. . . sort of.
See
http://www.falvotech.com/tmp/screenshot.png for the current screenshot of the K2 emulator running.
I should point out that there is no actual Forth software running in ROM just yet -- I needed some text to print to the screen for testing purposes, and couldn't think of anything more impressive than the boot-up banner itself.
Code to print a single line of text is as follows:
Code:
.proc DrawMeSomeText
;
; Set the string pointer into the input pseudo-register #0
;
lda #msg
sta I0
stz I0+2
;
; Set string length here
;
lda #msgLength
sta I1
;
; Set drawing coordinates
;
stz leftEdge
lda #5*80 ; 80 bytes per scanline
sta topEdge
;
; Reset the font bitmap pointer, and render!
;
jsr DisplayUseSystemFont
jmp DisplayXorText
.endproc
.rodata
msg:
.byte "Look ma, this is subscript!!"
msgLength = *-msg
Note that a string's horizontal coordinate is expressed in terms of characters, since this is easiest for the 65816 to handle. The vertical component, however, is expressed in
pixels, since the hardware is fully capable of supporting it (as there is no text mode, it can draw text on any scanline in the framebuffer's bitmap).
As you can see from the screenshot, rendering double-height characters is easy too. Instead of calling DisplayXorText, just invoke DisplayXorTextDouble. Everything else is the same.
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