Atari ST series - Page 213

Iorec
Get I/O Buffer Record
Iorec() Opcode = 14
I o r e c () re tu rn s th e ad d re ss o f a d ata stru ctu re k n ow n as th e I/O bu ffer re 
c o rd , c on tain s in fo rm a tio n a b o u t th e in p u t bu ffer u sed b y a sp ecified d e 
v ice.
C macro format
in t d ev ;
lo n g b u frec;
b u frec = Io re c(d ev );
Machine language format
m o v e.w # d e v , - (sp )
m o v e .w # 1 4 , - ( s p )
trap # 1 4
ad d q .l # 4 ,s p
Inputs
d e v w o rd T h e in p ut d ev ic e w h ose bu ffer re co rd yo u
w ish to fin d:
0 = R S -232 serial p o rt
1 = C o n so le k ey bo ard
2 = M ID I p o rt
Results
DO b u frec lo n g T h e ad d re ss of th e d e v ice 's b uffer reco rd .
T his re co rd co n tain s 1 4 b y te s of d ata, in th e form at.
T h e co n te n ts of th e d ev ice 's bu ffer reco rd p o in te d to b y bufrec:
Byte Number Element Name Contents
0 - 3 ib uf A d d re ss o f th e in p u t bu ffer
4 - 5 ibu fsize Size of th e in p u t bu ffer (in b ytes)
6 - 7 ib ufh d In de x to h e ad (n ex t w rite p ositio n)
8 - 9 ibuftl In d ex to tail (n e x t rea d p ositio n)
1 0 -1 1 ibu flow Low water m a rk
1 2 -1 3 ib ufhi High water m ark
F or th e R S-232 d ev ice o n ly , an o u tp u t b u ffe r re co rd fo llow s im m ed iately
after th e in pu t bu ffer re co rd .
205