Stupid(?) vector trick

[Whammo]

If we turn off IRQ's and redirect the NMI vector to the IRQ routine,
durexForth will only read the keyboard when the RESTORE key is pressed.
Hold down the key and press RESTORE.

: irqpeek $dc0e c@ ;
: irqpoke $dc0e c! ;
: irqoff irqpeek $fe and irqpoke ;
: irqon irqpeek 1 or irqpoke ;

: nmisub ( addr -- )
irqoff $318 ! ; \ nmi vector

: fix [ cli, ] irqon ;
 
$ff48 nmisub