4cade/src/fx/fx.dhgr.soft.diagonal.a

;license:MIT
;(c) 2019-2020 by 4am
;
!cpu 6502
!to "build/FX/DHGR.SOFT.DIAG",plain
*=$6000

src = $F0
dst = $F2
row = $FD
col = $FE
counter = $FF

!macro INC_HGR_HI_BY .blocks {
;        lda   dst+1
         adc   #(.blocks*4)
         sta   dst+1
         eor   #$60
         sta   src+1
}

!macro SET_HGR_HI {
         sta   src+1
         eor   #$60
         sta   dst+1
}

!macro RESET_HGR_HI {
         txa
         +SET_HGR_HI
}

!macro RESET_HGR_HI_AND_INC_BY .blocks {
         txa
         adc   #(.blocks*4)
         sta   src+1
         eor   #$60
         sta   dst+1
}

; note: .copymask is an immediate value, not an indexed array or a memory address
!macro COPY_WITH_MASK_IMM .copymask {
         lda   (src), y
         eor   (dst), y              ; merge source and destination bits
         and   #.copymask            ; isolate the bits to replace, zero the rest
         eor   (dst), y              ; unmerge source and destination bits, leaves 'to keep' destination bits intact
         sta   (dst), y              ; write the result
}
!macro COPY_WITH_MASK_IMM_AND_INC .copymask {
         +COPY_WITH_MASK_IMM .copymask
         lda   dst+1
         +INC_HGR_HI_BY 1
}

!macro COPY_BYTE {
         lda   (src), y
         sta   (dst), y
}

!macro COPY_BYTE_AND_INC {
         +COPY_BYTE
         lda   dst+1
         +INC_HGR_HI_BY 1
}

         !source "src/fx/macros.a"
         !source "src/fx/fx.dhgr.common.a"

         +COPY_TO_AUXMEM $60, $07

         lda   #(40+24+7-1) ; columns + rows + blocks per row - 1
         sta   counter

         lda   #39
         sta   col
ColLoop
         lda   #23
         sta   row
         ldy   col
RowLoop
         ldx   row
         lda   hgrrowlo, x
         sta   src
         sta   dst
         lda   hgrrowhi, x
         tax
         +SET_HGR_HI

