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cobol/source/dpdiv.mac
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; UPD ID= 2056 on 10/24/79 at 3:08 PM by WRIGHT
TITLE DPDIV FOR LIBOL V12C
SUBTTL DOUBLE PRECISION DIVIDES AL BLACKINGTON/CAM
SEARCH COPYRT
SALL
;COPYRIGHT (C) DIGITAL EQUIPMENT CORPORATION 1974, 1985
;ALL RIGHTS RESERVED.
;
;THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED
;ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE.
;DMN 21-SEP-79 [606] FIX 4-WORD DIVIDE WHEN SIGN IS DIFFERENT
;V10******
; 5/10/75 /DBT ADD BIS CODE
;***********
SEARCH LBLPRM
%%LBLP==:%%LBLP
BIS==:BIS
HISEG
.COPYRIGHT ;Put COPYRIGHT statement in .REL file.
ENTRY DIV.12 ;DIVIDE ONE WORD BY TWO WORDS
ENTRY DIV.21 ;DIVIDE TWO WORDS BY ONE WORD
ENTRY DIV.22 ;DIVIDE TWO WORDS BY TWO WORDS
IFN BIS,<
ENTRY DIV.41 ;DIVIDE FOUR WORDS BY ONE WORD
ENTRY DIV.42 ;DIVIDE FOUR WORDS BY TWO WORDS
ENTRY DVI41. ;DIVIDE FOUR WORDS BY ONE WORD, SAVE REMAINDER
ENTRY DVI42. ;DIVIDE FOUR WORDS BY ONE WORD, SAVE REMAINDER
>
;CALLING SEQUENCE:
; MOVE 16,[Z AC,OPERAND]
; PUSHJ 17,DIV.12/DIV/21/DIV.22
;ENTER WITH DIVIDEND IN ACCUMULATORS AC&AC+1 FOR DIV.21&DIV.22,
; AND ACCUMULATOR AC FOR DIV.12.
;EXIT WITH QUOTIENT IN AC'S AC&AC+1,
; REMAINDER IN AC+2&AC+3 FOR DIV.12, DIV.22, REMAINDER IN AC+2 FOR DIV.21
FSIGN==1B18 ;SIGN FLAG JAMMED INTO PA
EXTERNAL OVFLO.
H1=13
H2=14
Q=4
QI=16
PA=16
PP=17
RS=15
TA=5
TB=TA+1
TC=TB+1
TD=TC+1
TE=TD+1
IFE BIS,<
DIV.21: SKIPN TD,0(PA) ;IS DIVISIOR ZERO?
JRST OVRFLO ;YES--SIZE ERROR
LDB RS,[POINT 4,PA,12]; GET OPERAND AC
PUSH PP, (RS) ;DO IT THIS WAY SO WE DON'T
MOVE TB, 1(RS) ; WIPE OUT THE FIRST WORD
POP PP, TA ; OF THE OPERAND.
PUSHJ PP,DIV21X ;DO THE DIVISION
MOVEM TA,0(RS) ;STASH HIGH PART
MOVEM TB,1(RS) ;STASH LOW PART
MOVEM TC,2(RS) ;STASH REMAINDER
POPJ PP,
DIV.12: LDB RS,[POINT 4,PA,12]; GET OPERAND AC
MOVE TA,0(RS) ;GET OPERAND
MULI TA,1 ;CONVERT TO DOUBLE PRECISION
JRST DIV220
DIV.22: LDB RS,[POINT 4,PA,12]; GET OPERAND AC
PUSH PP, (RS) ;DO IT THIS WAY SO WE DON'T
MOVE TB, 1(RS) ; WIPE OUT THE FIRST WORD
POP PP, TA ; OF THE OPERAND.
DIV220: SKIPGE TD,0(PA) ;IS DIVISOR NEGATIVE?
JRST DIV22B ;YES
MOVE TE,1(PA) ;NO--GET LOW-ORDER PART OF DIVISOR
DIV22A: TLZ TE,1B18 ;INSURE LOW-ORDER PART OF DIVISOR IS POSITIVE
JUMPN TD,DIV22C ;IS HI-ORDER PART OF DIVISOR ZERO?
JUMPE TE,OVRFLO ;YES--IS LOW-ORDER PART ZERO ALSO?
TLNN RS,FSIGN ;POSITIVE SIGN?
