BZ Compressor V1.2, SX/GX
		^^^^^^^^^^^^^^^^^^^^^^^^^

	(C) Mika Heiskanen, mheiskan@delta.hut.fi

	Stack:	( ob --> $bz  |  $bz --> ob )
	Keys:	ON-key aborts compression.
	Memory:
		Fast compression requires using buffering to find matches
		fast. Two different BZ versions are provided for the user to
		select from based on the configuration of his calculator. For
		more details see the 'Programs' section below.
		Decompression requires no extra memory.

	Algorithm:
		LZ77 class compressor with bit-level codes for matches and
		literal lenght fields. Literals themselves are stored as is
		at the end of output for decompression speed.
		Matches are found by separate chaining in a ring buffer.
		More details in the source code. Note that several of the
		variables are assembly time only, eg you may not be able to
		decompress with another BZ program if you change the values.

		Programs
		^^^^^^^^

		BZ4 uses a hash buffer of size #400 and thus requires
		11264 bytes of memory for the internal buffers. Intended
		for HP48 GX and other versions when 128K RAM is available.

		BZ1 uses a hash buffer of size #100 and thus requires
		7424 bytes of memory for the internal buffers. Intended
		for HP48 S/SX/GX when in 32K RAM configuration.

		For the effects of hash buffer size on speed see bz.s. If you
		desire to use another buffer size then just modify HSHSIZE
		to one of the listed values, change the BZ version message
		accordingly and compile the source. HSHSIZE only effects
		compression speed, not the efficiency.

		UBZ is the extracted uncompressor code which can be freely
		used in non-commercial programs.


		Compression Efficiency Comparison Tables
		^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

	All measurements were done on a GX with ~75K of free memory.

	Most of the compressors can be found from

		seq.uncwil.edu:/hp48/Uploads.Dec/compress/

	GZ and PK compressors are replaced by the new BZ compressor.


	Input:	GZ.S	13444 bytes	( SRPL/ML source code )

		Size	%CH	CTime	UTime

	BZ	6205	-53.85	 18.00	1.45
	GZ 1.2	6637.5	-50.63	 13.48	0.45
	PK 15	6741	-49.86	 46.62	0.92	(w/ upk)
	PK 0	6771	-49.64	 25.27	0.92	(w/ upk)
	LZ8B	8079	-39.91	 39.11	1.40	(lzss library w/ unpk)
	LZ10	8115	-39.64	213.75	2.64	(lzss library w/ unpk)
	CMPR	8795.5	-34.58	 98.27	1.89	(compress.lib w/ dcmpr)
	RFPG	8796	-34.57	 82.72	1.92	(w/ rfug)

	Next input produced by:
	<< ERASE 'PPAR' PURGE 'SIN(X)' STEQ DRAW DRAX PICT RCL >>

	Input:	grob	1098 bytes

		Size	%CH	CTime	UTime

	BZ	241.5	-78.01	 5.49	0.08
	GZ 1.2	265.5	-75.82	 4.56	0.03
	PK 15	268	-75.69	 5.40	0.08	(w/ upk)
	CMPR	285	-74.04	 5.23	0.14	(compress.lib w/ dcmpr)
	RFPG	286	-73.95	 2.34	0.17	(w/ rfug)
	PK 0	293.5	-73.27	 1.94	0.08	(w/ upk)
	LZ8B	299	-72.77	 5.88	0.08	(lzss library w/ unpk)
	LZ10	356.5	-67.53	 5.98	0.21	(lzss library w/ unpk)
	PGROB	383	-65.12	 0.19	fail	(w/ upgrob)


	Input:	BZ	1506 bytes	(BZ compressor binary)

		Size	%CH	CTime	UTime

	BZ	1352	-10.23	 2.22	0.14
	LZ10	1352.5	-10.19	49.05	0.29	(lzss library w/ unpk)
	PK 15	1378	 -8.50	 3.64	0.04	(w/ upk)
	PK 0	1378	 -8.50	 3.61	0.04	(w/ upk)
	GZ 1.2	1380.5	 -8.33	 1.68	0.05
	CMPR	1384.5	 -8.07	19.05	0.17	(compress.lib w/ dcmpr)
	RFPG	1385	 -8.03	14.47	0.21	(w/ rfug)
	LZ8B	-	  0	 7.44	-	(lzss library w/ unpk)


	Input:	Lem.lib	11412.5 bytes	("Library 1213:  Lemmings .. V1.2")

		Size	%CH	CTime	UTime

	BZ	10153.5	-11.03	 22.70	0.82
	PK 15	10219.5	-10.45	113.69	0.31	(w/ upk)
	PK 0	10226	-10.40	 30.34	0.31	(w/ upk)
	GZ 1.2	10281.5	 -9.91	 12.60	0.28
	LZ10	10361.5	 -9.21	401.98	2.06	(lzss library w/ unpk)
	CMPR	10394.5	 -8.92	137.23	0.96	(compress.lib w/ dcmpr)
	RFPG	10395	 -8.92	118.00	1.26	(w/ rfug)
	LZ8B	11103	 -2.71	 55.68	0.80	(lzss library w/ unpk)