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Trailing-Edge - PDP-10 Archives - bb-h138f-bm - 7-sources/ipagen.mac
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;WORK:<GSCOTT.IPA>IPAGEN.MAC.189 29-Sep-87 18:02:25, Edit by GSCOTT
;(17) Bug in last edit.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.186 29-Sep-87 17:59:03, Edit by GSCOTT
;(16) Stupid coding error was smashing the microwords that load the version.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.185 29-Sep-87 16:22:00, Edit by GSCOTT
;(15) Account for monitor storing version incorrectly in UCDVER
;WORK:<GSCOTT.IPA>IPAGEN.MAC.183 29-Sep-87 15:57:00, Edit by GSCOTT
;(14) Move text to literal for IMOK.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.180 29-Sep-87 15:56:29, Edit by GSCOTT
;(13) Get version number from entry vector
;WORK:<GSCOTT.IPA>IPAGEN.MAC.177 29-Sep-87 15:49:34, Edit by GSCOTT
;(12) Output version number even if user is starting.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.170 29-Sep-87 13:22:59, Edit by GSCOTT
;(11) Add some more comments about program use.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.167 29-Sep-87 13:07:06, Edit by GSCOTT
;(10) Rearrange storage, put a WARNING in about the memory layout.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.157 28-Sep-87 22:50:36, Edit by GSCOTT
;(7) Clean up listing
;WORK:<GSCOTT.IPA>IPAGEN.MAC.152 28-Sep-87 22:35:13, Edit by GSCOTT
;(6) Dump JFN of CI20 file properly.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.146 28-Sep-87 22:22:43, Edit by GSCOTT
;(5) Set starting address after microcode loaded.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.140 28-Sep-87 22:08:31, Edit by GSCOTT
;(4) Rearrange storage so that old monitors can still use new IPAGEN.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.132 28-Sep-87 17:51:00, Edit by GSCOTT
;(3) Store version number in entry vector
;WORK:<GSCOTT.IPA>IPAGEN.MAC.129 28-Sep-87 17:42:26, Edit by GSCOTT
;(2) Insert SKIPAs before DIAG for debugging.
;WORK:<GSCOTT.IPA>IPAGEN.MAC.3 28-Sep-87 11:47:30, Edit by GSCOTT
;(1) Creation.

	TITLE IPAGEN - Generate IPALOD for loading CI20 microcode 
	SUBTTL Gregory A. Scott
	Subttl	Table of Contents

;		     Table of Contents for IPAGEN
;
;				  Section		      Page
;
;
;    1. Use of this program  . . . . . . . . . . . . . . . . .   3
;    2. Definitions  . . . . . . . . . . . . . . . . . . . . .   4
;    3. Startup  . . . . . . . . . . . . . . . . . . . . . . .   5
;    4. Have monitor load microcode  . . . . . . . . . . . . .   6
;    5. Load microcode file into memory  . . . . . . . . . . .   7
;        5.1    Loop to load ucode buffer  . . . . . . . . . .   8
;        5.2    Finish up ucode buffer . . . . . . . . . . . .   9
;        5.3    Save loaded image  . . . . . . . . . . . . . .  10
;        5.4    Close files and exit . . . . . . . . . . . . .  11
;    6. Read line of microcode . . . . . . . . . . . . . . . .  12
;    7. Subroutines  . . . . . . . . . . . . . . . . . . . . .  15
;    8. Storage
;        8.1    Pure . . . . . . . . . . . . . . . . . . . . .  16
;        8.2    Impure . . . . . . . . . . . . . . . . . . . .  17
;    9. End of IPAGEN  . . . . . . . . . . . . . . . . . . . .  19
	SUBTTL Use of this program

	COMMENT ~

This program is used to generate the file IPALOD.EXE, which resides in
PS:<SYSTEM> of a TOPS-20 system to load the CI20 microcode.  To use it,
perform the following steps:

	1) Copy the desired microcode into a file called CI20.ULD.
	2) Run IPAGEN, it then loads the microcode.  IPAGEN saves itself in
	   the file IPALOD.EXE.edit, where "edit" is the microcode's edit.
	3) Copy the resultant IPALOD.EXE.edit into PS:<SYSTEM>
	4) Reload the system.

