrollbar JSR2
        ;draw-confirm-buttons JSR2
        ;draw-pointer JSR2
        POP
      BRK
  &state6
    [ ;load-cmd
      CENTER-X OVR2 ;strlen JSR2 #20 SFT2 SUB2 
      CENTER-Y #0004 SUB
      #02 ] ;draw-string JSR2
    POP
BRK

@clear-screen ( -> )
 
  .Screen/width DEI2 #0000 &whilex EQU2k ,&endx JCN
    DUP2 ,&x STR2
    .Screen/height DEI2 #0000 &whiley EQU2k ,&endy JCN
      DUP2 ,&y STR2
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      ;blank .Screen/addr DEO2
      #10 .Screen/sprite DEO
      #40 .Screen/sprite DEO
    #0008 ADD2 ,&whiley JMP &endy POP2 POP2
  #0008 ADD2 ,&whilex JMP &endx POP2 POP2
  
RTN
&x $2
&y $2

@scoot-logos ( -> )

  .logo-coords/x LDZ2 #0021 LTH2 ,&no-scoot-x JCN
    .logo-coords/x LDZ2 #01 SFT2
    .logo-coords/x STZ2
  &no-scoot-x
  
  .logo-coords/y LDZ2 #0021 LTH2 ,&no-scoot-y JCN
    .logo-coords/y LDZ2 #01 SFT2
    .logo-coords/y STZ2
  &no-scoot-y

RTN

@draw-uxn-logo ( -> )

  .logo-coords/x LDZ2 #0020 SUB2 .Screen/x DEO2
  .logo-coords/y LDZ2 #0010 SUB2 .Screen/y DEO2
  
  #0100 #0000 &while EQU2k ,&end JCN
    DUP2 ;uxn-logo ADD2 .Screen/addr DEO2
    #c1 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0030 AND2 #0000 NEQ2 ,&no-inc-y JCN
      .logo-coords/x LDZ2 #0020 SUB2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while JMP &end POP2 POP2
  
RTN

@draw-xrxs-logo-xr ( -> )

  .logo-coords/x LDZ2 .Screen/x DEO2
  .logo-coords/y LDZ2 #0010 SUB2 .Screen/y DEO2
  
  #0080 #0000 &while EQU2k ,&end JCN
    DUP2 ;xrxs-logo ADD2 .Screen/addr DEO2
    #c1 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0030 AND2 #0000 NEQ2 ,&no-inc-y JCN
      .logo-coords/x LDZ2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while JMP &end POP2 POP2
  
RTN

@draw-xrxs-logo-xs ( -> )

  .logo-coords/x LDZ2 .Screen/x DEO2
  .logo-coords/y LDZ2 .Screen/y DEO2
  
  #0100 #0080 &while EQU2k ,&end JCN
    DUP2 ;xrxs-logo ADD2 .Screen/addr DEO2
    #c1 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0030 AND2 #0000 NEQ2 ,&no-inc-y JCN
      .logo-coords/x LDZ2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while JMP &end POP2 POP2
  
RTN

@draw-gray-borders ( -> )

  ;blank .Screen/addr DEO2
  #0028 #0000 &whilemtop EQU2k ,&endmtop JCN
    DUP2 .Screen/y DEO2
    .Screen/width DEI2 #0000 &whiletop EQU2k ,&endtop JCN
      DUP2 .Screen/x DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whiletop JMP &endtop POP2 POP2
  #0008 ADD2 ,&whilemtop JMP &endmtop POP2 POP2
  
  #0040 #0000 &whilemleft EQU2k ,&endmleft JCN
    DUP2 .Screen/x DEO2
    .Screen/height DEI2 #0028 SUB2 #0028 &whileleft EQU2k ,&endleft JCN
      DUP2 .Screen/y DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whileleft JMP &endleft POP2 POP2
  #0008 ADD2 ,&whilemleft JMP &endmleft POP2 POP2
  
  .Screen/width DEI2 DUP2 #0040 SUB2 &whilemright EQU2k ,&endmright JCN
    DUP2 .Screen/x DEO2
    .Screen/height DEI2 #0028 SUB2 #0028 &whileright EQU2k ,&endright JCN
      DUP2 .Screen/y DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whileright JMP &endright POP2 POP2
  #0008 ADD2 ,&whilemright JMP &endmright POP2 POP2
  
  .Screen/height DEI2 DUP2 #0028 SUB2 &whilembottom EQU2k ,&endmbottom JCN
    DUP2 .Screen/y DEO2
    .Screen/width DEI2 #0000 &whilebottom EQU2k ,&endbottom JCN
      DUP2 .Screen/x DEO2
      #84 .Screen/sprite DEO
    #0008 ADD2 ,&whilebottom JMP &endbottom POP2 POP2
  #0008 ADD2 ,&whilembottom JMP &endmbottom POP2 POP2
  
