)
Call PCXDUMP screen-dump function with:
	INT xx
	AX = 1234h
	BX = dump type
	    0000h Color dump
	    0001h Immediate color dump
	    0002h Black/White dump
	    0003h Immediate B/W dump
	    0004h Inverted B/W dump
	    0005h Gray scaled dump
	    0006h Inverted gray scaled dump
	    0007h Text screen dump to text file
	    0008h Text screen dump to ansi file
Return: nothing
Notes:	if BX=0001h, 0003h, 0007h or 0008h the whole screen will be
	  dumped; the other valid values will draw a selection frame
	  on the screen except in text modes (text modes allow only
	  full screen dumps)
	this function doesn't perform the dump, it only requests it;
	  the dump will be performed after a few milliseconds if it's
	  safe to do so, thus the author recommends putting a 60 ms delay
	  after this call