collapseos/blk/587

: (key)
    ( inc then fetch )
    [ ACIAR> LITN ] C@ 1+ [ ACIA_BUFSZ 1- LITN ] AND
    ( As long as R> == W>-1, it means that buffer is empty )
    BEGIN DUP [ ACIAW> LITN ] C@ = NOT UNTIL
    DUP [ ACIA( LITN ] @ + C@ ( ridx c )
    SWAP [ ACIAR> LITN ] C! ( c )
;
: (emit)
    ( As long at CTL bit 1 is low, we are transmitting. wait )
    BEGIN [ ACIA_CTL LITN ] PC@ 0x02 AND UNTIL
    ( The way is clear, go! )
    [ ACIA_IO LITN ] PC!
;
acia: make wholly cross compilable 2020-05-12 11:52:44 +10:00			`: (key)`
			`( inc then fetch )`
acia: simplify driver The previous approach of maintaining R> and W> pointers was conceptually simple, but made INT handler code actually quite complex. Now, we maintain indexes instead. It's much easier to perform bounds checks and to compare for equality, something we have to do quick in the INT handler. 2020-08-15 12:51:27 +10:00			`[ ACIAR> LITN ] C@ 1+ [ ACIA_BUFSZ 1- LITN ] AND`
acia: make wholly cross compilable 2020-05-12 11:52:44 +10:00			`( As long as R> == W>-1, it means that buffer is empty )`
acia: simplify driver The previous approach of maintaining R> and W> pointers was conceptually simple, but made INT handler code actually quite complex. Now, we maintain indexes instead. It's much easier to perform bounds checks and to compare for equality, something we have to do quick in the INT handler. 2020-08-15 12:51:27 +10:00			`BEGIN DUP [ ACIAW> LITN ] C@ = NOT UNTIL`
			`DUP [ ACIA( LITN ] @ + C@ ( ridx c )`
			`SWAP [ ACIAR> LITN ] C! ( c )`
acia: make wholly cross compilable 2020-05-12 11:52:44 +10:00			`;`
			`: (emit)`
			`( As long at CTL bit 1 is low, we are transmitting. wait )`
			`BEGIN [ ACIA_CTL LITN ] PC@ 0x02 AND UNTIL`
			`( The way is clear, go! )`
			`[ ACIA_IO LITN ] PC!`
			`;`