41 lines
906 B
Forth
41 lines
906 B
Forth
# VGA Text Display
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~~~
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0xB8000 'VGA-BASE const
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#80 'COLUMNS const
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#25 'ROWS const
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'vga:Row var
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'vga:Column var
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:vga:position (-a)
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@vga:Row COLUMNS * #2 *
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@vga:Column #2 * +
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VGA-BASE + ;
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:cursor
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@vga:Row COLUMNS * @vga:Column + dup
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0x0F 0x3D4 pio:out-byte
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0xFF and 0x3D5 pio:out-byte
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0x0E 0x3D4 pio:out-byte
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#8 shift 0xFF and 0x3D5 pio:out-byte ;
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:scroll
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@vga:Row ROWS gt? [ #0 !vga:Row ] if cursor ;
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:vga:next
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&vga:Column v:inc
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@vga:Column COLUMNS gt? [ &vga:Row v:inc #0 !vga:Column ] if
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@vga:Row ROWS gt? [ #0 !vga:Row ] if cursor ;
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:putc (c-)
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#10 [ #0 !vga:Column &vga:Row v:inc scroll ] case
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#13 [ #0 !vga:Column &vga:Row v:inc scroll ] case
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vga:position ram:store-byte vga:next ;
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:clear (-)
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VGA-BASE COLUMNS ROWS * [ ASCII:SPACE over ram:store-byte #2 + ] times drop
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#0 !vga:Row #0 !vga:Column cursor ;
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:test &putc &c:put set-hook ;
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~~~
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