An IPALOD.EXE can also generate another IPALOD by having a CI20.ULD in the
connected directory.  To do this:

	1) Copy the desired microcode into a file called CI20.ULD.
	2) GET PS:<SYSTEM>IPALOD, and then REENTER it.  IPALOD then loads
	   the microcode and saves itself in the file IPALOD.EXE.edit,
	   where "edit" is the microcode's edit number.
	3) Copy the resultant IPALOD.EXE.edit into PS:<SYSTEM>
	4) Reload the system.

PHYKLP reads the file PS:<SYSTEM>IPALOD.EXE early in its KLIPA initialization
code and store the microcode in extended resident memory.  Job 0 then starts
up IPALOD at entry vector offset 4, causing two DIAG JSYSes to be executed
which load the microcode from the copy in memory.  When a user runs IPALOD
(entry vector offset 0) the same two DIAG JSYSes are executed.  Entry vector
offset 1 (REENTER) is used to load a new CI20 microcode into memory and then
save it.  Entry vector offset 3 contains the version of the microcode loaded.

	END OF COMMENT ~
	SUBTTL Definitions

;Search the usual things, set up the usual AC defs

	SEARCH MONSYM,MACSYM	;Search the usual universals
	SALL			;Clean listing
	STDAC.			;Standard ACs today
	.DIREC FLBLST		;First line binary listing please
	SALL			;Clean listing

;Version of KLPLOD

VMAJ==1				;Major version
VMIN==0				;Minor version
VEDI==17			;Edit
VWHO==0				;Who else but DEC development?

	LOC 400000		;Get us out of the monitor's way
	SUBTTL Startup

;Two entry points are used: one for the monitor, and one for the user.

MSTART:	TDZA P2,P2		;Monitor starts here
USTART:	SETO P2,		;User starts here

;Set up the stack, and enter user i/o mode (not sure why you need to do that).

	MOVE P,[IOWD PDLEN,PDL]	;Load up the stack
	USRIO%			;Get into user I/O mode to deal with KLIPA
	ERJMP UFAIL		;Punt if error
	JUMPE P2,MLOAD		;Jump if monitor loading it

;User is loading CI20 microcode - we don't know what version he will get today

ULOAD:	MOVEI T1,.SNPSY		;Get a monitor symbol
	MOVE T2,[RADIX50 0,UCDVER] ;This is where the version is stored
	MOVE T3,[RADIX50 0,PHYKLP] ;This is where that symbol lives
	SNOOP%			;Get the value of that symbol
	ERJMP ULOAD2		;Oops, forget it
	MOVEI T1,(T2)		;Section 0 address of the data
	HRLI T1,1		;One word today
	MOVEI T2,T4		;Store it in T3
	PEEK%			;Get word from monitor into T4
	ERJMP ULOAD2		;Punt if error
	HRROI T1,[ASCIZ/[IPALOD: Reloading resident CI20 microcode version /]
	PSOUT%			;Telling me that is easy enough
	CALL PVERS1		;(T4/) Print ucode version
	CALL CLOSB		;() Output close bracket
	JRST LOADIT		;Try and loadit

ULOAD2:	HRROI T1,[ASCIZ/[IPALOD: Reloading resident CI20 microcode]/]
	PSOUT%			;Telling me that is easy enough
	JRST LOADIT		; and then try and load it

;Here if the monitor is running us, output the version of the ucode loading.

MLOAD:	HRROI T1,[ASCIZ/
[IPALOD: Loading CI20 microcode version /] ;Start of the message
	PSOUT%			;Telling me that is easy enough
	CALL PVERS		;() Print ucode version
	CALL CLOSB		;() Output close bracket
				;Fall through to LOADIT
	SUBTTL Have monitor load microcode

;Here to load the microcode that the monitor has picked out of us earlier.

LOADIT:	MOVE T1,[-2,,[EXP .DGUCD,.DGRIP]] ;Get reload ucode function
	DIAG%			;Ask the monitor to do it for us
	ERJMP LFAIL		;Fail if it didn't work properly
	CALL IMOK		;() Output the OK message
	MOVE T1,[-2,,[EXP .DGUCD,.DGRLC]] ;Reload is now complete
	DIAG%			;Tell the monitor
	ERJMP .+1		;Ignore errors

;Done, halt this fork

UEXIT:	HALTF%			;That's all
	 JRST .-1		;Prevent restarts

;Here if the loading failed

LFAIL:	HRROI T1,[ASCIZ/ [FAILED]
/]				;Load failed message
	PSOUT%			;Output that message

UFAIL:	HRROI T1,[ASCIZ/IPALOD: /] ;Start the error string out
	ESOUT%			; on the terminal
	CALL PERROR		;() Dump the last error
	JRST UEXIT		;Exit the program
	SUBTTL Load microcode file into memory

;Here to read the microcode from a file and store it in UCBUFF.

