--------D-2101-------------------------------
INT 21 - DOS 1+ - READ CHARACTER FROM STANDARD INPUT, WITH ECHO
	AH = 01h
Return: AL = character read
Notes:	^C/^Break are checked, and INT 23 executed if read
	character is echoed to standard output
	standard input is always the keyboard and standard output the screen
	  under DOS 1.x, but they may be redirected under DOS 2+
SeeAlso: AH=06h,AH=07h,AH=08h,AH=0Ah
--------D-2106--DLFF-------------------------
INT 21 - DOS 1+ - DIRECT CONSOLE INPUT
	AH = 06h
	DL = FFh
Return: ZF set if no character available
	ZF clear if character available
	    AL = character read
Notes:	^C/^Break are NOT checked
	if the returned character is 00h, the user pressed a key with an
	  extended keycode, which will be returned by the next call of this
	  function
	reads from standard input, which is always the keyboard under DOS 1.x,
	  but may be redirected under DOS 2+
SeeAlso: AH=0Bh
--------D-2107-------------------------------
INT 21 - DOS 1+ - DIRECT CHARACTER INPUT, WITHOUT ECHO
	AH = 07h
Return: AL = character read from standard input
Notes:	does not check ^C/^Break
	standard input is always the keyboard under DOS 1.x, but may be
	  redirected under DOS 2+
	if the interim console flag is set (see AX=6301h), partially-formed
	  double-byte characters may be returned
SeeAlso: AH=01h,AH=06h,AH=08h,AH=0Ah
--------D-2108-------------------------------
INT 21 - DOS 1+ - CHARACTER INPUT WITHOUT ECHO
	AH = 08h
Return: AL = character read from standard input
Notes:	^C/^Break are checked, and INT 23 executed if detected
	standard input is always the keyboard under DOS 1.x, but may be
	  redirected under DOS 2+
	if the interim console flag is set (see AX=6301h), partially-formed
	  double-byte characters may be returned
SeeAlso: AH=01h,AH=06h,AH=07h,AH=0Ah,AH=64h
--------D-210A-------------------------------
INT 21 - DOS 1+ - BUFFERED INPUT
	AH = 0Ah
	DS:DX -> buffer (see below)
Return: buffer filled with user input
Notes:	^C/^Break are checked, and INT 23 is called if either detected
	reads from standard input, which may be redirected under DOS 2+
	if the maximum buffer size (see below) is set to 00h, this call returns
	  immediately without reading any input
SeeAlso: AH=0Ch,INT 2F/AX=4810h

Format of input buffer:
Offset	Size	Description
 00h	BYTE	maximum characters buffer can hold
 01h	BYTE	(input) number of chars from last input which may be recalled
		(return) number of characters actually read, excluding CR
 02h  N BYTEs	actual characters read, including the final carriage return
--------D-210B-------------------------------
INT 21 - DOS 1+ - GET STDIN STATUS
	AH = 0Bh
Return: AL = 00h if no character available
	   = FFh if character is available
Notes:	^C/^Break are checked, and INT 23 is called if either pressed
	standard input is always the keyboard under DOS 1.x, but may be
	  redirected under DOS 2+
	if the interim console flag is set (see AX=6301h), this function
	  returns AL=FFh if a partially-formed double-byte character is
	  available
SeeAlso: AH=06h"INPUT",AX=4406h
--------D-210C-------------------------------
INT 21 - DOS 1+ - FLUSH BUFFER AND READ STANDARD INPUT
	AH = 0Ch
	AL = STDIN input function to execute after flushing buffer
	other registers as appropriate for the input function
Return: as appropriate for the specified input function
Note:	if AL is not one of 01h,06h,07h,08h, or 0Ah, the buffer is flushed but
	  no input is attempted
SeeAlso: AH=01h,AH=06h"INPUT",AH=07h,AH=08h,AH=0Ah