tvmx DEPRECATED

	tvmx(row.u1.r, column.u1.r, ibuf.sa.r, num_chars.i2.r)

	tvmx_c(row.i4.v, column.i4.v, ibuf.sa.r, num_chars.i4.v)

	This routine will perform I/O to the color TV. Character attributes
	(colors and blink) are specified for each  character  individually.
	ROW and COL are used to indicate the starting row and column  for
	reading or writing to the TV screen. 

	row	starting TV row for the transfer
	column	starting TV column for the transfer
	ibuf   	user buffer of ASCII data and character attributes  to  be
		read or written, one character per word.  The low byte  of
		each word contains an ASCII character and  the  high  byte
		contains the display attributes  for  the  character.  The
		ITVATT  function  is  available  to  build  the  character
		attribute.  Character attributes are described below.
	nchars  number of characters to be read from or written to the  TV
		screen.  If the  value  of  NCHARS  is  negative,  a  read
		operation is performed.  If NCHARS is  positive,  a  write
		operation  is   done.    Since   each  character  will  be
		accompanied by an attribute byte NCHARS  is  the number of
		16-bit words transferred.

	A CHARACTER ATTRIBUTE is defined as follows:

		bit 15   should be set to zero
		bit 14   BLINK character if logical 1
		bit 13	 RED background
		bit 12	 GREEN background
		bit 11	 BLUE background
		bit 10	 RED foreground
		bit  9	 GREEN foreground
		bit  8	 BLUE foreground

	This function requires the following include files:

	clib_h

	Related functions:

	window_tvmx(_c), btvmx(_c)