bytes to planes conversions in 8 or 4 planes (in both ways)
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	The basic routine was given to me by Douglas Little who had it from programmers working on the Amiga, so I don't know the creator of it. Douglas knew that this routine could speed up M_PLAYER in TT mode.
	Then I adapted the code to suit my needs, in particular for the 4 planes (16 colors) mode used by MP_STE.

	Each routine comes with three parameters:
	LONG size : size in pixels (multiple of 16 pixels).
	char *src: pointer to the source data (even)
	char *dest: pointeur to the area to be filled (even)

	You can set scr=dest to get the result in the same buffer.

	bytes_to_planes8(LONG size, char *src, char *dest);
	-> bytes to 8 planes (256 colors)
	hbytes_to_planes4(LONG size, char *src, char *dest);
	-> bytes (00, 10, 20, ... F0) to 4 planes, the source is in the high nibble of the byte
	hbytes_to_planesx4(LONG size, char *src, char *dest);
	-> bytes (0x, 1x, 2x, ... Fx) to 4 planes, the source is in the high nibble of the byte, extra bits cleared.
	bytes_to_planes4(LONG size, char *src, char *dest);
	-> bytes (00,01,02,..,0F) to 4 planes, the source is in the low nibble of the byte
	bytes_to_planesx4(LONG size, char *src, char *dest);
	-> bytes (x0,x1,x2,..,xF) to 4 planes, the source is in the low nibble of the byte, extra bits cleared.
	planes_to_bytes8(LONG size, char *src, char *dest);
	-> 8 planes to bytes
	planes_to_bytes4(LONG size, char *src, char *dest);
	-> 4 planes to bytes (0,1,2,..,F)

	For the 16 colors mode, I started with hbytes_to_planes4 because my routine output grey levels from 00 to FF and, taking the high nibble gave me values from 0 to F corresponding to 16 grey levels. I added the routine bytes_to_planes4 for those who have directly bytes from 0 to F as a source.

	CHUNKY.S is to be used with ASSEMBLE (brainstorm)
	CHUNKYPC.S is to be used byt any other assembler (such as Pure C)

	Guillaume Tello.
