e VIC 20 Kernel ROM function to clear the screen
inputs: none
outputs: none
</pre></td></tr><tr><td id="print_a">print_a</td><td><pre>use VIC 20 Kernel ROM function to print a character to the screen
inputs: A contains petscii value of character to print
outputs: none
</pre></td></tr><tr><td id="print_a_inverse">print_a_inverse</td><td><pre>print a single char in inverse text:
</pre></td></tr><tr><td id="print_cr">print_cr</td><td><pre>use VIC 20 Kernel ROM function to move to a new line
inputs: none
