### FILE="Main.annotation"
## Copyright:	Public domain.
## Filename:	MYSUBS.agc
## Purpose:	Part of the source code for Colossus, build 249.
##		It is part of the source code for the Command Module's (CM)
##		Apollo Guidance Computer (AGC), for Apollo 9.
## Assembler:	yaYUL
## Reference:	Begins on p. 970.
## Contact:	Ron Burkey <info@sandroid.org>.
## Website:	www.ibiblio.org/apollo.
## Mod history:	08/25/04 RSB.	Began transcribing.
##		2017-01-06 RSB	Page numbers now agree with those on the
##				original harcopy, as opposed to the PDF page
##				numbers in 1701.pdf.
##		2017-01-15 RSB	Comment-text proofed by 3-way diff'ing vs
##				Colossus 237 and Comanche 55.  No differences
##				were found, so no corrections were made.
##		2021-05-30 ABS	EBANK= MPAC -> EBANK= KMPAC
##
## The contents of the "Colossus249" files, in general, are transcribed 
## from a scanned copy of the program listing.  Notations on this
## document read, in part:
##
##	Assemble revision 249 of AGC program Colossus by NASA
##	2021111-041.  October 28, 1968.  
##
##	This AGC program shall also be referred to as
##				Colossus 1A
##
##	Prepared by
##			Massachusetts Institute of Technology
##			75 Cambridge Parkway
##			Cambridge, Massachusetts
##	under NASA contract NAS 9-4065.
##
## Refer directly to the online document mentioned above for further information.
## Please report any errors (relative to the scanned pages) to info@sandroid.org.
##
## In some cases, where the source code for Luminary 131 overlaps that of 
## Colossus 249, this code is instead copied from the corresponding Luminary 131
## source file, and then is proofed to incorporate any changes.

## Page 970
		BANK	20
		SETLOC	MYSUBS
		BANK
		
		EBANK=	KMPAC
SPCOS1		EQUALS	SPCOS
SPSIN1		EQUALS	SPSIN
SPCOS2		EQUALS	SPCOS
SPSIN2		EQUALS	SPSIN
		COUNT	21/DAPMS
		
# ONE AND ONE HALF PRECISION MULTIPLICATION ROUTINE

SMALLMP		TS	KMPTEMP		# A(X+Y)
		EXTEND
		MP	KMPAC +1
		TS	KMPAC +1	# AY
		CAF	ZERO
		XCH	KMPAC
		EXTEND
		MP	KMPTEMP		# AX
		DAS	KMPAC		# AX+AY
		TC	Q
		
# SUBROUTINE FOR DOUBLE PRECISION ADDITIONS OF ANGLES
# A AND L CONTAIN A DP(1S) ANGLE SCALED BY 180 DEGS TO BE ADDED TO KMPAC.
# RESULT IS PLACED IN KMPAC.  TIMING = 6 MCT (22 MCT ON OVERFLOW)

DPADD		DAS	KMPAC
		EXTEND
		BZF	TSK +1		# NO OVERFLOW
		CCS	KMPAC
		TCF	DPADD+		# + OVERFLOW
		TCF	+2
		TCF	DPADD-		# - OVERFLOW
		CCS	KMPAC +1
		TCF	DPADD2+		# UPPER = 0, LOWER +
		TCF	+2
		COM			# UPPER = 0, LOWER -
		AD	POSMAX		# LOWER = 0, A = 0
		TS	KMPAC +1	# CAN NOT OVERFLOW
		CA	POSMAX		# UPPER WAS = 0
TSK		TS	KMPAC
		TC	Q
		
DPADD+		AD	NEGMAX		# KMPAC GREATER THAN 0
		TCF	TSK

## Page 971
DPADD-		COM
		AD	POSMAX		# KMPAC LESS THAN 0
		TCF	TSK
		
DPADD2+		AD	NEGMAX		# CAN NOT OVERFLOW
		TS	KMPAC +1
		CA	NEGMAX		# UPPER WAS = 0
		TCF	TSK

## Page 972
## This page is empty.