Forming a Pascal System Booter
------------------------------



	To create an UCSD Pascal system booter you must have the following:

		1)  A short boot loader that will read in track 0 sectors 2 - 13

		2)  A copy of PINIT.ASM

		3)  A hex version of your current BIOS

		4)  A copy of PGEN.COM


	The short boot loader of 1) can be generated from your current system
boot loader if either a source or listing of it is available.  This trans-
formation process is simply the reduction of a two track bootstrap into a
single track one.  Two programs BOOT.ASM and PBOOT.ASM are provided as inspir-
ation for this proceedure.


	NOTE:  PBOOT loads its sectors to location (MSIZE-48)*1024+0BA00H
	       and then jumps to that same point.


	If you have no inkling of how your current system boot either loads or
works, you will have to prevail on your system supplier for that information.


	PINIT.ASM is the source for the code that boots in and starts
SYSTEM.MICRO, the P-Machine interpreter.  A quick edit of PINIT.ASM is needed
to modify the MSIZE equate to match the memory size (in kilobytes) of the
current system BIOS.  Once this has been done each of the modules PBOOT, PINIT
and BIOS must be assembled to produce the .HEX files which will be overlayed
into PGEN's data area as follows:

	NOTE:  In the following we assume a 48k system



A>DDT PGEN.COM			;Read PGEN code into memory

DDT VERS 1.3			;We will be overlaying PBOOT,
NEXT  PC			;  PINIT, and BIOS into PGEN's
0300 0100			;  data area, and finally saving
				;  the memory image.
-IPBOOT.HEX			;Set 'PBOOT.HEX' as the input file
-H900 0				;PBOOT starts at location 0,  we want
0900 0900			;  to compute a bias to read it to loc 900
-R900				;Using this bias we read PBOOT to PGEN's
NEXT  PC			;  data area
0980 0000
-IPINIT.HEX			;We will now do the same proceedure with
-H980 BA00			;PINIT.  This object code will go to
C380 4F80			;  location 980, notice PINIT starts at
-R4F80				;  BA00 (HEX) in a 48k system.
NEXT  PC
0A7D BA00			;The value below NEXT will vary with the release
-IBIOS.HEX			;Last we read BIOS to location D80
-HD80 BE00
C380 4F80			;This should be the same bias value as last time
-R4F80
NEXT  PC
0F76 0000			;The value below NEXT is dependant on BIOS
-^C				;We now leave ddt to save our work

A>SAVE 16 PGEN48.COM		;Our boot writer will be called PGEN48
A>PGEN48			;The booter may now be put out to Pascal

PGEN VERSION 1.0		;  system disks by executing PGEN48

GET BOOTER?(Y/N)N		;  as shown

PUT BOOTER?(Y/N)Y
WRITING BOOTER TO DRIVE A, TYPE RETURN
AGAIN?(Y/N)N

REBOOTING CP/M, TYPE RETURN

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