How to use VICE to patch the BASIC ROM? (was: Fun with CBM arithmetics)

[MrSterlingBS]

Dear Mike,

Please excuse my late request in this post.
But you know I'm new to the forum and have 1000 questions.

Unfortunately the patch doesn't work on my system (I use VICE 3.7 because I don't have an original VC-20 anymore)
I get the error "BAD SOURCE FILE!"
I load the BASIC-PATCH with ,8






Best regards
Sven

[Mike]

Unfortunately the patch doesn't work on my system (I use VICE 3.7 because I don't have an original VC-20 anymore)
I get the error "BAD SOURCE FILE!"
I load the BASIC-PATCH with ,8

You need to provide a dump of the BASIC ROM without load address on the same disk (as SEQ file!) or in the same PC directory (in VICE, with True Drive Emulation off) as the patch program, named "basic". This then results in the patched file "basic-p", which is suitable to be burned on EPROM or which can serve as replacement ROM file for VICE. VICE contains a copy of the file "basic" in the VIC-20 sub-directory.

In Forum64, I posted a more detailed how-to for the equivalent process of patching the C64 BASIC ROM, look here: link.

Note: I do not (and hopefully others also do not) provide an already patched "basic-p" file. There is still an active defendant of the copyright on the CBM ROMs (Cloanto), and I don't want to step on their shoes.

[MrSterlingBS]

Hello,

its me again.

I followed your instructions on the FORUM64 and the basic.p file was created into the directory.
At the first try i get a 6.7kb file, after the second i get a 8kb file ???

What do you mean with

You need to provide a dump of the BASIC ROM without load address on the same disk (as SEQ file!)

How can i create a BASIC ROM without load address? And what is a SEQ file?
The new BASIC-p ROM must be renamed as BASIC-p.bin ?

BR
Sven

[Mike]

Please follow the instructions exactly as in the Forum64 post I linked to, with all relevant files contained in a PC directory!

You find the file "basic" in the VIC-20 directory of the VICE distribution. Use the VIC-20 relevant version of patch.prg, linked to in this post.

Do not rename the files in any way. No change between lower and upper case. No addition or removal of "." file name extensions.

The SEQ file type is only relevant with CBM DOS media (i.e. real disks or disk images - which we do not use for the current problem at hand). It signals sequential data files which - unlike files of the PRG file type, and per convention(!) - do not use the first two bytes of the file as load address. Instead, the first two bytes are already data.

[MrSterlingBS]

Hi Mike,

thank you, now it works.
I think the problem was to rename the basic-p file to basic-p.bin.

BR
Sven

[Mike]

Neither the file "basic" nor the newly created file "basic-p" are supposed to have a *.bin file name extension! Just read the first lines of the patch program:

Code: Select all

10 OPEN2,8,2,"BASIC,S,R"
11 OPEN3,8,3,"BASIC-P,S,W"
[...]

VICE imposes its own ideas handling conversion between ASCII and PETSCII, leading to lower-case file names on the PC side, which however still appear in upper case on the VIC side. But anyway, the files have their names as given in the OPEN statements. No extra ".BIN".

If one of your tools (namely, DirMaster) changes file names or extensions upon will, DITCH IT! Most of your recent issues you had can be traced to that tool.