RTN
    

( come up with a more elegant way to draw these )

@draw-bl-scanlines ( -> )
  CENTER-Y ,&y STR2
  #0008 ,&x STR2
  
  &whileld
  ,&y LDR2 CENTER-Y SUB2 #04 SFT2 DUP2 ADD2 #0008 ADD2 ,&x STR2
  .Screen/height DEI2 #0028 SUB2 ,&y LDR2  LTH2 ,&endld JCN 
    &dlscan #0040 ,&x LDR2 EQU2 ,&enddlscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&dlscan JMP &enddlscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whileld JMP &endld

RTN
&x $2
&y $2

@draw-tl-scanlines
  #0028 ,&y STR2
  #0008 ,&x STR2
  
  &whilelu
  CENTER-Y ,&y LDR2 SUB2 #04 SFT2 DUP2 ADD2 #0008 ADD2 ,&x STR2
  CENTER-Y ,&y LDR2  LTH2 ,&endlu JCN 
    &ulscan #0040 ,&x LDR2 EQU2 ,&endulscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&ulscan JMP &endulscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whilelu JMP &endlu

RTN
&x $2
&y $2
  
@draw-br-scanlines ( -> )
  CENTER-Y ,&y STR2
  .Screen/width DEI2 #0008 SUB2 ,&x STR2
  
  &whilerd
  .Screen/width DEI2 #0040 SUB2 ,&x STR2
  .Screen/height DEI2 #0028 SUB2 ,&y LDR2  LTH2 ,&endrd JCN 
    &drscan .Screen/width DEI2 #0008 SUB2 ,&y LDR2 CENTER-Y SUB2 #04 SFT2 DUP2 ADD2 SUB2 ,&x LDR2 EQU2 ,&enddrscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&drscan JMP &enddrscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whilerd JMP &endrd
RTN
&x $2
&y $2

@draw-tr-scanlines
  #0028 ,&y STR2
  .Screen/width DEI2 #0008 SUB2 ,&x STR2
  
  &whileru
  .Screen/width DEI2 #0040 SUB2 ,&x STR2
  CENTER-Y ,&y LDR2 LTH2 ,&endru JCN 
    &urscan .Screen/width DEI2 #0008 SUB2 CENTER-Y ,&y LDR2  SUB2 #04 SFT2 DUP2 ADD2 SUB2 ,&x LDR2 EQU2 ,&endurscan JCN
      ,&x LDR2 .Screen/x DEO2
      ,&y LDR2 .Screen/y DEO2
      #03 .Screen/pixel DEO
    ,&x LDR2 #0001 ADD2 ,&x STR2 ,&urscan JMP &endurscan
  ,&y LDR2 #0004 ADD2 ,&y STR2 ,&whileru JMP &endru

RTN
&x $2
&y $2


@draw-pointer ( -> )

  ;cursor .Screen/addr DEO2

  .Mouse/x DEI2 .Screen/x DEO2
  .Mouse/y DEI2 .Screen/y DEO2

  #4a .Screen/sprite DEO
  
RTN  

@draw-string ( addr x y color -- )
	
	STH ( save color )
	.Screen/y DEO2 ( set y )
	.Screen/x DEO2 ( set x )

  ( now the string address is at the top of the stack )
  &loop
    LDAk DUP #00 NEQ #20 MUL SUB TOS 8** ;font ADD2 .Screen/addr DEO2 
    STHkr .Screen/sprite DEO
    INC-X
    INC2
    LDAk #00 NEQ ,&loop JCN
  POP2
  POPr

RTN

@strlen ( addr -- len )

  DUP2
  &loop
    INC2 LDAk ,&loop JCN
  SWP2 SUB2
  
RTN

@store-char ( char -- char )

  #00 .list-elem-offset LDZ ;word ADD2 STA
  .list-elem-offset LDZ INC .list-elem-offset STZ

RTN

@shouldnt-draw-word ( -- flag )

  .list-offset LDZ .list-top LDZ LTH ,&no JCN
  .list-offset LDZ .list-top LDZ .list-height LDZ ADD #01 SUB GTH ,&no JCN
  #00 RTN 

  &no
  #01
RTN

@finish-line ( -> )

  ;get-entry-color JSR2 #02 EQU ,&end JCN
  
  &while
  .Screen/x DEI2
  .Screen/width DEI2 #0048 SUB2
  
  EQU2 ,&end JCN
    #0c .Screen/sprite DEO
    INC-X
    
  ,&while JMP &end

RTN


@draw-cart-name ( -> )

