Write Cmos; Read Cmos - NEC CP/M-86 System Reference Manual

Advanced BIOS Functions
6-26
Write CMOS
ENTRY
CL: 08H
DS:DX: Data
Buffer Address
RETURN
EXT FUNC 8
WRITE CMOS
The Write CMOS function writes up to 512 bytes to CMOS RAM (battery back-up
memory). The data to be written is stored in an I/O buffer addressed by registers DS
and DX. The format of the buffer follows.
Address in CM OS
User buffer size
Offset of buffer
Base address of buffer
<------ 1 word
------>
Address in CMOS
=
Relative address in CMOS for data
Displacement from start of CMOS
Range is 0 - 511
User buffer size
=
Number of bytes to be written
Range is 1 - 512 bytes
Read CMOS
ENTRY
CL: 09H
DS:DX: Data
Buffer Address
RETURN
EXT FUNC 9 Data Buffer
READ CMOS
The Read CMOS function reads data in CMOS RAM (battery back-up memory)
into the buffer addressed by registers DS and DX. The system fills the data buffer in
the format defined in function 8, Write CMOS.