Tandy 1000 Programmer's Reference Manual page 71

Chapter
1 I
System
Calls
RandomRead
Random Read Function Call 21H
Performs a random read of a record. The current block (offset
0CH) and current record (offset 20H) fields in the
FCB
are set to
agree with the relative record field (offset 21H). The record ad-
dressed by these fields is then loaded at the Disk Transfer
Address.
Entry Conditions:
AH
=
21H
DS:DX
=
pointer to the opened FCB of the file to read
Exit Conditions:
If AL
=
IfAL
=
If AL
=
If AL
=
Macro Definition:
r e a d - r a n m a c r o f c b
00H, the read was completed successfully.
01H, end of file was encountered; no data is in the
record.
02H, there was not enough room at the Disk Transfer
Address t o read 1 record; the read was canceled.
03H, end of file was encountered; a partial record was
read and padded to the record length with zeroes.
m Q V
d x , o f f s e t f c b
mov
a h , 2 1 H
I n t
21
H
endm
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