READIT:	RESET%			;Reset the world
	MOVE P,[IOWD PDLEN,PDL]	;Load up the stack

;Get a open JFN on the file.

	MOVX T1,GJ%SHT!GJ%OLD	;Load short form old file
	HRROI T2,[ASCIZ/CI20.ULD/] ;Standard filename
	GTJFN%			;Get a JFN for it
	ERJMP RFAIL1		;Read failed
	MOVX T2,FLD(7,OF%BSZ)!OF%RD ;Open for 7 bit bytes and reading
	OPENF%			;Pry it open
	ERJMP RFAIL2		;Punt if it didn't work
	MOVEM T1,RJFN		;Store the JFN

;Let me know what file I am reading today.

	HRROI T1,[ASCIZ/[IPAGEN: Reading /] ;Load a label
	PSOUT%			;Output that
	MOVE T2,RJFN		;Copy JFN back to T2
	MOVEI T1,.PRIOU		;Output to primary
	MOVX T3,FLD(.JSAOF,JS%DEV)!FLD(.JSAOF,JS%DIR)!FLD(.JSAOF,JS%NAM)!FLD(.JSAOF,JS%TYP)!FLD(.JSAOF,JS%GEN)!JS%PAF
	JFNS%			;Output that
	ERJMP .+1		;Can't fail
	CALL CLOSB		;() Output close bracket
	SUBTTL Load microcode file into memory -- Loop to load ucode buffer

;Microcode file is open, read it scanning the important lines.  P1 will point
;to the location in UCBUFF, P2 will hold the number of microwords that we are
;storing.  Microcode location 135 holds the major version number in bits 21-23
;and minor version in bits 24-29.  Microcode location 137 holds the edit number
;in bits 20-29, which is stored for the monitor's use later.

	SETZB P1,P2		;Clear both of them
RLOOP:	CALL GUCODE		;(/Q1,Q2,Q3,T4) Get a microword
	 JRST RFINI		;Finish up
	CAIE T4,136		;Version word?
	IFSKP.			;Yes
	  MOVE T2,Q2		;Copy the word to T2
	  LSH T2,-6		;Shift down
	  MOVEI T3,(T2)		;Copy the whole version over
	  ANDI T3,77		;Get just the minor version
	  LSH T2,-6		;Shift down the major version
	  ANDI T2,7		;Zap the junk away
	  MOVEM T2,UVERS	;Store major version
	  MOVEM T3,UMINO	;Store 
	ENDIF.
	CAIE T4,137		;Edit word?
	IFSKP.			;Yes
	  MOVE T2,Q2		;Copy the word over to T2 
	  LSH T2,-6		;Shift down
	  ANDI T2,3777		;Get just the edit number
	  MOVEM T2,UEDIT	;Store edit number
	ENDIF.
	DMOVEM Q1,UCBUFF(P1)	;Store Q1 and Q2
	MOVEM Q3,UCBUFF+2(P1)	; and Q3
	ADDI P1,3		;Point to next free word
	AOJA P2,RLOOP		;Continue until all has been read
	SUBTTL Load microcode file into memory -- Finish up ucode buffer

;Here when end of file detected, finish buffer with words containing -1, major,
;minor, and edit for the monitor's use.

RFINI:	MOVEM P1,WORDS		;Save number of words loaded today
	SETOM UCBUFF(P1)	;Put a -1 at end of microcode stored
	DMOVE T1,UVERS		;Get major and minor version
	DMOVEM T1,UCBUFF+1(P1)	;Store major and minor version for monitor
	DPB T1,[POINT 9,VERSIO,11] ;Store the major version in entry vector
	DPB T2,[POINT 6,VERSIO,17] ;Store minor version in entry vector
	MOVE T1,UEDIT		;Load edit number
	MOVEM T1,UCBUFF+3(P1)	;Store the edit number for monitor
	HRRM T1,VERSIO		;Store edit number in entry vector
	MOVEI T1,USER		;Load user starting address
	HRRM T1,ENTRY		;Store it in the entry vector

;Say what version we loaded today.

