Enemy Coordinates Compared to Player's

; ZEROPAGE
nmi_num:    .res 1
temp_16bit_1:   .res 2
temp_16bit_2:   .res 2
loop_addy:  .res 2
p_floor:    .res 1
p_x_pos:    .res 1
p_y_pos:    .res 1

; CONSTANTS
enemy_amount_on_floors  = $500

floors_lo:
    .byte <floor0_big, <floor1_big, <floor2_big, <floor3_big
floors_hi:
    .byte >floor0_big, >floor1_big, >floor2_big, >floor3_big
enemy_y_coords_lo:
    .byte <floor0_enemy_y, <floor1_enemy_y, <floor2_enemy_y, <floor3_enemy_y
enemy_y_coords_hi:
    .byte >floor0_enemy_y, >floor1_enemy_y, >floor2_enemy_y, >floor3_enemy_y
enemy_x_coords_lo:
    .byte <floor0_enemy_x, <floor1_enemy_x, <floor2_enemy_x, <floor3_enemy_x
enemy_x_coords_hi:
    .byte >floor0_enemy_x, >floor1_enemy_x, >floor2_enemy_x, >floor3_enemy_x

; Number of enemy encounters per floor +1. Plus one so
;  the routine will run entirely through all and exit
enemy_amount_on_floors:
    .byte 21,26,31,36

; Dummy data for testing
floor0_enemy_y:
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor1_enemy_y:
    .byte 46,44,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor2_enemy_y:
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor3_enemy_y:
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor0_enemy_x:
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor1_enemy_x:
    .byte 04,04,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor2_enemy_x:
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
floor3_enemy_x:
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00
    .byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00

; Run this AFTER the screen is done loading to find out
;  if there is an enemy on the coordinate the player has
;  landed on
enemy_test_coordinate:
    ldx p_floor                 ; Get floor player is on
    lda enemy_y_coords_lo, x            ; Get correct table of enemy Y pos
    sta temp_16bit_1+0              ;
    lda enemy_y_coords_hi, x            ;
    sta temp_16bit_1+1              ;
    lda enemy_x_coords_lo, x            ; Get correct table of enemy X pos
    sta temp_16bit_2+0              ;
    lda enemy_x_coords_hi, x            ;
    sta temp_16bit_2+1              ;
    ldy #00                     ; Set up Y register
@test_y:                        ;
    lda (temp_16bit_1), y               ; Test if enemy Y pos == player Y pos
    cmp p_y_pos                 ;  and if so...
    bne :+                      ;
        lda (temp_16bit_2), y           ; Test if enemy X pos == player X pos
        cmp p_x_pos             ;  and if so...
        bne :+                  ;
            lda enemy_present, y        ; Test if enemy at that coord has been
            beq :+              ;  defeated yet or not through RAM table
                lda #<loop_nothing  ; Do stuff if enemies are present
                sta loop_addy+0     ;
                lda #>loop_nothing  ;
                sta loop_addy+1     ;
                rts         ;
:   iny                     ; Increment the Y register and stick it
    tya                     ;  in A to compare the amount of enemies
    cmp enemy_amount_on_floors, x           ;  on the floor in order to escape the
    bne @test_y                 ;  routine
    rts                     ;

loop_nothing:
    jmp end_loop

loop:
    jmp (loop_addy)
end_loop:
    jsr nmi_wait
    jmp loop

nmi_wait:
    lda nmi_num
:   cmp nmi_num
    beq :-
    rts