SETSEC
is
the entry point for the subroutine which sets the sector number
to
be read from
or
written to.
Entry parameter
Register BC
= Sector number
to
be accessed
(OOH
- 3FH)
If
a value other
than
OOH
to 3FH
is
specified, an error will occur when a read
or
write
is
performed.
Entry Point: WBOOT
+ 21H
SETDMA
is
the entry point for the subroutine which sets the starting address
of
the
128
byte DMA buffer area used for disk access.
Entry parameter
Register BC
= DMA address
'O:nn,
Entry Point: WBOOT + 24H
READ
is
the entry point for the subroutine which reads data from a disk drive
into the
DMA
buffer according to parameters set by the SELDSK, SETTRK,
SETSEC
and
SETDMA subroutines.
Return Parameter
Register A 0 Normal completion
Register A
= Other than 0 Abnormal completion
Entry Point: WBOOT
+ 27H
WRITE
is
the entry point for the subroutine which writes data to a disk drive
according to parameters set by the SELDSK, SETTRK, SETSEC and SETD-
MA
subroutines.
Entry parameter
Register C
OOH
Write standard format data.
Register C 01H Write unblocked data.
Register C 02H Write sequential file.
5-18
Return Parameter
Register A
=
OOH
Normal completion
Register A
= Other
than
OOH
Abnormal completion
Entry Point: WBOOT
+ 2DH
SECTRAN
is
the entry point for the subroutine which converts a logical sector
number into the corresponding physical sector number.
Entry parameters
Register BC
= Logical sector number
Register
HL
= Physical sector number
DISKTBL
AND
DISKROV - CHANGING DRIVES
The CONFIG program enables the logical and physical drives to be assigned
in three ways.
It
is
not
possible
to
have the Microcassette Drive assigned to any
drive other than drive
H:.
The logical
and
physical drives are assigned in a ta-
ble
of
7 bytes in length beginning
at
address
FID2H
(DISKTBL). The table
at
default contains the following data:
Address Logical Drive Code Physical Drive
FID2H
A:
00 RAM Disk
FID3H
B:
01
ROM Capsule 1
FID4H
C:
02
ROM Capsule 2
FID5H
D:
03
Floppy Disk Drive 1
FID6H
E:
04
Floppy Disk Drive 2
FID7H
F:
05
Floppy Disk Drive 3
FID8H
G:
06
Floppy Disk Drive 4
If
the code 07H
to
FFH
is
contained in this table, the drive cannot be selected.
If
the table
is
changed, the two bytes
at
address
FIDAH
(DISKROV) must also
be changed. This
is
the vector table which sets the
READ/WRITE
status
of
the drives.
If
the corresponding bit
is
"I"
the drive
is
set
to
RIO,
and
if
to
RIW
it
is
set
to
"0".
FIDAH
(DISKROV) includes the drive in the following
order.
bit
7 6 5 4 3 2 1 0
I
H:
I G: I
F:
I
E:
I D: I
c:
I B: I
A:
I
5-19
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