;license:MIT
;(c) 2019 by 4am
;
!cpu 6502
!to "build/FX.INDEXED/SOFT.L",plain
*=$6000

y = $fc
row = $fd
col = $fe
counter = $ff

         !source "src/fx/macros.a"
         !source "src/constants.a"

         lda   #(40+7-1)  ; columns + blocks per row - 1
         sta   counter

         lda   #39
         sta   col
ColLoop
         lda   #23
         sta   row
RowLoop
         ; [speedopt] calculate HGR base addresses once per row
         lda   row
         asl
         asl
         asl
         +HGR_CALC

         ldy   col
         +IS_Y_OFFSCREEN
         bcs   @block2

         ; [speedopt] HGRBlockCopyWithMask but hardcoded for this block's masks
         ldx   #7
         clc
-
         +COPY_BIT $3c, $26, copymasks1
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         ; [speedopt] reset HGR base addresses instead of recalculating them from scratch
         +RESET_HGR_CALC
@block2
         iny
         +IS_Y_OFFSCREEN
         bcs   @block3

         ldx   #7
         clc
-
         +COPY_BIT $3c, $26, copymasks2
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         +RESET_HGR_CALC
@block3
         iny
         +IS_Y_OFFSCREEN
         bcs   @block4

         ldx   #7
         clc
-
         +COPY_BIT $3c, $26, copymasks3
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         +RESET_HGR_CALC
@block4
         iny
         +IS_Y_OFFSCREEN
         bcs   @block5

         ldx   #7
         clc
-
         +COPY_BIT $3c, $26, copymasks4
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         +RESET_HGR_CALC
@block5
         iny
         +IS_Y_OFFSCREEN
         bcs   @block6

         ldx   #7
         clc
-
         +COPY_BIT $3c, $26, copymasks5
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         +RESET_HGR_CALC
@block6
         iny
         +IS_Y_OFFSCREEN
         bcs   @block7

         ldx   #7
         clc
-
         +COPY_BIT $3c, $26, copymasks6
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         +RESET_HGR_CALC
@block7
         iny
         +IS_Y_OFFSCREEN
         bcs   @nextrow

         ; [speedopt] HGRBlockCopy but inlined
         ldx   #7
         clc
-        lda   ($3c),y
         sta   ($26),y
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   -

         ; don't need RESET_HGR_CALC here because we're done with this row
@nextrow
         dec   row
         +LBPL RowLoop
         lda   $c000
         bmi   @exit
         dec   col
         dec   counter
         +LBNE ColLoop
@exit    rts

copymasks1
         !byte %10000000
         !byte %10000000
         !byte %10000000
         !byte %10001000
         !byte %10001000
         !byte %10000000
         !byte %10000000
         !byte %10000000
copymasks2
         !byte %10000000
         !byte %10000000
         !byte %10010100
         !byte %10001000
         !byte %10001000
         !byte %10010100
         !byte %10000000
         !byte %10000000
copymasks3
         !byte %10000000
         !byte %10000000
         !byte %10011100
         !byte %10011100
         !byte %10011100
         !byte %10011100
         !byte %10000000
         !byte %10000000
copymasks4
         !byte %10000000
         !byte %10101010
         !byte %10011100
         !byte %10111110
         !byte %10011100
         !byte %10011100
         !byte %10101010
         !byte %10000000
copymasks5
         !byte %10000000
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10000000
copymasks6
         !byte %11010101
         !byte %10111110
         !byte %11111111
         !byte %10111110
         !byte %11111111
         !byte %10111110
         !byte %10111110
         !byte %11010101