First post, by matze79
this is a thread about Patching Tandy Games to 0E0 Port.
with debug.exe (MS-DOS Command) this can be done really easy, gamma from dosreloaded.de showed me howto make small adjustments to com files.
i patched digipak driver for tandy ex/tx, now its working with Port 0E0h.
Disassemble your Program (nbasm is really good, choose 16bit Mode)
We are looking for OUT C0,AL, lets see what it is in HEX Format
Use MS-DOS Debug:
We get this:
xxxx:0100 E6C0 OUT C0,AL
Now lets search for the opcode in hexformat:
-s 0 ffff e6 C0
Now we get several Hits:
--> 1. 1 Hit at xxxx:05AC
We examine the Position:
We get: "xxxx:05AC E6C0 OUT C0,AL"
Now lets change the position to "out e0,al":
lets check if everything is right:
--> it changed
Lets repeat with all other Positions!
This will work with files up to 64kbyte, note that debug will complain about i can`t save to EXE or HEX Format.. simply rename files should to the trick ( i did only try yet with Digipak Driver TANEXTX.COM which worked very well!)