Table of Contents
Advertisement
Basic Disk Operating System (BDOS) Functions
Upon entry to function 6, register D L contains either (1) hexadecimal FF, denoting
a CONSOLE input status request,
(2)
hexadecimal FE, denoting a CONSOLE
status request, or (3) an ASCII character to be output to CONSOLE, where
CONSOLE is the logical console device.
• If the input value is FF, function· 6 directly calls the BIOS console input
function.
If
a character is ready, it is returned in AL; otherwise a zero is
returned in AL.
• If the input value is FE, function 6 returns zero in register AL ifno character
is ready, and FF in register AL otherwise.
• If the input value in DL is not FE or FF, function 6 sends the ASCII
character in DL to the console.
Do not use function 6 (with FE of FF) in combination with either function 1 or
function 2. Function 1 should be used in conjunction with function 2. Function 6
must be used independently.
GET I/O BYTE
ENTRY
RETURN
CL:
07H
FUNCTION 7
AL: I/O Byte Value
GET I/O BYTE
The Get I/O Byte function returns the current value of 10BYTE in register AL.
When the 10BYTE facility is implemented in the BIOS, IOBYTE contains the
current assignments for the logical devices CONSOLE, READER, PUNCH, and
LIST.
NOTE
CBIOS supports this call dynamically for the
LIST device only (see Chapter 5). However,
the call may be used in programs that operate
with standard CP/M calls to the BIOS.
4-7
Advertisement
Table of Contents