SKIPA TD,TE ;YES
MOVN TD,TE ;NO
PUSHJ PP,DIV21X ;DO THE DIVIDE
MULI TC,1 ;CONVERT REMAINDER TO 2-WORDS
MOVEM TA,0(RS) ;STASH
MOVEM TB,1(RS) ; QUOTIENT
MOVEM TC,2(RS) ;STASH
MOVEM TD,3(RS) ; REMAINDER
POPJ PP,
DIV22B: SETCA TD, ;DIVISOR IS NEGATIVE--GET MAGNITUDE
TLO RS,FSIGN ;SET SIGN TO NEGATIVE
MOVE TE,1(PA) ;GET LOW-ORDER PART OF DIVISOR
TLO TE,1B18 ;BE SURE IT'S ALSO NEGATIVE
MOVMS TE ;GET IT'S MAGNITUDE
JUMPG TE,DIV22A ;IF POSITIVE NOW--OK
;MUST HAVE BEEN ZERO
AOJGE TD,DIV22A ;IF HI-ORDER NOW POSITIVE--OK
JRST OVRFLO ;IT WASN'T--TROUBLE
;DIVIDEND IS NOW UNSIGNED IN TA&TB, DIVISOR UNSIGNED IN TD&TE
DIV22C: JUMPGE TA,DIV22E ;IS DIVIDEND POSITIVE?
TLC RS,FSIGN ;NO--COMPLEMENT SIGN OF RESULT
SETCA TA, ;COMPLEMENT HI-ORDER PART OF DIVIDEND
TLO TB,1B18 ;BE SURE LOW-PART AGREES IN SIGN
MOVMS TB ;NOW GET IT'S MAGNITUDE
JUMPG TB,DIV22F ;WAS LOW-ORDER PART ZERO?
;YES--BUMP HI-ORDER PART
AOJL TA,OVRFLO ;TOO BIG?
DIV22E: TLZ TB,1B18 ;BE SURE LOW-ORDER PART IS POSITIVE
DIV22F: MOVE H1,TA ;SAVE DIVIDEND
MOVE H2,TB
IDIV TA,TD ;DIVIDE HIGH-ORDER PARTS
MOVE Q,TA ;SAVE QUOTIENT
SKIPA QI,Q ;CREATE FIRST INCREMENT
DIV22G: MOVE TA,Q
LSH QI,-1 ;DIVIDE INCREMENT BY 2
SKIPN QI ;SAFETY
MOVEI QI,1 ; VALVE
MOVE TB,TA ;COMPUTE
IMUL TA,TD ; Q
MUL TB,TE ; TIMES
ADD TA,TB ; DIVISOR
SUBM H1,TA ;COMPUTE
SUBM H2,TC ; REMAINDER
SKIPGE TC
SUBI TA,1
TLZ TC,1B18
JUMPL TA,DIV22I ;IS REMAINDER NEGATIVE?
CAMG TA,TD ;NO--IS IT GREATER THAN DIVISOR?
JRST DIV22J ;MAYBE
DIV22H: ADD Q,QI ;REMAINDER GREATER THAN DIVISOR, TRIAL QUOTIENT TOO SMALL
JRST DIV22G
DIV22I: SUB Q,QI ;REMAINDER NEGATIVE, TRIAL QUOTIENT TOO BIG
JRST DIV22G
DIV22J: CAME TA,TD
JRST DIV22K
CAML TC,TE
JRST DIV22H
;ANSWER TO DIV.22 HAS BEEN FOUND
DIV22K: SKIPL 0(RS) ;IS DIVIDEND NEGATIVE?
JRST DIV22N ;NO
SETCA TA, ;YES--NEGATE REMAINDER
MOVNS TC
TLZ TC,1B18
SKIPN TC
ADDI TA,1
DIV22N: MOVE TD,Q ;GET QUOTIENT
TLNE RS,FSIGN ;NO--IS SIGN TO BE NEGATIVE?
MOVNS TD
MULI TD,1
DIV22L: SKIPL TA ;IS REMAINDER NEGATIVE?
TLZA TC,1B18 ;NO--FORCE LOW-PART TO BE POSITIVE
TLO TC,1B18 ;YES--FORCE LOW-PART TO BE NEGATIVE
DIV22P: SKIPL TD
TLZA TE,1B18
TLO TE,1B18
MOVEM TD,0(RS) ;STASH
MOVEM TE,1(RS) ; QUOTIENT
MOVEM TA,2(RS) ;STASH
MOVEM TC,3(RS) ; REMAINDER
POPJ PP,
;DO DIVIDE OF 2-WORD BY 1-WORD. DIVIDEND IN TA&TB, DIVISIOR IN TD.
;RETURN WITH QUOTIENT IN TA&TB, REMAINDER IN TC.
DIV21X: JUMPGE TA,DIV21Y ;POSITIVE DIVIDEND?