 ;get-entry-color JSR2 #0c NEQ ,&no-store-cart JCN
    ;store-cart JSR2 
  &no-store-cart
  [ ;word
    .Screen/x DEI2
    .Screen/y DEI2
    ;get-entry-color JSR2 ] ;draw-string JSR2
  ;finish-line JSR2

RTN
  

@render-cart-list ( -> )

  #0040 .Screen/x DEO2
  #0028 .Screen/y DEO2

  #00 .list-offset STZ
  .list-len LDZ2 #0000 &while EQU2k ,&end JCN
    ( get a character from the list )
    DUP2 ;list-buf ADD2 LDA
    
    ( if null byte, terminate loop )
    DUP #00 EQU ,&end JCN
    
    ( if not newline, store the character and increment the offsets )
    DUP #0a EQU ,&inc-line JCN
      ;store-char JSR2
    ,&continue JMP ( continue looping )
    
    ( if newline, print the word, increment x, reset y )
    ( clear the word and word offsets, increment the buffer offset )
    &inc-line
      #00 .list-elem-offset LDZ ;word ADD2 STA
      ( if the word isn't in the scroll window, don't draw it )
      ;shouldnt-draw-word JSR2 ,&no-draw JCN
        ;draw-cart-name JSR2
      #0040 .Screen/x DEO2
      INC-Y
      &no-draw
      .list-offset LDZ INC .list-offset STZ
      
      #20 #00 &word_clr EQUk ,&end-clr JCN
        #00 OVR SWP DUP ROT ;word ADD2 STA
      INC ,&word_clr JMP &end-clr POP2
      #00 .list-elem-offset STZ
    &continue INC2 ,&while JMP
  &end .list-offset LDZ #01 SUB .ncarts STZ POP2 POP2
  
RTN

@store-cart ( -> )

  #20 #00 &while EQUk ,&end JCN
    DUP TOS ;word ADD2 LDA
    
    SWP DUP TOS ;cart ADD2
    ROT STH STA
    STHr
  INC ,&while JMP &end POP2
  RTN
RTN

@get-entry-color ( -- colorByte )

  .list-offset LDZ
  .select-index LDZ

  NEQ ,&normal JCN

  ( selected )
    #0c RTN
  &normal
    #02

RTN

@draw-scrollbar ( -> )

  .Screen/width DEI2 #0048 SUB2 .Screen/x DEO2
  #0028 .Screen/y DEO2

  ( draw the trough no matter what )
  ;scrollbar-trough .Screen/addr DEO2
  .list-height LDZ #00
  &while-trough EQUk ,&end-trough JCN
    #81 .Screen/sprite DEO
    INC-Y
  INC ,&while-trough JMP &end-trough POP2

  ( stop here if there is no overflow )
  .ncarts LDZ .list-height LDZ LTH ,&no-handle JCN
  ,&draw-handle JMP
  
  &no-handle
  RTN

  ( if there are more carts than will fit in the view area, draw the handle )
  &draw-handle
  #0028 .Screen/y DEO2
  ( store the number of carts per tile of the scrollbar )
  .ncarts LDZ .list-height LDZ DIV .sb-step STZ

  ( set the length of the scrollbar )
  .list-height LDZ .ncarts LDZ .list-height LDZ SUB .sb-step LDZ DIV SUB .sb-len STZ

  ;scrollbar .Screen/addr DEO2
  #0028 .sb-pos LDZ #30 SFT TOS ADD2 .Screen/y DEO2
  .sb-len LDZ #00 &while-handle EQUk ,&end-handle JCN
    .Screen/y DEI2 .Screen/height DEI2 #0028 SUB2 EQU2 ,&end-handle JCN
    #81 .Screen/sprite DEO
  INC INC-Y ,&while-handle JMP &end-handle POP2
  
RTN

@get-select-idx-by-mouse ( -> )

  .Mouse/wheel DEI #00 EQU ,&no-scroll JCN
  .Mouse/wheel DEI #01 NEQ ,&scroll-down JCN
  ( scroll-up )
  ;try-scroll-up-mouse JSR2
  ,&no-scroll JMP
  
  &scroll-down
  ;try-scroll-down-mouse JSR2
  
  &no-scroll
  .Mouse/x DEI2 #0040 LTH2 ,&done JCN
  .Mouse/x DEI2 .Screen/width DEI2 #0048 SUB2 GTH2 ,&done JCN

  .Mouse/y DEI2 #0028 LTH2 ,&done JCN
  .Mouse/y DEI2 .Screen/height DEI2 #0028 SUB2 GTH2 ,&done JCN
  
  .Mouse/y DEI2 #0028 SUB2 8// TOB .list-top LDZ ADD .select-index STZ

  .Mouse/state DEI #00 EQU ,&no-click JCN
    .select-index LDZ .ncarts GTH ,&no-click JCN
    .state LDZ INC .state STZ
    ;set-button-state-by-key .Controller/vector DEO2
    ;set-button-state-by-mouse .Mouse/vector DEO2
  &no-click
  BRK
  
