*20
/D4RULES
	 
/INSTRUCTIONS FOR DBLFLT4
	 
/DBLFLT4 IS A CUTDOWN VERSION OF DBLFLT3
/ WHICH WILL FIT IN ONE MEMORY SEGMENT.
/SEVERAL DBLFLT3 ROUTINES HAVE BEEN DELETED
/ AND OTHERS HAVE BEEN CHANGED.
	 
/THIS DOCUMENT PRESUMES A PRIOR KNOWLEDGE OF
/ THE DBLFLT3 DOCUMENT (DECUS 12-7).
/DESCRIBED HERE ARE THE DIFFERENCES BETWEEN
/ DBLFLT3 AND DBLFLT4.
	 
/BY D.A. OVERTON
/6-6-71
	 
/UTILIZATION OF THE FOLLOWING SUBROUTINES
/ IS UNCHANGED IN DBLFLT4:
/	ADDT
/	SUBT
/	MULT
/	DIVIDE
/	TRANS
/	FIX
/	FIX12
/	FLOAT
/	FLOT12
/	COMPAR
/	SIGN
/	MAGTST
/	LOG10
/	LOGN
/	LOG2
/	EXPON
	 
/THE FOLLOWING FUNCTIONS HAVE BEEN DELETED
/ FROM DBLFLT4:
/	TYP8
/	TYP6
/	KBDI
/	KBD
/	LFCR
/	TTYIN
/	TTYOUT
/	TEN2N
/	IRLOAD
/	ABS1
/	COM1
/	SINDEG
/	COSDEG
/	SINRAD
/	COSRAD
/	SINP12
/	COSP12
/	ARCSIN
/	ARCTAN
/	NEGFAC
	 
	 
/THE FOLLOWING ROUTINES HAVE BEEN ADDED
/ OR CHANGED:
	 
/SQROOT
/	THE SQUARE ROOT FUNCTION HAS BEEN
/	  SPEEDED UP AND NOW AVERAGES
/	  ABOUT 55 MSEC.
/	THE CALLING SEQUENCE FOR USING
/	  SQROOT HAS NOT CHANGED.
/	THE SUBROUTINE NOW USES TEM1.
	 
/POWSER
/	THE CALLING SEQUENCE FOR THE POWER
/	  SERIES SUBROUTINE IS CHANGED.
/	TO USE THIS ROUTINE, PLACE X IN TEM2,
/	  AND (1-NO. OF TERMS) IN THE
/	  ACCUMULATOR.
/	SET THE DATA FIELD TO THE TABLE 
/	 OF CONSTANTS.
/	ENTER VIA: JMP POWSER
/	THE LOCATION FOLLOWING THIS ENTRY
/	  JUMP MUST CONTAIN THE DATA
/	  FIELD ADDRESS OF THE EXPONENT
/	  OF THE FIRST CONSTANT IN THE
/	  POWER SERIES, EXPRESSED AS A
/	  NEGATIVE (ONES COMPLEMENT) ARGUMENT.
/	RETURN IS AT .+2
/	  WITH THE RESULT LEFT IN THE FAC.
	 
/ABSVAL
/	THIS IS A NEW SUBROUTINE WHICH
/	  WILL TAKE THE ABSOLUTE VALUE
/	  OF A DBLFLT NUMBER.
/	ENTER VIA: JMP ABSVAL
/	THE ENTRY JMP IS FOLLOWED BY A
/	  SINGLE (NEGATIVE) ARGUMENT
/	  WHICH SPECIFIES THE LOCATION
/	  OF THE NUMBER TO BE ACTED ON.
/	THE RESULTING ABSOLUTE VALUE IS
/	  LEFT IN THE SAME LOCATION
/	  WHERE THE NUMBER WAS FOUND.
/	RETURN IS AT .+2
	 
/NEGATE
/	THIS IS A NEW SUBROUTINE WHICH
/	  COMPLEMENTS THE DBLFLT NUMBER
/	 SPECIFIED BY THE ARGUMENT.
/	ENTER VIA: JMP NEGATE
/	A SINGLE (NEGATIVE) ARGUMENT
/	  FOLLOWS THE ENTRY JMP.
/	RETURN IS AT .+2
	 
	 
/CONSTANTS AND MEMORY STORAGE LOCATIONS:
/	THE ABSOLUTE LOCATION OF MOST
/	  DBLFLT FORMAT CONSTANTS
/	  AND USER PROGRAM STORAGE LOCATIONS
/	  IS CHANGED IN DBLFLT4.
/	THESE ARE DEFINED IN THE PROGRAM DBL4GO
/	13 DBLFLT STORAGE REGISTERS (DS1--DS13)
/	  ARE AVAILABLE IN DBLFLT4.
	 
	 
/DBL4GO
/	THIS IS A REVISED VERSION OF DBL3GO.
/	DBL3GO CANNOT BE USED WITH DBLFLT4.
/	IN PROGRAMS WRITTEN TO USE DBLFLT3
/	  DBL3GO MUST BE REPLACED BY DBL4GO
/	  IN ORDER TO PROPERLY ACCESS
/	  DBLFLT4 ROUTINES.
	 
	 
/INDEX REGISTER UTILIZATION IN DBLFLT4:
/	DBLFLT4 SUBROUTINES USE INDEX
/	  REGISTERS 1--7, 12, AND 17
/	  IN THE MEMORY SEGMENT IN WHICH
/	  DBLFLT4 IS LOCATED.
/	USER PROGRAMS MAY USE IR.11 ? 13--16.
/	THESE REGISTERS MAY BE REFERENCED
/	  BY DBLFLT ARGUMENTS.
	 
	 
/END D4RULES
/
/
/