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borielboriel
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Add back old scroll routines as Scroll...Aligned.
These are slightly faster and smaller, but operates aligned to columns.
1 parent 1c70ae1 commit 3079647

3 files changed

Lines changed: 868 additions & 2 deletions

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‎src/lib/arch/zx48k/stdlib/scroll.bas‎

Lines changed: 316 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -717,6 +717,322 @@ EMPTYLINE:
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end asm
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end sub
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' ----------------------------------------------------------------
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' sub ScrollRightAligned
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' pixel by pixel right scroll.
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' scrolls 1 pixel right the window defined by (x1, y1, x2, y2)
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' This scroll is aligned to columns.
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' x1 and x2 are divided by 8 and rounded down (floor) to get the column number (0..31)
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' ----------------------------------------------------------------
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sub fastcall ScrollRightAligned(x1 as uByte, y1 as uByte, x2 as Ubyte, y2 as Ubyte)
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asm
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push namespace core
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PROC
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LOCAL LOOP1
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LOCAL LOOP2
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; a = x1
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pop hl ; RET address
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pop bc ; b = y1
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pop de ; d = x2
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ex (sp), hl ; h = y2, (sp) = RET address. Stack ok now
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ld c, a ; BC = y1x1
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ld a, d
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sub c
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ret c ; x1 > x2
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srl a
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srl a
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srl a
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inc a
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ld e, a ; e = (x2 - x1) / 8 + 1
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ld a, h
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sub b
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ret c ; y1 > y2
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inc a
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ld d, a ; d = y2 - y1 + 1
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ld b, h ; BC = y2x1
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ld a, 191
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LOCAL __PIXEL_ADDR
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__PIXEL_ADDR EQU 22ACh
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call __PIXEL_ADDR
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res 6, h ; Starts from 0
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ld bc, (SCREEN_ADDR)
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add hl, bc ; Now current offset
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LOOP1:
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push hl
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ld b, e ; C cols
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or a ; clear carry flag
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LOOP2:
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rr (hl)
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inc hl
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djnz LOOP2
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pop hl
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dec d
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ret z
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call SP.PixelDown
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jp LOOP1
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ENDP
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pop namespace
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end asm
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end sub
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' ----------------------------------------------------------------
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' sub ScrolLeftAligned
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' pixel by pixel left scroll
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' scrolls 1 pixel left the window defined by (x1, y1, x2, y2)
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' This scroll is aligned to columns.
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' x1 and x2 are divided by 8 and rounded down (floor) to get the column number (0..31)
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' ----------------------------------------------------------------
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sub fastcall ScrollLeftAligned(x1 as uByte, y1 as uByte, x2 as Ubyte, y2 as Ubyte)
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asm
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push namespace core
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PROC
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LOCAL LOOP1
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LOCAL LOOP2
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; a = x1
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pop hl ; RET address
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pop bc ; b = y1
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pop de ; d = x2
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ex (sp), hl ; h = y2, (sp) = RET address. Stack ok now
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ld c, a ; BC = y1x1
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ld a, d
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sub c
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ret c ; x1 > x2
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srl a
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srl a
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srl a
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inc a
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ld e, a ; e = (x2 - x1) / 8 + 1
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ld a, h
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sub b
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ret c ; y1 > y2
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ld c, d
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inc a
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ld d, a ; d = y2 - y1 + 1
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ld b, h ; BC = y2x1
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ld a, 191
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LOCAL __PIXEL_ADDR
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__PIXEL_ADDR EQU 22ACh
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call __PIXEL_ADDR
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res 6, h ; Starts from 0
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ld bc, (SCREEN_ADDR)
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add hl, bc ; Now current offset
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LOOP1:
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push hl
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ld b, e ; C cols
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or a ; clear carry flag
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LOOP2:
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rl (hl)
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dec hl
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djnz LOOP2
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pop hl
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dec d
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ret z
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call SP.PixelDown
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jp LOOP1
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ENDP
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pop namespace
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end asm
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end sub
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' ----------------------------------------------------------------
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' sub ScrolUpAligned
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' pixel by pixel up scroll
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' scrolls 1 pixel up the window defined by (x1, y1, x2, y2)
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' This scroll is aligned to columns.
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' x1 and x2 are divided by 8 and rounded down (floor) to get the column number (0..31)
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' ----------------------------------------------------------------
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sub fastcall ScrollUpAligned(x1 as uByte, y1 as uByte, x2 as Ubyte, y2 as Ubyte)
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asm