  &done
  #ff .select-index STZ
  
BRK

@try-scroll-up-mouse ( -> )
  .ncarts LDZ .list-height LDZ LTH ,&no-scroll-up JCN
  .list-top LDZ #00 EQU ,&no-scroll-up JCN
    .list-top LDZ #01 SUB .list-top STZ
    ;update-sb-pos JSR2
  &no-scroll-up
RTN

@try-scroll-down-mouse ( -> )
  .ncarts LDZ .list-height LDZ LTH ,&no-scroll-down JCN
  .list-top LDZ .list-height LDZ ADD .ncarts LDZ #01 ADD EQU ,&no-scroll-down JCN
    .list-top LDZ INC .list-top STZ
    ;update-sb-pos JSR2
  &no-scroll-down
RTN


@try-scroll-up ( -> )
  .select-index LDZ
  DUP .list-top LDZ NEQ ,&no-scroll-up JCN
  .list-top LDZ #00 EQU ,&no-scroll-up JCN
    .list-top LDZ #01 SUB .list-top STZ
    ;update-sb-pos JSR2
  &no-scroll-up
RTN

@try-scroll-down ( -> )
  .select-index LDZ
  DUP .list-top LDZ .list-height LDZ ADD #01 SUB NEQ ,&no-scroll-down JCN
  .list-top LDZ .list-height LDZ ADD .ncarts LDZ #01 ADD EQU ,&no-scroll-down JCN
    .list-top LDZ INC .list-top STZ
    ;update-sb-pos JSR2
  &no-scroll-down
RTN

@update-sb-pos ( -> )

  .list-top LDZ .sb-step LDZ DIV .sb-pos STZ

RTN

@get-select-idx-by-key ( -> )

  .Controller/button DEI
  
  DUP #10 NEQ ,&no-up JCN
    ;try-scroll-up JSR2
    DUP #00 EQU ,&no-dec JCN
      #01 SUB .select-index STZ
      ,&no-up JMP
    &no-dec
      POP
  &no-up
  
  DUP #20 NEQ ,&no-down JCN
    ;try-scroll-down JSR2
    DUP .ncarts LDZ EQU ,&no-inc JCN
      INC .select-index STZ
      ,&no-down JMP
    &no-inc
      POP
  &no-down

  DUP #01 NEQ ,&no-a-btn JCN
    .state LDZ INC .state STZ
    ;set-button-state-by-key .Controller/vector DEO2
    ;set-button-state-by-mouse .Mouse/vector DEO2
  &no-a-btn
  POP

BRK

@set-button-state-by-key ( -> )

  .btn-state LDZ #ff EQU ,&from-null JCN
  .btn-state LDZ #00 EQU ,&from-no JCN
  ( from yes )
    .Controller/button DEI #80 NEQ ,&check-action JCN
    #00 .btn-state STZ
    BRK
  
  &from-no
    .Controller/button DEI #40 NEQ ,&check-action JCN
    #01 .btn-state STZ
    BRK
    
  &from-null
    ( in from left )
    .Controller/button DEI #80 NEQ ,&in-from-right JCN
      #01 .btn-state STZ
      BRK
    &in-from-right
    .Controller/button DEI #40 NEQ ,&check-action JCN
      #00 .btn-state STZ
      BRK
      
  &check-action
    .Controller/button DEI #00 EQU ,&no-action JCN
      ( check A button )
      .Controller/button DEI #01 NEQ ,&check-b-button JCN
        ( A on yes )
        .btn-state LDZ #01 NEQ ,&a-on-no JCN
          ;capture-input JSR2
          ;load-cart JSR2
          BRK
        &a-on-no
        .btn-state LDZ #00 NEQ ,&no-action JCN
          ;get-select-idx-by-mouse .Mouse/vector DEO2
          ;get-select-idx-by-key .Controller/vector DEO2
          #04 .state STZ
          BRK
        
      &check-b-button
      .Controller/button DEI #02 NEQ ,&no-action JCN
        ;get-select-idx-by-mouse .Mouse/vector DEO2
        ;get-select-idx-by-key .Controller/vector DEO2
        #04 .state STZ
  &no-action

BRK

@set-button-state-by-mouse ( -> )

  ( if not in the vertical range of the buttons, quit early )
  .Mouse/y DEI2 .Screen/height DEI2 #001c SUB2 LTH2 ,&not-no JCN
  .Mouse/y DEI2 .Screen/height DEI2 #000c SUB2 GTH2 ,&not-no JCN
  

