Bitwise routine include files by Jon Martin.
Included files:
readme.txt - this readme
bitwise.inc - include file with routines for bitshifting 2-byte registers. 
for example: the equivalent of srl hl would be call SRLHL
also included in the file are routines for sll, the undocumented command.
boolean.inc - include file with routines for booleans with 2-byte registers.
operation booleans hl with one of the other 2 16-bit registers.
for example: the equivalent of xor de would be call XORDE.
doublesprite.inc - include file with my self-made 16-bit xor sprite routine.  This
is a routine to write a sprite to plotsscreen/graph_mem/gbuf(or whatever you call it).
doublemaskedsprite.inc - include file with doublewide masked sprite routine.  This routine
ANDs a mask to plotsscreen, and then ORs the sprite on top.  Useful if you want to retain the background.
sprites should be in the following format:
sixteenbitsprite:	;or whatever you want to call it
	.db %xxxxxxxx,%xxxxxxxx		;4-row sprite
	.db %xxxxxxxx,%xxxxxxxx
	.db %xxxxxxxx,%xxxxxxxx
	.db %xxxxxxxx,%xxxxxxxx
Inputs for sprite routine:
a=column
e=row
b=height (number of rows)
ix=sprite pointer
iy=sprite mask (if using masked sprite routine)