         +BRANCH_IF_Y_IS_OFFSCREEN @block2
         +INC_HGR_HI_BY 3
         +COPY_WITH_MASK_IMM_AND_INC %10000001
         +COPY_WITH_MASK_IMM         %10000001
@block2
         iny
         +BRANCH_IF_Y_IS_OFFSCREEN @block3
         +RESET_HGR_HI_AND_INC_BY 2
         +COPY_WITH_MASK_IMM_AND_INC %10000110
         +COPY_WITH_MASK_IMM_AND_INC %10000001
         +COPY_WITH_MASK_IMM_AND_INC %10000001
         +COPY_WITH_MASK_IMM         %10010110
@block3
         iny
         +BRANCH_IF_Y_IS_OFFSCREEN @block4
         +RESET_HGR_HI_AND_INC_BY 2
         +COPY_WITH_MASK_IMM_AND_INC %10000111
         +COPY_WITH_MASK_IMM_AND_INC %10000111
         +COPY_WITH_MASK_IMM_AND_INC %10000111
         +COPY_WITH_MASK_IMM         %10000111
@block4
         iny
         +BRANCH_IF_Y_IS_OFFSCREEN @block5
         +RESET_HGR_HI_AND_INC_BY 1
         +COPY_WITH_MASK_IMM_AND_INC %10011001
         +COPY_WITH_MASK_IMM_AND_INC %10000001
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM_AND_INC %10000111
         +COPY_WITH_MASK_IMM_AND_INC %10000111
         +COPY_WITH_MASK_IMM         %10011001
@block5
         iny
         +BRANCH_IF_Y_IS_OFFSCREEN @block6
         +RESET_HGR_HI_AND_INC_BY 1
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM         %10011111
@block6
         iny
         +LONG_BRANCH_IF_Y_IS_OFFSCREEN @block7
         +RESET_HGR_HI
         +COPY_WITH_MASK_IMM_AND_INC %11100110
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_BYTE_AND_INC
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_BYTE_AND_INC
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM_AND_INC %10011111
         +COPY_WITH_MASK_IMM         %11100110
@block7
         iny
         +BRANCH_IF_Y_IS_OFFSCREEN @switchtoaux
         +RESET_HGR_HI
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE
@switchtoaux
         sta   $C003
         sta   $C005
         +BRANCH_IF_Y_IS_OFFSCREEN @block6_aux
         +RESET_HGR_HI
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE_AND_INC
         +COPY_BYTE
@block6_aux
         dey
         +LONG_BRANCH_IF_Y_IS_OFFSCREEN @block5_aux
         +RESET_HGR_HI
         +COPY_WITH_MASK_IMM_AND_INC %10110011
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_BYTE_AND_INC
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_BYTE_AND_INC
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM         %10110011
@block5_aux
         dey
         +BRANCH_IF_Y_IS_OFFSCREEN @block4_aux
         +RESET_HGR_HI_AND_INC_BY 1
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM         %11111100
@block4_aux
         dey
         +BRANCH_IF_Y_IS_OFFSCREEN @block3_aux
         +RESET_HGR_HI_AND_INC_BY 1
         +COPY_WITH_MASK_IMM_AND_INC %11001100
         +COPY_WITH_MASK_IMM_AND_INC %11110000
         +COPY_WITH_MASK_IMM_AND_INC %11111100
         +COPY_WITH_MASK_IMM_AND_INC %11110000
         +COPY_WITH_MASK_IMM_AND_INC %11110000
         +COPY_WITH_MASK_IMM         %11001100
@block3_aux
         dey
         +BRANCH_IF_Y_IS_OFFSCREEN @block2_aux
         +RESET_HGR_HI_AND_INC_BY 2
         +COPY_WITH_MASK_IMM_AND_INC %11110000
         +COPY_WITH_MASK_IMM_AND_INC %11110000
         +COPY_WITH_MASK_IMM_AND_INC %11110000
         +COPY_WITH_MASK_IMM         %11110000
@block2_aux
         dey
         +BRANCH_IF_Y_IS_OFFSCREEN @block1_aux
         +RESET_HGR_HI_AND_INC_BY 2
         +COPY_WITH_MASK_IMM_AND_INC %10110000
         +COPY_WITH_MASK_IMM_AND_INC %11000000
         +COPY_WITH_MASK_IMM_AND_INC %11000000
         +COPY_WITH_MASK_IMM         %10110000
@block1_aux
         dey
         +BRANCH_IF_Y_IS_OFFSCREEN @switchtomain
         +RESET_HGR_HI_AND_INC_BY 3
         +COPY_WITH_MASK_IMM_AND_INC %11000000
         +COPY_WITH_MASK_IMM         %11000000
@switchtomain
         sta   $C002
         sta   $C004
         iny
         dec   row
         +LBPL RowLoop
         lda   $c000
         bmi   @exit
         dec   col
         dec   counter
         +LBNE ColLoop
@exit    rts

; next table can not cross a page boundary
!if <* > $E8 {
         !align 255, 0
}
hgrrowlo
         !byte $00,$80,$00,$80,$00,$80,$00,$80
         !byte $28,$A8,$28,$A8,$28,$A8,$28,$A8
         !byte $50,$D0,$50,$D0,$50,$D0,$50,$D0

; next table can not cross a page boundary
!if <* > $E8 {
         !align 255, 0
}
hgrrowhi
         !byte $40,$40,$41,$41,$42,$42,$43,$43
         !byte $40,$40,$41,$41,$42,$42,$43,$43
         !byte $40,$40,$41,$41,$42,$42,$43,$43

!if * > $6700 {
         !error "Code too large, adjust COPY_TO_AUXMEM macro"
}