  .Mouse/x DEI2 CENTER-X #0030 SUB2 LTH2 ,&not-yes JCN
  .Mouse/x DEI2 CENTER-X GTH2 ,&not-yes JCN
  #01 .btn-state STZ
  ,&check-click JMP
  
  &not-yes

  .Mouse/x DEI2 CENTER-X LTH2 ,&not-no JCN
  .Mouse/x DEI2 CENTER-X #0030 ADD2 GTH2 ,&not-no JCN
  #00 .btn-state STZ
  ,&check-click JMP

  &not-no
  #ff .btn-state STZ BRK

  &check-click
  .Mouse/state DEI #00 EQU ,&no-click JCN
    .btn-state LDZ #00 NEQ ,&state-load JCN
      ;get-select-idx-by-mouse .Mouse/vector DEO2
      ;get-select-idx-by-key .Controller/vector DEO2
      #04 .state STZ
      BRK
    &state-load
      ;capture-input JSR2
      ;load-cart JSR2
  &no-click

BRK

@button-color ( bit -- sprite )

  ,&get-color-yes JCN

  ( get color no )
  .btn-state LDZ #ff EQU ,&no-inactive JCN
  .btn-state LDZ #01 EQU ,&no-inactive JCN
  ( active )
    ;no-btn-active RTN

  &no-inactive
    ;no-btn RTN
  
  
  &get-color-yes
  .btn-state LDZ #ff EQU ,&yes-inactive JCN
  .btn-state LDZ #00 EQU ,&yes-inactive JCN
    ( active )
    ;yes-btn-active RTN

  &yes-inactive
    ;yes-btn 

RTN

@draw-confirm-buttons ( -> )

  ( yes )
  .Screen/height DEI2 #001c SUB2 .Screen/y DEO2
  CENTER-X #0030 SUB2 .Screen/x DEO2

  #00c0 #0000 &while-yes EQU2k ,&end-yes JCN
    DUP2 [ #01 ;button-color JSR2 ] ADD2 .Screen/addr DEO2
    #81 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0060 NEQ2 ,&no-inc-y JCN
      CENTER-X #0030 SUB2 .Screen/x DEO2
      INC-Y
    &no-inc-y
  #0010 ADD2 ,&while-yes JMP &end-yes POP2 POP2
  
  ( no )
  .Screen/height DEI2 #001c SUB2 .Screen/y DEO2
  CENTER-X .Screen/x DEO2

  #00c0 #0000 &while-no EQU2k ,&end-no JCN
    DUP2 [ #00 ;button-color JSR2 ] ADD2 .Screen/addr DEO2
    #81 .Screen/sprite DEO INC-X
    
    NEXT-TILE #0060 NEQ2 ,&no-inc-y-no JCN
      CENTER-X .Screen/x DEO2
      INC-Y
    &no-inc-y-no
  #0010 ADD2 ,&while-no JMP &end-no POP2 POP2

RTN

@load-cart ( -> )

  .state LDZ INC .state STZ
  
  ( send it! ) 
  #0020 .File/length DEO2
  #0001 .File/offset-ls DEO2
  ;ctl-file .File/name DEO2
  ;load-cmd .File/save DEO2

  ;slot-file ;load-rom JSR2
RTN

@load-rom ( filename* -- )
(
	Attempts to load the ROM from filename* and executes it. If the file exists
	and has non-zero length, this function does not return, because the new ROM
	is executing in its place.

	The screen and both stacks are cleared and all the device vectors are
	written to zero as a convenience. All other device bytes are left
	untouched, so they could introduce a device state to the next ROM that
	it's not expecting.
)

	.File/name DEO2
	#0000 .File/offset-hs DEO2
	#0000 .File/offset-ls DEO2

	( return if file can't be found, or zero length )
	#0001 .File/length DEO2
	;&tmp .File/load DEO2
	.File/success DEI2 ORA JMP JMP2r

	( clear wst )
	#ab
	&wst-loop
	POP
	.System/wst STH DEIr STHr ,&wst-loop JCN

	( clear rst )
	LITr ab
	&rst-loop
	POPr
	.System/rst DEI ,&rst-loop JCN

	( clear screen )
	#01 .Screen/auto DEO
	#0000 .Screen/y DEO2
	.Screen/width DEI2 #0007 ADD2 #03 SFT2 #ffff MUL2 STH2
	&screen-yloop
		#0000 .Screen/x DEO2
		STH2kr
		&screen-xloop-bg
			#00 .Screen/sprite DEO
			INC2
			ORAk ,&screen-xloop-bg JCN
		POP2
		#0000 .Screen/x DEO2
		STH2kr
		&screen-xloop-fg
			#40 .Screen/sprite DEO
			INC2
			ORAk ,&screen-xloop-fg JCN
		POP2
		.Screen/y DEI2 #0008 ADD2
		DUP2 .Screen/y DEO2
		.Screen/height DEI2 LTH2 ,&screen-yloop JCN
	POP2r
	#00 .Screen/auto DEO

