81/03/30	ins.c: fix exg op code
81/03/18	ins.c: fix subxb, subxw, subxl op codes
81/03/13	init.c: permit foo or foo.a68 as source file
81/03/13	ins.c:  fix roxrl op code
81/03/04	mical.h, ps.c, scan.c, sym.c: added local symbols
81/03/03	mical.h, inst.h, init.c, ins.c, scan.c, ps.c:
		  add ~ operator and .ascii, .asciz pseudo ops
81/03/02	mical.h, scan.c: add * operator in term()
81/02/25	scan.c: add 0x syntax for hex constants in term()
81/02/24	scan.c: fix .=.+n bug in sassign()