Atari ST series Technical Reference Manual page 262

Get RS-232 Input Status
Cauxis()
T h is f u n c t i o n a l l o w s y o u t o d e t e r m i n e w h e t h e r t h e r e is a c h a r a c t e r w a i t i n g
to b e r e c e i v e d f r o m t h e R S - 2 3 2 s e r i a l d e v i c e .
C macro format
i n t s t a t u s ;
s t a t u s = C a u x i s ( );
Machine language format
m o v e . w # $ 1 2 , - ( s p )
t r a p # 1
a d d q .l # 2 , s p
Inputs
N o n e
Results
DO s t a t u s l o n g
See also
C a u x i n ( )
254
Cauxis
A v a l u e o f 0 m e a n s t h e r e a r e n o c h a r a c t e r s w a i t i n g ,
w h ile - 1 m e a n s a t l e a s t o n e c h a r a c t e r is w a i t i n g to
b e r e c e i v e d .
Opcode = 18 ($12)