	( reset device vectors )
	LIT2r 0000 #00
	&device-vector-loop
	DUP2r STHk DEO2r
	#10 ADD
	DUP ,&device-vector-loop JCN
	POP POP2r

	( copy the zero-page-loader into f0-ff )
	;&zero-page-loader LITr f0
	&copy-loop
	LDAk STHkr STZ
	INC2 INCr
	STHkr ,&copy-loop JCN
	POP2 ( leave 00 on return stack )

	( prepare the stack for the zero-page-loader )
	( the more we prepare here in advance, the less we'll have to overwrite )
	STHkr #00fe ( arguments for STZ2 at ff )
	STHkr ( argument for JMP at fe (carry on) )
	DUPk #fcfe ( arguments for STZ2 at fd and JMP (repeat) )
	OVR2 #fafe ( arguments for STZ2 at fd and JMP (repeat) )
	OVR2 #f8fe ( arguments for STZ2 at fd and JMP (repeat) )
	OVR2 #f6fe ( arguments for STZ2 at fd and JMP (repeat) )
	OVR2 #f401 ( arguments for STZ2 at fd, plus an extra 01 )
	STHkr ( first argument for ADD2 )
	.File/success ( argument for DEI2 )
	#0100 .File/load ( arguments for DEO2 )
	#ff00 .File/length DEO2
	#00f0 JMP2

	&zero-page-loader
	( f0 ) DEO2
	( f1 ) DEI2
	( f2 ) ADD2
	( f3 ) &loop DUPr
	( f4 ) STH2k
	( f5 ) STAr
	( f6 ) INC2
	( f7 ) NEQ2k
	( f8 ) ,&loop
	( f9 )
	( fa ) JCN
	( fb ) POPr
	( fc ) POP2
	( fd ) STZ2 ( deletes f4-fd through looping )
	( fe ) JMP
	( ff ) STZ2 ( deletes fe-ff )

	&tmp $1

@capture-input ( -> )

  ;no-instr .Mouse/vector DEO2
  ;no-instr .Controller/vector DEO2

RTN

@no-instr BRK

( constants )
@spritesheet "xrxs.chr 00
@fontsheet "zz.chr 00
@carts-file "n/carts 00
@slot-file "n/slot 00
@ctl-file "n/ctl 00

@title-loadCart "Select 20 "A 20 "Cartridge 00
@title-confirmCart "Load 20 "This 20 "Cartridge? 00

@load-cmd "load 20
@cart $32

( sprites )
@blank $16
@uxn-logo [
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    00 00 00 00 00 00 00 00 00 09 1b 3f 1e 18 18 18 
  00 00 00 00 00 00 00 00 00 e0 f0 38 1c 0c 0c 0c    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    00 00 00 00 00 00 00 00 18 18 18 18 18 18 18 3e 
  00 00 00 00 00 00 00 00 0c 0c 0c 0c 0c 0c 1e 00    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
  00 00 00 00 00 00 00 00 00 78 30 30 30 30 30 30    00 00 00 00 00 00 00 00 7c 18 18 18 18 18 18 18 
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
  00 00 00 00 00 00 00 00 30 30 30 38 1c 0f 07 00    00 00 00 00 00 00 00 00 18 18 38 78 fc d8 90 00 
  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
]

@xrxs-logo [
   00 00 00 00 00 00 00 00 00 60 70 38 1c 0e 07 03    00 00 00 00 00 00 00 00 00 00 06 0c 18 30 60 c0 
   00 00 00 00 00 00 00 00 00 01 63 36 1c 0c 0c 0c    00 00 00 00 00 00 00 00 00 e0 f0 1c 0c 00 00 00 
   00 00 00 00 00 00 00 00 03 06 0c 18 30 60 00 00    00 00 00 00 00 00 00 00 c0 e0 70 38 1c 0e 06 00 
   00 00 00 00 00 00 00 00 0c 0c 0c 0c 0c 1c 3e 00    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
   00 00 00 00 00 00 00 00 00 60 70 38 1c 0e 07 03    00 00 00 00 00 00 00 00 00 00 06 0c 18 30 60 c0 
   00 00 00 00 00 00 00 00 00 03 07 0e 18 18 18 1f    00 00 00 00 00 00 00 00 00 c0 f0 78 08 00 00 e0 
   00 00 00 00 00 00 00 00 03 06 0c 18 30 60 00 00    00 00 00 00 00 00 00 00 c0 e0 70 38 1c 0e 06 00 
   00 00 00 00 00 00 00 00 07 00 00 10 1e 0f 03 00    00 00 00 00 00 00 00 00 f8 18 18 18 70 e0 c0 00 
]