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push namespace core
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PROC
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LOCAL LOOP1
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; a = x1
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pop hl ; RET address
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pop bc ; b = y1
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pop de ; d = x2
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ex (sp), hl ; h = y2, (sp) = RET address. Stack ok now
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ld c, a ; BC = y1x1
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ld a, d
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sub c
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ret c ; x1 > x2
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srl a
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srl a
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srl a
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inc a
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ld e, a ; e = (x2 - x1) / 8 + 1
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ex af, af' ; save it for later
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ld a, h
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sub b
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ret c ; y1 > y2
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inc a
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ld d, a ; d = y2 - y1 + 1
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ld b, h ; BC = y2x1
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ld a, 191
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LOCAL __PIXEL_ADDR
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__PIXEL_ADDR EQU 22ACh
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call __PIXEL_ADDR
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res 6, h ; Starts from 0
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ld bc, (SCREEN_ADDR)
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add hl, bc ; Now current offset
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ld a, d ; Num. of scan lines
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ld b, 0
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exx
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ld b, a ; Scan lines counter
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ex af, af' ; Recovers cols
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ld c, a
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jp LOOP_START
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LOOP1:
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exx
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ld d, h
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ld e, l
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ld c, a ; C cols
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call SP.PixelDown
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push hl
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ldir
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pop hl
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exx
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ld a, c ; Recovers C Cols
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LOCAL LOOP_START
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LOOP_START:
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djnz LOOP1
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; Clears bottom line
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exx
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ld (hl), 0
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ld d, h
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ld e, l
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inc de
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ld c, a
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dec c
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ret z
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ldir
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ENDP
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pop namespace
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end asm
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end sub
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' ----------------------------------------------------------------
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' sub ScrolDownAligned
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' pixel by pixel down scroll
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' scrolls 1 pixel down the window defined by (x1, y1, x2, y2)
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' This scroll is aligned to columns.
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' x1 and x2 are divided by 8 and rounded down (floor) to get the column number (0..31)
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' ----------------------------------------------------------------
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sub fastcall ScrollDownAligned(x1 as uByte, y1 as uByte, x2 as Ubyte, y2 as Ubyte)
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asm
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push namespace core
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PROC
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LOCAL LOOP1
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; a = x1
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pop hl ; RET address
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pop bc ; b = y1
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pop de ; d = x2
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ex (sp), hl ; h = y2, (sp) = RET address. Stack ok now
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ld c, a ; BC = y1x1
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ld a, d
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sub c
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ret c ; x1 > x2
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srl a
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srl a
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srl a
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inc a
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ld e, a ; e = (x2 - x1) / 8 + 1
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ex af, af' ; save it for later
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ld a, h
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sub b
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ret c ; y1 > y2
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inc a
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ld d, a ; d = y2 - y1 + 1
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ld a, 191
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LOCAL __PIXEL_ADDR
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__PIXEL_ADDR EQU 22ACh
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call __PIXEL_ADDR
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res 6, h ; Starts from 0
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ld bc, (SCREEN_ADDR)
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add hl, bc ; Now current offset
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ld a, d ; Num. of scan lines
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ld b, 0
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exx
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ld b, a ; Scan lines counter
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ex af, af' ; Recovers cols
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ld c, a
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jp LOOP_START
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LOOP1:
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exx
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ld d, h
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ld e, l
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ld c, a ; C cols
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call SP.PixelUp
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push hl
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ldir
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pop hl
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exx
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ld a, c ; Recovers C Cols
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LOCAL LOOP_START
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LOOP_START:
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djnz LOOP1
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; Clears top line
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exx
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ld (hl), 0
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ld d, h
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ld e, l
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inc de
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ld c, a
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dec c
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ret z
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ldir
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ENDP
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pop namespace
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end asm
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end sub
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#pragma pop(case_insensitive)
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7221038
REM the following is required, because it defines SCREEN_ADDR and SCREEN_ATTR_ADDR

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