Atari ST series - Page 281

Fread
Read File
Fread() Opcode = 63 ($3F)
T his fu nctio n r e ad s a spe cified n u m b er of b ytes from a n o p en file.
C macro format
lo n g sta tu s, co u n t;
in t h an d le ;
ch a r ^bu ffer;
statu s = F rea d (h a n d le, co u n t, bu ffer);
Machine language format
m o v e.l b uffer, - (sp )
m ov e.l
# c o u n t , - (sp ) i
m ov e.l # h a n d l e , - (sp )
m o v e .w # $ 3 F , - (sp )
trap
# 1
ad d .l
# 1 2 ,sp
Inputs
bu ffer
lo ng A p o in te r to th e bu ffer w h ere th e d ata
th at is rea d in w ill be sto re d .
co u n t
lo n g
T h e n u m b er o f b yte s to re a d . N o te: T h is
m u st be a lo n g valu e.
h an d le w o rd
T h e file ha n d le of th e file to re ad .
Results
DO statu s w o rd If th e fun ctio n su c ce ed s, th e actu a l n u m b er o f b y tes
re ad is retu rn ed . If th e fu n ction a ttem p ts to rea d
p ast th e e n d of th e file, 0 is re tu rn e d . F o r an y o th er
e rro r, a ne g ativ e G EM D O S erro r n u m b er is re tu rn e d
See also
F o p e n ( ), F c lo s e ()
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