[Coco] DOS patch programs

[Roger Taylor]

At 02:04 PM 4/4/2009, you wrote:
>Roger Taylor wrote:
>>
>>Also, CoCo 3 users trying to patch their Disk BASIC ROM while it's 
>>in RAM and saving out the image to burn to an EPROM should know 
>>that the ROM won't run right on a CoCo 1 or 2.  The correct way to 
>>patch the Disk BASIC "2.1" ROM is to run an All-RAM routine first 
>>that recopies the original BASIC, ECB, and Disk BASIC ROMs into 
>>RAM, perform the patches, then save the images.  Depending on the 
>>situation and the ROMs in use, this might not work sometimes....
>>
>>A cure I came up with is a new feature in CCASM that lets you write 
>>DOS patch programs that are merged with an existing ROM image file 
>>to create a ready-to-burn ROM.  For example, a typical CoCo 3 DOS 
>>patcher is a LOADM'able file with multiple ORG statements that jump 
>>around the DOS ROM/RAM making changes.  CCASM assembles the LOADM 
>>file then overlays it with a copy of Disk BASIC 1.1.  The resulting 
>>ROM is naturally compatible with all CoCos that can use a disk controller.
>
>That's an interesting feature, but how do you do that? Using the 
>"includebin" directive?
>
>Christian



CCASM has a new -rompatch switch.  It's not public ready yet because 
it uses hardcoded paths to "decb11.rom" and saves out the new ROM as 
"coconet.rom" no matter what.

When it's ready, game paks and other DOS ROMs can be patched or have 
code written/overlayed into a new ROM image.


-- 
Roger Taylor

http://www.wordofthedayonline.com