diff options
Diffstat (limited to 'unprotbas.rst')
| -rw-r--r-- | unprotbas.rst | 57 |
1 files changed, 56 insertions, 1 deletions
diff --git a/unprotbas.rst b/unprotbas.rst index 28ccd8b..752acd7 100644 --- a/unprotbas.rst +++ b/unprotbas.rst @@ -11,7 +11,7 @@ Unprotect LIST-protected Atari 8-bit BASIC programs SYNOPSIS ======== -unprotbas [**-v**] [**-f**] [**-n**] [**-g**] [**-c**] **input-file** **output-file** +unprotbas [**-v**] [**-f**] [**-n**] [**-g**] [**-c**] [**-r** | **-w**] **input-file** **output-file** DESCRIPTION =========== @@ -56,6 +56,17 @@ will be treated as options. memory, but doesn't write the result anywhere. In this mode, there is no **output-file**. +**-w** + Write the variable names to **varnames.txt**, one per line. + This can be edited, and later used with **-r** to set the variable names + to something sensible rather than A, B, C, etc. For an unprotected + program, you can use **-n** to write the existing names rather than + generating new ones. See **VARIABLE NAMES**, below. + +**-r** + Read variable names from **varnames.txt**, and use them instead of + generating the names. See **VARIABLE NAMES**, below. + EXIT STATUS =========== @@ -167,4 +178,48 @@ remove it with the **-g** option. If removing the "garbage" causes the program to fail to run, it wasn't garbage! **unprotbas** doesn't remove extra data by default, to be on the safe side. +VARIABLE NAMES +============== + +If variable name scrambling was used, the original variable names no +longer exist. **unprotbas** will generate them, according to these rules: + + The first 26 numeric variables will be called *A* through *Z*. Further + numeric variables will be *A1* through *A9*, *B1* through *B9*, etc. + + The first 26 string variables will be *A$* to *Z$*, then *A1$* to + *A9$*, *B1$* to *B9$*, etc. + + The first 26 array variables will be *A(* to *Z(*, then *A1(* to + *A9(*, *B1(* to *B9(*, etc. + +To properly reverse-engineer the protected program, it's necessary to assign +meaningful variable names. **unprotbas** isn't smart enough to do this for you, +but it can semi-automate the process. + +First, run **unprotbas** with the **-w** option. This will create a +file called **varnames.txt**, containing the generated variable names. +These are in order, one line per variable name, ending with *$* for strings +and the *(* for arrays. + +Load the unprotected program on the Atari and LIST it (or use **chkbas** to get a +listing), and edit **varnames.txt** in a text editor. + +As you figure out what each variable's purpose is, change its name +in the text file. Don't delete any lines from the file, and don't +add any. Don't get rid of the *$* or *(* at the end of any line. You +may enter the names in lowercase (**unprotbas** will convert them to +uppercase). Remember to follow the rules for BASIC variable names: +only letters and numbers allowed, and the first character must be +a letter. No duplicates of the same type are allowed (you can have +*FOO* and *FOO$*, but not two numerics called *FOO*). + +When you're finished, re-run **unprotbas**, this time with the **-r** +option. The unprotected program will use your variable names, rather +than generating new ones. + +This process can also be used for regular unprotected programs. Use +**-n -w** the first time, to save the existing variable names to +**varnames.txt** rather than generating new ones. + .. include:: manftr.rst |