Category: <b>runtime support</b>
<p>
<pre><b>INT 64 - Extended Batch Language v3.14+</b>

	AH = function
	    00h to 5Fh chained to previous handler
	    60h to 6Ch reserved, return immediately
	    80h to FFh chained to previous handler
	    6Dh (v4.01+) insert tone in queue
		AL = ???
		CX = frequency in Hertz
		DL = duration in clock ticks
		Return: AL = 00h if note stored
			   = 01h if no room to store
	    6Eh clear ??? counter/flag
	    6Fh return counter/flag that AH=6Eh clears
	    70h ???
		AL = ???
	    71h ???
		AL = ???
	    72h ???
	    73h insert byte at end of keyboard buffer
		AL = byte to insert
		Return: AL = 00h if byte inserted
			   = 01h if no room to store
	    74h insert byte at front of keyboard buffer
		AL = byte to insert
		Return: AL = 00h if byte inserted
			   = 01h if no room to store
	    75h ???
	    76h get keyboard "stack" status
		AL = 'K' if kbd read will read physical keyboard
		     'S' if it will read EBL internal keyboard buffer
		AH = ???
	    77h clear internal keyboard buffer
	    78h ???
		AL = ???
	    79h ???
	    7Ah ???
		AL = ???
	    7Bh ???
		AL = ???
	    7Ch ???
		AL = ???
	    7Dh ???
		AL = ???
	    7Eh clear buffer for ???
	    7Fh installation check
		Return: CX = version in BCD
			DI = segment of ???
			BX = segment of next program's PSP???
Program: Extended Batch Language is a batch-file enhancer by Seaware
Notes:	the chaining does not check whether the interrupt had been hooked
	  before, so if you try to chain when the previous vector was
	  0000h:0000h, you'll be in trouble
	functions 72h and 7Ah-7Dh appear to be interfaces to the optional
	  floating-point and extended function packages
Index:	installation check;EBL|installation check;Extended Batch Language
</pre>