collapseos/arch/z80/sms/blk/620

( kbd - implement (ps2kc) for SMS PS/2 adapter )
: (ps2kcA) ( for port A )
( Before reading a character, we must first verify that there
is something to read. When the adapter is finished filling its
'164 up, it resets the latch, which output's is connected to
TL. When the '164 is full, TL is low. Port A TL is bit 4 )
    _D1@ 0x10 AND IF 0 EXIT ( nothing ) THEN
    0 _THA! ( Port A TH output, low )
    _D1@ ( bit 3:0 go in 3:0 ) 0x0f AND ( n )
    1 _THA! ( Port A TH output, high )
    _D1@ ( bit 3:0 go in 7:4 ) 0x0f AND 4 LSHIFT OR ( n )
	2 _THA! ( TH input ) ;