	CALL IMOK		;() Output OK message
	HRROI T1,[ASCIZ/[IPAGEN: /] ;Output next label
	PSOUT%			;Output that next
	MOVEI T1,.PRIOU		;Output to primary
	MOVE T2,WORDS		;Get number of words
	IDIVI T2,3		;Account for 3 of our words for each of his
	MOVEI T3,^D10		;Radix ten
	NOUT%			;Output that
	ERJMP .+1		;Punt errors
	HRROI T1,[ASCIZ/ microwords loaded, version /]
	PSOUT%			;Output that
	CALL PVERS		;() Output what version
	CALL CLOSB		;() Output closing bracket
	SUBTTL Load microcode file into memory -- Save loaded image

;Create filename and save it.

	HRROI T1,FBUFF		;Make the filename next
	HRROI T2,[ASCIZ/IPALOD.EXE./] ;Start with the name
	SETZB T3,T4		;Terminate on a null
	SOUT%			;String OUTput that (slow, dumb)
	MOVE T2,UEDIT		;Load edit number
	MOVEI T3,10		;Load radix 8
	NOUT%			;Output that number
	ERJMP .+1		;Punt any errors away
	MOVX T1,GJ%SHT!GJ%FOU	;Load short form bit
	HRROI T2,FBUFF		;Point back to the filename
	GTJFN%			;Get a JFN on it
	ERJMP RFAIL3		;Punt if failure
	MOVE T2,T1		;Copy JFN back to T2
	HRROI T1,[ASCIZ/
[IPAGEN: Saving as /]		;Load a label
	PSOUT%			;Output that
	MOVEI T1,.PRIOU		;Output to primary
	MOVX T3,FLD(.JSAOF,JS%DEV)!FLD(.JSAOF,JS%DIR)!FLD(.JSAOF,JS%NAM)!FLD(.JSAOF,JS%TYP)!FLD(.JSAOF,JS%GEN)!JS%PAF
	JFNS%			;Output that
	ERJMP .+1		;Can't fail
	CALL CLOSB		;() Output close bracket
	MOVEI T1,(T2)		;Get JFN back to T2
	HRLI T1,.FHSLF		;Make fork,,JFN 
	MOVE T2,[-1000,,SS%CPY!SS%RD!SS%EXE] ;All of the pages this fork
	SETZ T3,		;No additional data
	SSAVE%			;Save us
	ERJMP RFAIL4		;Punt if failure
	CALL IMOK		;() OK
				;Fall through to RCLOSE
	SUBTTL Load microcode file into memory -- Close files and exit

;Here to close JFNs and exit.

RCLOSE:	SKIPE T1,RJFN		;Do we have a JFN?
	CLOSF%			;Close it
	ERJMP .+1		;Ignore errors
	SETZM RJFN		;Remember that we dumped the JFN
	HALTF%			;Stop
	JRST .-1		;Don't continue

;Here when there is a problem, report it

RFAIL4:	JSP T1,RFAIL0		;Here if can't open file
	ASCIZ/IPAGEN: Can't save IPALOD.EXE - /
RFAIL3:	JSP T1,RFAIL0		;Here if can't open file
	ASCIZ/IPAGEN: Can't get JFN for IPALOD.EXE - /
RFAIL2:	JSP T1,RFAIL0		;Here if can't open file
	ASCIZ/IPAGEN: Can't open CI20.ULD - /
RFAIL1:	JSP T1,RFAIL0		;Here if can't get jfn
	ASCIZ/IPAGEN: Can't get JFN for CI20.ULD - /

RFAIL0:	TLO T1,-1		;Make -1,,address
	ESOUT%			;Output that string
	CALL PERROR		;() Print the error
	JRST RCLOSE		;Dump JFN and exit
	SUBTTL Read line of microcode

;Here to read a word of microcode from the file.  The format of the file is as
;follows.  If the first character on a line is not a "[" then this line is not
;part of the microcode.  The number following the "[" is the location that this
;microword is for.  After the location comes a "]=".  The actual microword is
;next.  A CRLF terminates the line.
;
;Assumes that ULD file is open and JFN points at beginning of line.
;
;Returns: never if some error
;	  +1 if end of file
;	  +2 if microword found with
;		Q1/ first load format word
;		Q2/ second load format word
;		Q3/ third load format word
;		T4/ address of this microword

