This function attempts to read a character from the keyboard input buffer. Each character is stored in the buffer as a two-byte pair consisting of the scancode and its ASCII equivalent. If a scancode/ASCII pair is available, it is removed from the buffer and returned in AX. Note that this function discards certain keycodes (see "I16Clip" on page 3-113). Use function 10h for the extended scancodes. The function waits until a scancode/ASCII pair is present in the keyboard input buffer. Except for hardware interrupts, no other processing occurs until a key is pressed on the keyboard.