Add a spin loop that does something

Namely, poke register $2100 to set the brightness

tic_tac.asm

@@ -5,6 +5,30 @@
 .org 0
 .section "Vblank"
 
+.MACRO Spin_Loop ARGS XCOUNT
+
+; it is fucktarded that this macro doesn't work properly with immediates
+;ldx XCOUNT
+ldx #$04
+lvl3\@:
+    lda #$ff
+    lvl2\@:
+        xba
+        lda #$ff
+        lvl1\@:
+            dea
+            cmp #$00
+            bne lvl1\@
+        xba
+        dea
+        cmp #$00
+        bne lvl2\@
+    dex
+    txa
+    cmp #$00
+    bne lvl3\@
+.ENDM
+
 VBlank:
     rti
 
@@ -118,7 +142,7 @@ stx $2118 ;data for VRAM write register
 ; set up the screen
 
 lda #%00110000 ; 16x16 tiles, mode 0
-sta $2105
+sta $2105     ; $2105 is the mode for bg mode + tile size
 
 lda #%01000000 ; data starts from $4000
 sta $2107      ; for bg1
@@ -152,19 +176,20 @@ sta $2100
 lda #%10000001  ; enable NMI and joypads
 sta $4200
 
+    Spin_Loop
 
-
-;sep #$30        ; get 8-bit registers
-;stz $2121       ; write to CGRAM from $0
-;lda #%10000000  ; this is
-;ldx #%00111100  ; a green color
-;sta $2122       ; write it
-;stx $2122       ; to CGRAM
-;lda #%00001111  ; turn on screen
-;sta $2100       ; here
-
+lda #%00000011
+sta $2100
 
 mainloop:
+    Spin_Loop
+    lda #%00000011
+    sta $2100
+
+    Spin_Loop
+    lda #$0f
+    sta $2100
+
     jmp mainloop
 
 .ENDS