6502bench

- Introduction
- About Disassembly
- Using SourceGen
  - Moving Around
  - Making Edits
  - Labels & Symbols
  - Editing Data Operands
  - Generating Code
- Digging Deeper
  - String Formatting
  - Local Variables
  - Inline Data
  - Odds & Ends
- Advanced Topics
  - Address Tables
  - Extension Scripts
  - Visualizations
- Suggestions

## Inline Data

Consider the code at address $206B. It's a `JSR` followed by some ASCII text, then a $00 byte, and then what might be code.

...

Double-click on the `JSR` opcode to jump to $20AB to see the function. It pulls the call address off the stack, and uses it as a pointer. When it encounters a zero byte, it breaks out of the loop, pushes the adjusted pointer value back onto the stack, and returns.

This is an example of "inline data", where a function uses the return address to get a pointer to data. The return address is adjusted to point past the inline data before returning (technically, it points at the very last byte of the inline data, because `RTS` jumps to address + 1).

To format the data, we first need to tell SourceGen that there's data in line with the code. Select the line at address $206E, then shift-click the line at address $2077. Use `Actions > Tag Bytes As Inline Data` (`Ctrl+H` `Ctrl+I`).

Unlike code start and end tags, where you only tag the byte where the code starts or stops, for inline data you need to tag every byte.

The data turns to single-byte values, and we now see the code continuing at address $2078. We can format the data as a string by using `Actions > Edit Operand`, setting the Character Encoding to `Low or High ASCII`, and selecting `null-terminated strings`.

That's pretty straightforward, but this could quickly become tedious if there were a lot of these. SourceGen allows you to define scripts to automate common formatting tasks. This is covered in the "Extension Scripts" tutorial.

« Previous Next »