SETCA TA, ;NO--
MOVMS TB ; GET
TLZ TB,1B18 ; MAGNITUDE
SKIPN TB ; OF
ADDI TA,1 ; DIVIDEND
PUSHJ PP,DIV21Y ;DO DIVISION
MOVNS TC ;NEGATE REMAINDER
SETCA TA, ;NEGATE
MOVNS TB
TLZ TB,1B18 ; THE
SKIPN TB ; DOUBLE
ADDI TA,1 ; PRECISION
TLNE TA,1B18
TLO TB,1B18 ; QUOTIENT
POPJ PP,
DIV21Y: TLZ TB,1B18 ;BE SURE LOW-SIGN AGREES
MOVE TC,TB ;SAVE LOW-PART
IDIV TA,TD ;GET HIGH-PART OF QUOTIENT
DIV TB,TD ;GET LOW-PART OF QUOTIENT
SKIPGE TB
SUBI TA,1
POPJ PP,
> ;END OF NON-BIS
;DIVISION OVERFLOW -- SET INDICATOR
OVRFLO: SETOM OVFLO.
POPJ PP,
IFN BIS,<
DIV.21: MOVE H1,(PA) ;GET OPERAND
ASHC H1,-^D35 ;EXTEND SIGN
LDB RS,PACFL.## ;GET AC FIELD
DMOVE TC,(RS) ;GET SECOND OPERAND
MOVE TA,TC ;PROPAGATE THE SIGN
ASHC TA,-^D70
JOV .+1 ;CLEAR OVERFLOW.
DDIV TA,H1 ;DIVIDE
JOV OVRFLO ;CHECK OVERFLO
DMOVEM TA,(RS) ;STORE RESULT
MOVEM TD,2(RS) ;AND REMAINDER
POPJ PP,
DIV.12: LDB RS,PACFL.## ;GET AC
MOVE TD,(RS) ;GET OP 1
MOVE TA,TD ;PROPAGATE THE SIGN.
ASHC TA,-^D70
MOVE TC,TA
JOV .+1 ;CLEAR OVERFLOW.
DDIV TA,(PA)
JOV OVRFLO
DMOVEM TA,(RS) ;STORE QUOTIENT
DMOVEM TC,2(RS) ;AND REMAINDER
POPJ PP,
DIV.22: LDB RS,PACFL.## ;GET AC
DMOVE TC,(RS) ;GET OP
MOVE TA,TC ;PROPAGATE THE SIGN.
ASHC TA,-^D70
JOV .+1 ;CLEAR OVERFLOW.
DDIV TA,(PA)
JOV OVRFLO
DMOVEM TA,(RS)
DMOVEM TC,2(RS)
POPJ PP,
;DIVIDES THE FOUR WORD INTEGER IN ACC 0-3
;LEAVING THE QUOTIENT IN ACC 0-3, REMAINDER IN ACC 4&5
DIV.41: MOVE H1,(PA) ;GET OPERAND
ASHC H1,-^D35 ;EXTEND SIGN
JRST DIV.4X ;COMMON CODE
DIV.42: DMOVE H1,(PA) ;INCASE (PA) = 6
DIV.4X: DMOVE 4,2 ;COPY LOW ORDER 2 WORDS
DMOVE 2,0 ;COPY HIGH ORDER 2 WORDS
ASHC 0,-^D70 ;EXTEND THE SIGN
JOV .+1 ;CLEAR OVERFLOW.
DDIV 0,H1 ;DIVIDE HIGH ORDER 2 WORDS
JOV OVRFLO
DDIV 2,H1 ;AND LOW ORDER
JUMPN 0,RET.1## ;[606] IF THE HIGH ORDER PART
JUMPN 1,RET.1 ;[606] IS ZERO
JUMPGE 2,RET.1 ;[606] BUT THE LOW ORDER PART IS NEGATIVE
SETOB 0,1 ;[606] EXTEND THE SIGN
POPJ PP,
;ROUTINES CALLED BY:
; MOVEI 15,<ADDRESS.OF.FOUR-WORD.NUMBER>
; MOVEI 16,[POWER OF 10]
; PUSHJ PP,ROUTINE
; <RETURN HERE>, WITH 2-WORD REMAINDER SAVED IN 0(15) AND 1(15).
DVI41.: MOVE H1,(PA) ;GET OPERAND
ASHC H1,-^D35 ;EXTEND SIGN
JRST DIVI4X
DVI42.: DMOVE H1,(PA) ;GET OPERAND
;USE 6 ACS - 4 THRU 11
;AC15 WILL EITHER POINT TO AC0, OR %TEMP
DIVI4X: DMOVE 10,2(15) ;COPY LOW ORDER 2 WORDS
DMOVE 6,(15) ;COPY HIGH ORDER 2 WORDS
ASHC 4,-^D70 ;EXTEND THE SIGN
JOV .+1 ;CLEAR OVERFLOW
DDIV 4,H1 ;DIVIDE HIGH ORDER 2 WORDS
JOV OVRFLO
DDIV 6,H1 ;AND LOW ORDER
DMOVEM 10,(15) ;SAVE REMAINDER
POPJ PP, ;RETURN
> ;END OF BIS
END