uxn/examples/screen.usm

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( screen )
:dev/r fff8 ( std read port )
:dev/w fff9 ( std write port )
;width 2 ;height 2
|0100 @RESET
( set read/write to dev/screen )
#01 DUP =dev/r =dev/w
( load screen size )
#00 IOR2 =width
#02 IOR2 =height
( draw pixel at screen center )
#0101
~width #0002 DIV2
~height #0002 DIV2
,putpixel JSR
BRK
|c000 @FRAME BRK
@putpixel
IOW2 ( y short )
IOW2 ( x short )
IOW ( color byte )
IOW ( redraw byte )
RTS
|d000 @ERROR BRK
|FFFA .RESET .FRAME .ERROR