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SDFI, SDFO–System Data Format I/O Routines
The SDFINT$ entry point does not truncate images that overflow the image buffer but
instead returns an error. The recommended image buffer word length is returned in
register A5. To read the entire image, the calling program must place the address and
word length of a larger image buffer in the packet and call SDFINT$ again. If a
continuation record (051 in S1 of the ICW) causes an overflow, the image buffer will
contain the part just read, and word 10 of the FCT will contain an ICW for the portion of
the image returned in the image buffer. To continue reading the image, the calling
program must call SDFINT$ again. SDFI will return the next portion of the image.
SDFI processes continuation records (051 in S1 of the ICW) and does not return them to
the calling program, unless the image being continued is a type 061 special print control
record. Since the type 061 record may exceed 63 words in length, the special print
control record will be returned, and each continuation record associated with that special
print control record will be returned as a separate record. All other control records are
returned to the calling program.
Calling Sequence for SDFI$
Auto Switch Common Bank or Relocatable Relocatable
L,U A0,address-of-packet
LMJ X11,CBSDFI$-1
error return
end-of-file return
normal return
Calling Sequence for SDFINT$
L,U A0,address-of-packet
I$BJ X11,CBSDFI$
error return
end-of-file return
normal return
L,U A0,address-of-packet
LMJ X11,SDFI$
error return
end-of-file return
normal return
Auto Switch Common Bank or Relocatable Relocatable
L,U A0,address-of-packet
LMJ X11,CBSDFINT$-1
error return
end-of-file return
normal return
L,U A0,address-of-packet
I$BJ X11,CBSDFINT$
error return
end-of-file return
normal return
L,U A0,address-of-packet
LMJ X11,SDFINT$
error return
end-of-file return
normal return
Returns
If SDFI takes the error return, register A4 contains the error code. See 21.3 for an
explanation of error codes.
If SDFI takes the end-of-file return, an end-of-file control record was encountered (077 in
S1 of the ICW). If the file or element read by SDFI does not contain an EOF control
record, SDFI does not terminate correctly.
If SDFI takes the normal return, the image has been read and is returned in the image
buffer.
7833 1733–004 21–9