@yes-btn [
  ff f8 f0 e0 e0 e1 e2 e2 00 07 08 10 10 11 12 12    ff 00 00 00 e0 10 08 08 00 ff 00 00 e0 10 08 08 
  ff 00 00 00 00 00 00 00 00 ff 00 00 82 82 44 38    ff 00 00 00 00 00 00 00 00 ff 00 00 fe 80 80 f8 
  ff 00 00 00 00 00 00 00 00 ff 00 00 7c 82 80 7c    ff 3f 1f 0f 0f 0f 0f 0f 00 c0 20 10 10 10 10 10 
  e2 e1 e0 e0 e0 f0 f8 ff 12 11 10 10 10 08 07 00    08 10 e0 00 00 00 00 ff 08 10 e0 00 00 00 ff 00 
  00 00 00 00 00 00 00 ff 10 10 10 00 00 00 ff 00    00 00 00 00 00 00 00 ff 80 80 fe 00 00 00 ff 00 
  00 00 00 00 00 00 00 ff 02 82 7c 00 00 00 ff 00    0f 0f 0f 0f 0f 1f 3f ff 10 10 10 10 10 20 c0 00 
]

@no-btn [
  ff f8 f0 e0 e2 e1 e0 e0 00 07 08 10 12 11 10 10    ff 00 00 00 08 10 a0 40 00 ff 00 00 08 10 a0 40 
  ff 00 00 00 00 00 00 00 00 ff 00 00 08 0c 0a 09    ff 00 00 00 00 00 00 00 00 ff 00 00 27 28 28 28 
  ff 00 00 00 00 00 00 00 00 ff 00 00 c0 20 20 20    ff 3f 1f 0f 0f 0f 0f 0f 00 c0 20 10 10 10 10 10 
  e0 e1 e2 e0 e0 f0 f8 ff 10 11 12 10 10 08 07 00    a0 10 08 00 00 00 00 ff a0 10 08 00 00 00 ff 00 
  00 00 00 00 00 00 00 ff 08 08 08 00 00 00 ff 00    00 00 00 00 00 00 00 ff a8 68 27 00 00 00 ff 00 
  00 00 00 00 00 00 00 ff 20 20 c0 00 00 00 ff 00    0f 0f 0f 0f 0f 1f 3f ff 10 10 10 10 10 20 c0 00 
]

@yes-btn-active [
 ff ff f8 f0 f0 f1 f2 f2 00 07 08 10 10 11 12 12    ff ff 00 00 e0 10 08 08 00 ff 00 00 e0 10 08 08 
 ff ff 00 00 00 00 00 00 00 ff 00 00 82 82 44 38    ff ff 00 00 00 00 00 00 00 ff 00 00 fe 80 80 f8 
 ff ff 00 00 00 00 00 00 00 ff 00 00 7c 82 80 7c    ff ff 3f 1f 1f 1f 1f 1f 00 c0 20 10 10 10 10 10 
 f2 f1 f0 f0 f0 f8 ff ff 12 11 10 10 10 08 07 00    08 10 e0 00 00 00 ff ff 08 10 e0 00 00 00 ff 00 
 00 00 00 00 00 00 ff ff 10 10 10 00 00 00 ff 00    00 00 00 00 00 00 ff ff 80 80 fe 00 00 00 ff 00 
 00 00 00 00 00 00 ff ff 02 82 7c 00 00 00 ff 00    1f 1f 1f 1f 1f 3f ff ff 10 10 10 10 10 20 c0 00 
]

@no-btn-active [
  ff ff f8 f0 f2 f1 f0 f0 00 07 08 10 12 11 10 10    ff ff 00 00 08 10 a0 40 00 ff 00 00 08 10 a0 40 
  ff ff 00 00 00 00 00 00 00 ff 00 00 08 0c 0a 09    ff ff 00 00 00 00 00 00 00 ff 00 00 27 28 28 28 
  ff ff 00 00 00 00 00 00 00 ff 00 00 c0 20 20 20    ff ff 3f 1f 1f 1f 1f 1f 00 c0 20 10 10 10 10 10 
  f0 f1 f2 f0 f0 f8 ff ff 10 11 12 10 10 08 07 00    a0 10 08 00 00 00 ff ff a0 10 08 00 00 00 ff 00 
  00 00 00 00 00 00 ff ff 08 08 08 00 00 00 ff 00    00 00 00 00 00 00 ff ff a8 68 27 00 00 00 ff 00 
  00 00 00 00 00 00 ff ff 20 20 c0 00 00 00 ff 00    1f 1f 1f 1f 1f 3f ff ff 10 10 10 10 10 20 c0 00 
]