GUCODE:	MOVE T1,RJFN		;Load the JFN of the file
	BIN%			;Get a 7 bit byte
	ERJMP GCHECK		;Check error
	CAIN T2,"["		;Start of microcode line?
	JRST GUC1		;Yes

;Not a microcode load line, eat until end of line seen

GUC0:	BIN%			;Get a character
	ERJMP GCHECK		;Check if error
	CAIE T2,.CHLFD		;Line feed?
	JRST GUC0		;Nope, loop for more
	JRST GUCODE		;Rough and ready to ride again

;Read in the microaddress, save it in T4

GUC1:	MOVEI T3,10		;Load octal radix
	NIN%			;Input that number to T2
	ERJMP GCHECK		;Check errors
	MOVE T4,T2		;Copy address to T4

;Check for next two characters being "]" and "="

	BKJFN%			;Get the termination character back please
	ERJMP GCHECK		;Check for errors
	BIN%			;Get next character
	ERJMP GCHECK		;Check errors
	CAIE T2,"]"		;Closed properly?
	JRST GCFERR		;Nope
	BIN%			;Get next character
	ERJMP GCHECK		;Check errors
	CAIE T2,"="		;Formatted properly?
	JRST GCFERR		;Nope
;Format Q1 with the address and select bits (B0!<addr>B12!B13)

	MOVEI Q1,(T4)		;Copy the address
	LSH Q1,^D35-^D12	;Shift properly
	TXO Q1,1B0!1B13		; and set the constant bits

;Read the microword into memory, splitting it into two ten character pieces

	HRROI T2,RBUFF1		;Point to read buffer
	MOVNI T3,^D10		;Reading ten characters today
	SIN%			;Read them
	ERJMP GCHECK		;Check errors
	HRROI T2,RBUFF2		;Point to read buffer
	MOVNI T3,^D10		;Reading ten characters today
	SIN%			;Read them
	ERJMP GCHECK		;Check errors

;Insure that there is a CR LF pair at the end of the line

	BIN%			;Get the next character
	ERJMP GCHECK		;Check errors
	CAIE T2,.CHCRT		;Is it a return
	JRST GCFERR		;No, format error
	BIN%			;Get the next character
	ERJMP GCHECK		;Check errors
	CAIE T2,.CHLFD		;Is it a return
	JRST GCFERR		;No, format error

;Convert the ASCIZ numbers in the read buffers to numbers for storage

	HRROI T1,RBUFF1		;Point to the first word 
	MOVEI T3,10		;Octal radix
	NIN%			;Read that
	ERJMP GCHECK		;Check errors
	MOVE Q2,T2		;Copy data to Q2
	HRROI T1,RBUFF2		;Point to the second word 
	NIN%			;Read that
	ERJMP GCHECK		;Check errors
	MOVE Q3,T2		;Copy data to Q3

;All went well, so we can return now

RSKP:	AOS (P)			;Skip and
R:	RET			; return
;Here on a format error

GCFERR:	HRROI T1,[ASCIZ/IPAGEN: Format error with file
/]
	ESOUT%			;Output that error
	JRST RCLOSE		;Lose JFN and exit

;Here on a ERJMP from a JSYS while reading the file

GCHECK:	MOVEI T1,.FHSLF		;Load this fork's JFN
	GETER%			;Get that error
	TLZ T2,-1		;Zap the fork
	CAIN T2,IOX4		;End of file reached?
	RET			;Yes, return+1 now
	HRROI T1,[ASCIZ/IPAGEN: IO error reading microcode file - /]
	ESOUT%			;Output that string
	CALL PERROR		;() Print whatever error it was
	JRST RCLOSE		;() Lose JFN and exit
	SUBTTL Subroutines

;Small routine to print OK message

IMOK:	HRROI T1,[ASCIZ/ [OK]
/]				;Output the OK message
	PSOUT%			; to the terminal
	RET			;  and return

;Small routine to print closing bracket

CLOSB:	MOVEI T1,"]"		;Output ending square bracket
	PBOUT%			; to the terminal
	RET			;  and return

