Register DE = Starting address
of
the memory area to which
data
is
trans-
ferred
Register BC
= Number
of
bytes
of
data
to
be transferred
Register A
= 0 -
Data
is
transferred
to
the user bank.
The operating system ROM cannot be changed
or
modified using this routine.
JUMPX
is
the entry point for the subroutine which jumps
to
the specified ad-
dress in the specified memory bank.
Entry Point: WBOOT
+ 63H
Entry parameters
Register IX
=
Jump
address
If
Address F539H (DISBNK) = - 1 System bank
If
Address F539H (DISBNK) = 0 User bank
NOTE:
When a stack is to be used at the destination address, a new stack must be estab-
lished.
IIMIE'
CALLX
is
the entry point for the subroutine which calls the specified address
in the specified bank.
Entry Point: WBOOT
+ 66H
Entry parameters
Register IX
= Call address
If
Address F539H (DISBNK) =
-1
- System
bank
If
Address F539H (DISBNK) = 0 - User bank
NOTE:
CALLX
uses one level in the user stack. Therefore, the stack pointer must be
used in the common area
in
RAM
(8000H to
OFFFFH),
and there must be at
least one free level
of
stack space.
5-32
1..1.1
SLAVE
is
the entry point for the subroutine which sends commands and
data
to the
6301
slave
CPU
and returns results and
data
from the slave. The use
of
this command
is
beyond the scope
of
this manual. Full details are shown
in the OS Reference Manual
and
Technical Reference Manual.
RDVRAM
is
the entry point for the subroutine which reads the contents
of
the virtual character screen.
Entry Point: WBOOT
+ 75H
Entry parameters
Register B Column at which the read
is
to
start
(1
to 80)
Register C
= Line at which the read
is
to start
(1
to virtual screen line
size)
Register DE
= Number
of
characters to be read
Register
HL
= Starting address
of
the area in which
data
read
is
to be
stored.
Return Parameters
Register A
OOH
- Normal completion
A 01H - Read error
A
FFH
- Parameter error
or
graphic screen read attempted
If
the end
of
the screen
is
encountered before the specified number
of
charac-
ters has been read, remaining addresses in the storage area are padded with spaces
and 1
is
returned in register A.
5.7.11 Miscellaneous Subroutines
Entry Point: WBOOT +
4EH
This
is
not supported.
It
will simply RETURN.
5-33
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