Column updating

plat.s

@@ -82,6 +82,7 @@ nmi_count:      .res 1
 nmi_ready:      .res 1
 nmt_update_len: .res 1
 nmt_column:     .res 1
+nmt_update_frame: .res 1
 scroll_x:       .res 1
 scroll_y:       .res 1
 scroll_nmt:     .res 1
@@ -155,59 +156,43 @@ nmi:
     sta $2000
 
     ldy #0
+    ldx #0
     @nmt_update_loop:
-        lda #6
+        lda nmt_update_frame
-        jsr mul_y
+        cmp #0
-        tax
+        bne :+
+            lda nmt_update+0, X
+            sta $2006
+            lda nmt_update+1, X
+            sta $2006
 
-        lda $2002
+            lda nmt_update+2, X
+            sta $2007
+            lda nmt_update+3, X
+            sta $2007
 
-        lda nmt_update+0, X
+            jmp :++
-        sta $2006
+        :
-        lda nmt_update+1, X
+            lda nmt_update+0, X
-        sta $2006
+            sta $2006
+            lda nmt_update+1, X
+            clc
+            adc #32
+            sta $2006
 
-        lda nmt_update+2, X
+            lda nmt_update+4, X
-        sta $2007
+            sta $2007
-        lda nmt_update+3, X
+            lda nmt_update+5, X
-        sta $2007
+            sta $2007
+        :
 
 
-        lda $2002
+        inx
-
+        inx
-        lda nmt_update+0, X
+        inx
-        sta $2006
+        inx
-        lda nmt_update+1, X
+        inx
-        clc
+        inx
-        adc #32
-        sta $2006
-
-        lda nmt_update+4, X
-        sta $2007
-        lda nmt_update+5, X
-        sta $2007
-
-
-;       lda $2002
-;       lda #$20
-;       sta $2006
-
-;       lda nmt_update, Y
-;       sec
-;       rol
-;       sta $2006
-
-;       ldx nmt_update
-;       lda level, X
-;       and #%01111111
-;       ldx #5
-;       jsr mul_x
-;       tax
-;       
-;       lda metatiles+1, X
-;       sta $2007
-;       lda metatiles+3, X
-;       sta $2007
 
         iny
         cpy nmt_update_len
@@ -216,8 +201,14 @@ nmi:
     lda PPUCTRL_default
     sta $2000
 
-    lda #0
+    inc nmt_update_frame
-    sta nmt_update_len
+    lda nmt_update_frame
+    cmp #2
+    bne :+
+        lda #0
+        sta nmt_update_frame
+        sta nmt_update_len
+    :
 @scroll:
     lda scroll_nmt
     and #%00000011
@@ -428,6 +419,8 @@ last_frame_moving: .res 1
 
 tile_update_pos_r: .res 1
 
+pointer:           .res 2
+
 .segment "BSS"
 level:      .res 240
 level2:     .res 240
@@ -1495,15 +1488,54 @@ check_column_update:
     rts
 
 update_nmt_column:
+    ; X represents the row of the current tile being updated
     ldx #0
-    :
+    @row_loop:
+        lda tile_update_pos_r
+        clc
+        adc #8
+        sta var_n
+
+        ; Nametable base
+        lda #$20
+        sta var_o
+
+        lda #<level
+        sta pointer
+        lda #>level
+        sta pointer+1
+
+
+        lda var_n
+        and #%00010000
+        cmp #0
+        beq:+
+            lda pointer
+            clc
+            adc #240
+            sta pointer
+
+            lda pointer+1
+            adc #0
+            sta pointer+1
+
+            lda #$24
+            sta var_o
+        :
+
+            lda var_n
+        and #%00001111
+        sta var_p
+
+
         lda #16
         jsr mul_x
         clc
-        adc tile_update_pos_r
+        adc var_p
         tay
-        lda #%10000001
+        ; Specifies what tile gets written to the column
-        sta level, Y
+        lda #%10000011
+        sta (pointer), Y
 
         and #%01111111
         ldy #5
@@ -1511,6 +1543,7 @@ update_nmt_column:
         tay
 
 
+        ; Preserve X
         txa
         pha
 
@@ -1528,21 +1561,23 @@ update_nmt_column:
         sta nmt_update+5, X
 
 
+        ; Recover X (to Y)
         pla
         tay
 
         lsr
         lsr
+        ; Add nametable base
         clc
-        adc #$20
+        adc var_o
         sta nmt_update+0, X
 
         lda #64
         jsr mul_y
         clc
-        adc tile_update_pos_r
+        adc var_p
         clc
-        adc tile_update_pos_r
+        adc var_p
         sta nmt_update+1, X
 
 
@@ -1552,10 +1587,12 @@ update_nmt_column:
 
         inx
         cpx #15
-        bne :-
+        beq :+
+            jmp @row_loop
+        :
 
 
-    lda #15
+    lda #1
     sta nmt_update_len
 
     rts