;Small routine to print out the last JSYS error

PERROR:	MOVEI T1,.PRIOU		;Output to terminal
	HRLOI T2,.FHSLF		;This fork's last error
	SETZ T3,		;No limit
	ERSTR%			;Output the string to terminal
	 JFCL			;Forget 
	 JFCL			; any errors
	RET			;  and return

;Small routine to print microcode version

PVERS:	MOVE T4,VERSIO		;Print version from entry vector
PVERS1:	MOVEI T1,.PRIOU		;Output to primary
	LDB T2,[POINT 9,T4,11]	;Load the major version
	CAIN T2,10		;Is it version 10?
	MOVEI T2,1		;Yes, it is really version 1
	MOVEI T3,10		;Octal radix
	NOUT%			;Output that number
	ERJMPS .+1		;Ignore error, preserve T1
	LDB T2,[POINT 6,T4,17]	;Get minor version
	JUMPE T2,PVERS2		;Jump if none
	MOVEI T2,"."		;Load a dot
	BOUT%			;Output it
	ERJMPS .+1		;Ignore error, preserve T1
	LDB T2,[POINT 6,T4,17]	;Get minor version again
	NOUT%			;Output that
	ERJMPS .+1		;Ignore error, preserve T1
PVERS2:	MOVEI T2,"("		;Output paren
	BOUT%			; to terminal
	ERJMPS .+1		;Ignore error, preserve T1
	MOVEI T1,.PRIOU		;Output to primary
	HRRZ T2,T4		;Load edit number
	NOUT%			;Output that number
	ERJMPS .+1		;Ignore error, preserve T1
	HRROI T1,[ASCIZ/)/]	;End that text
	PSOUT%			;Output that and fall thru
	RET			;Return
	SUBTTL Storage -- Pure

;Dump literals (XLISTed)

LIT..:	XLIST			;LIT
	LIT
ELIT..:	LIST
	SUBTTL Storage -- Impure

;                                   WARNING

;CAUTION: If you change any locations in low memory, you have to change PHYKLP
;so that it works right - the KLPUCD routine to which does a RIN% with 1146 in
;AC3 to pick up what is in location WORDS below.  WORDS should equal location
;146 in the image saved, and should be the 1146th word in the file.  The
;microcode is read in starting at word 2000.  Since page 0 of the EXE file is
;the EXE file directory, and page 1 of the EXE file must be page 0 of the
;memory image, and page 2 start the microcode, there cannot be anything in page
;1 of the image before it is saved.  This means that the layout of the first
;few pages of the EXE file must be:
;
;	Page 0	EXE file directory
;	Page 1	Entry vector, code startup (memory page 0)
;	Page 2	Start of microcode (memory page 2)
;	Page 31	End of microcode (memory page 31)
;		The foramt of the rest of the EXE file doesn't matter.

	LOC 140			;Start here

;Entry vector 

ENTRY:	JRST READIT		;(replaced with JRST USER)
	JRST READIT		;User wants to read new microcode
VERSIO:	BYTE (3)VWHO(9)VMAJ(6)VMIN(18)VEDI ;Version
	JRST MONITR		;Monitor wants microcode loaded

;Start locations

USER:	JRST USTART		;User tries to run IPALOD comes here
MONITR:	JRST MSTART		;Monitor loads CI microcode at system startup
WORDS:	Z			;Monitor looks here for number of words 

;End of CAUTION
;Other impure storage goes here

PDL:	BLOCK <PDLEN==10>	;The stack
UVERS:	BLOCK 1			;Microcode major version
UMINO:	BLOCK 1			;Microcode minor version
UEDIT:	BLOCK 1			;Microcode edit
RJFN:	BLOCK 1			;JFN of microcode file we are reading
RBUFF1:	BLOCK 3			;Place to read firsthalf of microword into
RBUFF2:	BLOCK 3			;Place to read second half of microword into
FBUFF:	BLOCK <^D20/5>		;Place to create filename

;The microcode is wired in starting at location 2000, and there can't be a page
;1 in the pagemap (see previous page's WARNING).  Don't let an overflow occur
;to page 1.

FREE==.				;Beginning of page 0 free space
IF1,IFG FREE-777,<PRINTX ?Storage overflows location 777>

	LOC 2000
UCBUFF:	BLOCK ^D4097*3	;4K ucode storage, 3 words for each uword
	BLOCK 4		;Space for -1 and version information
	SUBTTL End of IPAGEN

	END <4,,ENTRY>