{"id":1058,"date":"2019-04-12T03:00:17","date_gmt":"2019-04-12T10:00:17","guid":{"rendered":"https:\/\/www.pagetable.com\/?p=1058"},"modified":"2019-04-12T03:00:17","modified_gmt":"2019-04-12T10:00:17","slug":"reconstructing-the-unreleased-c128-rom-update","status":"publish","type":"post","link":"https:\/\/www.pagetable.com\/?p=1058","title":{"rendered":"Reconstructing the Unreleased C128 ROM Update"},"content":{"rendered":"

The C128 source dump over at zimmers.net<\/a> that appeared recently contains source for a version 2 kernel, which was never released. The known versions are 0 and 1. Let’s see whether we can reconstruct the ROM image!<\/p>\n

Release Notes<\/h2>\n

These are the release notes for the version 2 C128 KERNAL:<\/p>\n

         C128 ROM RELEASE NOTES: 318020-06\n                                 318023-03\n\n\nTHE FOLLOWING MODIFICATIONS HAVE BEEN MADE TO THE 318020-05 KERNEL  CODE TO\nCREATE A NEW ROM SET RELEASED ON 05\/30\/88.  THIS  RELEASE IS FOR USE IN THE\nFOLLOWING SYSTEMS:  C128, C128D, C128CR, C128DCR.  ROMS WILL BE BUILT FOR\nONLY THE CURRENT 32K BYTE \"CR\" SYSTEMS, HOWEVER (318023-03).\n\n   1.  # 318023-03 --> EDITOR, KERNEL, CP\/M ($C000-$FFFF, U32) cksum= E424\n   2.  # 318020-06 --> EDITOR, KERNEL, CP\/M ($C000-$FFFF)      cksum= DFC4\n\n       1.  SECURE.  This kernel initialization routine has been modified\n           to accomodate technological advances in DRAMs.  The discharge\n           rates for data cells has lengthened considerably and it is no\n           longer possible to rely upon the  loss  of data as indicative\n           of a  power cycle as opposed to a  reset.  The SECURE routine\n           has been patched to also check the  contents of the  8568 VDC\n           registers.  These will  contain  $FF  if  power  cycled.  The\n           previous  testing of a \"CBM\" RAM key in  bank one remains for\n           compatability.  This patch required new code in patch area.\n\n       2.  DLABYE.  This kernel  serial  I\/O routine has been patched to\n           provide a longer delay.  This should prevent certain randomly\n           occurring DEVICE NOT READY errors, particularly at 2MHz. This\n           is a single byte patch totally inline.\n\n       3.  OPN232.  This kernel  routine  has  been patched to correctly\n           return error status.  When  implementing  an X-line interface\n           it was possible to receive an error when there was none. This\n           is a single byte patch totally inline.\n\n       4.  The ROM  signature at location $CFFC  and  $CFFD  (lo\/hi)  is\n           $8C3E.\n\n       5.  The ROM revision byte at location $CFFE, has incremented from\n           $01 to $02.\n\n       6.  The ROM checksum byte at  location  $CFFF,  has  changed from\n           $3C to $3B.\n\n       7.  The Kernel revision byte at location  $FF80  has  incremented\n           from $01 to $02.\n\n\n       Fred Bowen        05\/30\/88.\n<\/code><\/pre>\n
The “31802x-0y” numbers are Commodore Product IDs for the physical ROM chips:<\/p>\n\n\n\n\n\n\n\n\n
 Product ID <\/th>\n System     <\/th>\n Description                <\/th>\n Size  <\/th>\n Status     <\/th>\n<\/tr>\n<\/thead>\n
 318020-05  <\/td>\n C128\/C128D <\/td>\n KERNAL version 2           <\/td>\n 16 KB <\/td>\n released   <\/td>\n<\/tr>\n
 318020-06  <\/td>\n C128\/C128D <\/td>\n KERNAL version 3           <\/td>\n 16 KB <\/td>\n unreleased<\/strong> <\/td>\n<\/tr>\n
 318023-02  <\/td>\n C128DCR    <\/td>\n C64 ROM + KERNAL version 2 <\/td>\n 32 KB <\/td>\n released   <\/td>\n<\/tr>\n
 318023-03  <\/td>\n C128DCR    <\/td>\n C64 ROM + KERNAL version 3 <\/td>\n 32 KB <\/td>\n unreleased<\/strong> <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Parsing the .LST<\/code> Files<\/h2>\n
In addition to the source trees of the two versions, the archive also contains an .LST<\/code> file for each version. An .LST<\/code> file is generated during assembly and consists of every source line annotated with the current address and the generated object bytes.<\/p>\n
Here is an example line:<\/p>\n
     E000   A2 FF        2367   start   ldx #$ff        ;normal \/reset entry\n<\/code><\/pre>\n