INT 16h,  01h (1)        Keyboard Status                                  all

Checks to see if a character is available in the buffer.

On entry:      AH         01h

Returns:       Zero       0, if character is available
1, if character is not available
AL         ASCII character code (if character is
available)
AH         Scan code (if character is available)

                                                                          

Notes:         If a character is available, the Zero Flag is
cleared and AX contains the ASCII value in AL and
the scan code in AH. The character is not removed
from the buffer. Use Service 00h to remove the
character from the buffer. See Service 00h for a
complete description of the meaning of AX if a
character is available.

This service is excellent for clearing the keyboard
or allowing a program to be interruptable by a
specific key sequence.

See Service 11h for an equivalent service that
supports the enhanced (101/102-key) keyboard.

See also: INT 16h, 00h
See also: INT 16h, 11h
See also: Scan Codes

INT 16h, 01h (1) Keyboard Status all