objnam BJSIZE.LIT ; created 3-Jan-85, last edited 4-Jan-85
; by Irv Bromberg, Medic/OS Consultants, Toronto, CANADA
; Medical and Operating Systems Software Consultants
RADIX 10
VEDIT=5
VMINOR=3
VMAJOR=1
VSUB=0

IF EQ,1

Under AMOS/L 1.3 BJSIZE.LIT 1.3(5) size=604 bytes, hash=654-363-176-350.

See BJMEM.DOC for more details.

Syntax: BJSIZE {bytes}{K}

Used only at system bootup time to set the boot job's memory partition
size to the specified amount.  AMOS/L normally allocates less than 32K
to the boot job, the actual amount being 32K minus BM.SIZ less the
size of DSK0:BADBLK.SYS[1,2], where BM.SIZ=size of the temporary DSK0:
Bitmap input/output Dataset Driver Block and flags (106 bytes under
AMOS/L 1.3).  This subtracted space is not needed after the first
DEVTBL command has been executed, thereafter the boot job's partition
can be increased to overlap this area.  The boot job's partition end is
at MEMEND so there is no need to move the bootup INI command file that
is being executed -- simply move the partition base JOBBAS(JCB) to the
new address and either clear all modules by writing a longword zero to
the new base address or create a temporary module and let EXIT delete it.

Restrictions:

BJSIZE will not change the boot job's partition before the first
DEVTBL command has been executed or after the first SYSTEM command.
As a precaution the valid range for partition size is 16K-64K bytes.

Default:

As a default BJSIZE will move the boot job's partition base exactly
32K bytes away from MEMEND.

Hints:

BJSIZE deletes all modules in the boot job's partition if the
New Size is less than (Old Size +12).  If the New Size is more
than 12 greater than the Old Size then BJSIZE creates a temporary
memory module between the new base and any modules that already
have been loaded.  When BJSIZE EXITs this temporary memory module
is deleted and any modules that have been loaded slide down to
the new base.  Thus as long as you are increasing the partition
size by more than 12 bytes no LOADed modules will be lost.

Warning:

Do not make the boot job's partition so large that another job's
partition will later overlap with it as it is allocated.

ENDC

SEARCH SYS
SEARCH SYSSYM

JCB=A0
Base=A1
Buffer=A2
Dev=A3
Atemp=A6

NewSize=D0
Number=D1
OldSize=D2
Diff=D3
Dtemp=D6

KB=1024

	PHDR	-1,0,PH$REE!PH$REU	; re-entrant & re-usable

	MOV	JOBCUR,JCB		; index this job's Job Control Block
	MOV	JOBTBL,Atemp		; check first job in JOBTBL
	MOV	@Atemp,Atemp
ChkJCB:	CMP	Atemp,JCB		; is this the boot job?
	BEQ	ChkSYS
	TYPECR	<?Only the boot job may execute this program>
	EXIT

ChkSYS:	MOV	SYSBAS,Number		; any SYSTEM modules loaded?
	BEQ	ChkDEV
	TYPECR	<?Must preceed any SYSTEM commands>
	EXIT

ChkDEV:	MOV	DEVTBL,Number		; has first DEVTBL been executed?
	CMP	Number,MEMBAS
	BLO	ChkSIZ
	TYPECR	<?Must not be used before DEVTBL command>
	EXIT

ChkSIZ:	MOV	#32*KB,Number		; pre-set default=32K
	LIN				; size specified?
	JEQ	ChkMem			; no, use default
	GTDEC				; yes, get specified size
	BMI	NoGood
	TST	Number			; could be 0 if syntax bad
	BNE	Kilo
NoGood:	TYPECR	<?Invalid partition size specified>
	EXIT

Kilo:	CMPB	@Buffer,#'K		; kilobytes specified?
	BNE	Even
	MUL	Number,#KB		; yes, multiply by 1K
Even:	INC	Number			; round up to even number
	BCLR	#0,Number
Chk64:	CMP	Number,#64*KB		; >64K?
	BLOS	Chk16
	TYPECR	<?Partition size cannot exceed 64K bytes>
	EXIT

Chk16:	CMP	Number,#16*KB
	BHIS	ChkMem
	TYPECR	<?Partition size cannot be less than 16K bytes>
	EXIT

ChkMem:	MOV	MEMEND,Dtemp
	SUB	MEMBAS,Dtemp
	CMP	Number,Dtemp
	BLO	ChkNew
	TYPECR	<?Insufficient memory available>
	EXIT

ChkNew:	MOV	Number,NewSize		; save a copy
	MOV	JOBSIZ(JCB),OldSize
	MOV	NewSize,Diff
	SUB	OldSize,Diff		; calculate the difference in size
	BNE	DoIt			; =0 if no change being made
	TYPE	<%Partition size is already>
	DCVT	0,OT$TRM!OT$LSP!OT$TSP
	TYPECR	<bytes, no action taken>
	EXIT

DoIt:	MOV	MEMEND,Base		; index end of physical memory
	SUB	NewSize,Base		; calculate new partition base addr
	MOV	Base,JOBBAS(JCB)	; set new partition base address
	MOV	NewSize,JOBSIZ(JCB)	; set new partition size
	CMP	Diff,#12
	BGE	MakeTMP			; take a signed comparison >=
	TYPECR	<%All memory modules deleted>
	CLR	@Base
	BR	ShowSize
MakeTMP:MOV	Diff,@Base		; make temporary module at base
	CLRW	4(Base)		; clear its flag word so EXIT will DEL it

ShowSize:MOV	NewSize,Number		; restore register for DCVT
	TYPE	<[>
	DCVT	0,OT$TRM!OT$TSP
	TYPE	<bytes allocated at >
	MOV	Base,Number		; copy for OCVT
	OCVT	0,OT$TRM
	TYPECR	<]>

	EXIT				; we did it!
	END
                          
.