@scrollbar [
  ff ff ff ff ff ff ff ff 3c 3c 3c 3c 3c 3c 3c 3c 
]

@scrollbar-trough [
  c3 c3 c3 c3 c3 c3 c3 c3 28 14 28 14 28 14 28 14
]

@cursor [
  80c0 e0f0 f8e0 1000
 ]

@font [
  00 00 00 00 00 00 00 00 00 18 18 18 08 00 08 00    00 14 14 00 00 00 00 00 00 24 7e 24 24 7e 24 00 
  00 10 3c 50 38 14 78 10 00 00 44 08 10 20 44 00    00 18 20 32 2c 24 1a 00 00 18 10 20 00 00 00 00 
  00 04 08 08 08 08 04 00 00 20 10 10 10 10 20 00    00 00 44 28 10 28 44 00 00 00 10 10 7c 10 10 00 
  00 00 00 00 00 0c 08 10 00 00 00 00 3e 00 00 00    00 00 00 00 00 0c 0c 00 00 02 04 08 10 20 40 00 
  00 38 44 54 54 44 38 00 00 30 10 10 10 10 38 00    00 38 44 04 38 40 7c 00 00 38 44 18 04 44 38 00 
  00 08 18 28 48 7c 08 00 00 7c 40 78 04 44 38 00    00 38 40 78 44 44 38 00 00 7c 04 08 10 10 10 00 
  00 38 44 38 44 44 38 00 00 38 44 44 3c 04 38 00    00 18 18 00 00 18 18 00 00 18 18 00 00 18 10 20 
  00 00 08 10 20 10 08 00 00 00 00 3e 00 3e 00 00    00 00 10 08 04 08 10 00 00 38 44 1c 10 00 10 00 
  00 38 44 5c 58 40 3c 00 00 10 28 44 7c 44 44 00    00 78 44 78 44 44 78 00 00 38 44 40 40 44 38 00 
  00 78 44 44 44 44 78 00 00 7c 40 7c 40 40 7c 00    00 7c 40 7c 40 40 40 00 00 38 44 40 4c 44 3c 00 
  00 44 44 7c 44 44 44 00 00 7c 10 10 10 10 7c 00    00 7c 08 08 48 48 30 00 00 44 48 70 48 44 44 00 
  00 40 40 40 40 40 7c 00 00 44 6c 7c 54 44 44 00    00 44 64 74 5c 4c 44 00 00 38 44 44 44 44 38 00 
  00 78 44 44 78 40 40 00 00 38 44 44 4c 4c 3e 00    00 78 44 44 78 44 44 00 00 3c 40 38 04 04 78 00 
  00 7c 10 10 10 10 10 00 00 44 44 44 44 44 3c 00    00 44 44 28 28 10 10 00 00 44 44 44 54 6c 44 00 
  00 44 44 38 38 44 44 00 00 44 44 28 10 10 10 00    00 7c 04 18 30 40 7c 00 00 3c 30 30 30 30 3c 00 
  00 40 20 10 08 04 02 00 00 3c 0c 0c 0c 0c 3c 00    00 10 38 6c 00 00 00 00 00 00 00 00 00 00 7e 00 
  00 18 08 04 00 00 00 00 00 00 38 04 3c 44 3c 00    00 40 40 78 44 44 78 00 00 00 38 44 40 44 38 00 
  00 04 04 3c 44 44 3c 00 00 00 38 44 7c 40 3c 00    00 1c 20 78 20 20 20 00 00 00 3c 44 3c 04 44 38 
  00 40 40 78 44 44 44 00 00 30 00 70 10 10 18 00    00 0c 00 3c 04 04 44 38 00 00 44 48 70 48 44 00 
  00 70 10 10 10 10 1c 00 00 00 44 6c 7c 54 44 00    00 00 78 44 44 44 44 00 00 00 38 44 44 44 38 00 
  00 00 78 44 44 78 40 40 00 00 3c 44 44 3d 06 04    00 00 4c 50 60 40 40 00 00 00 3c 40 38 04 78 00 
  00 20 78 20 20 24 38 00 00 00 44 44 44 44 3c 00    00 00 44 44 28 28 10 00 00 00 44 44 54 7c 28 00 
  00 00 44 28 10 28 44 00 00 00 44 44 3c 04 78 00    00 00 7c 04 38 40 7c 00 00 1e 10 10 10 00 00 00 
  00 10 10 10 10 10 10 00 00 00 00 08 08 08 78 00    00 00 00 32 4c 00 00 00 3c 42 99 a1 a1 99 42 3c 
]

( big data )
@word [ #0000 #0000 #0000 #0000
        #0000 #0000 #0000 #0000
        #0000 #0000 #0000 #0000
        #0000 #0000 #0000 #0000 ]
@list-buf $8192