Epson PX-8 User Manual page 124

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.
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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.
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