Table of Contents
Advertisement
Fseek()
A l l o w s y o u t o m o v e t h e file p o i n t e r to c h a n g e t h e p o s i tio n in t h e file a t
w h i c h d a t a w ill b e r e a d o r w r i t t e n .
C macro format
l o n g p o s i t i o n , o f f s e t;
i n t h a n d l e , s e e k m o d e ;
p o s i t i o n =
F s e e k ( o f f s e t , h a n d l e , s e e k m o d e ) ;
Machine language format
m o v e . w
# s e e k m o d e , - ( s p )
m o v e . w
# h a n d l e , - ( s p )
# o f f s e t , - (s p )
m o v e .l
m o v e . w
# $ 4 2 , - ( s p )
#1
t r a p
a d d .l
# 1 0 , s p
Inputs
s e e k m o d e
w o r d
w o r d
h a n d l e
o f f s e t
l o n g
Results
DO
p o s i t i o n
l o n g
276
Fseek
Seek File
A f la g t h a t in d i c a t e s th e p o s i tio n r e la tiv e
to w h i c h th e file p o i n t e r w ill m o v e :
0 =
B e g i n n i n g o f file
1 =
C u r r e n t p o s i tio n
2 =
E n d o f file
T h e h a n d l e f o r th e file w h o s e p o i n t e r w ill
b e m o v e d .
T h e n u m b e r o f b y t e s to m o v e th e file
p o i n t e r . A p o s i tiv e n u m b e r m o v e s t o w a r d
t h e e n d o f t h e file , a n e g a t i v e n u m b e r
m o v e s t o w a r d th e b e g i n n i n g .
T h e a b s o l u t e c u r r e n t p o s i tio n o f t h e file p o i n t e r
a f t e r t h e F s e e k ( ) c a ll, e x p r e s s e d a s a n o f f s e t f r o m
th e s t a r t o f th e file .
Opcode = 66 ($42)
Hide quick links:
Advertisement
Table of Contents
