Analyze BASIC Tokens Workflow

Use this skill when the user asks to:

• "analyze this BASIC code"
• "decode basic commands from memory"
• "create side comments for BASIC lines"
• "parse basic pointer address and line number"

1. Determine Memory Range

Identify the starting and ending addresses of the Commodore BASIC sequence from the user's request or cross-references. If unspecified, prompt the user for clarification.

2. Read Memory Buffer

Invoke the r2000_read_region tool to read the requested sequence:

• start_address: The sequence start address (decimal).
• end_address: The sequence end address (decimal).
• view: "hexdump"

3. Process BASIC Lines

Commodore BASIC programs follow a strict structured sequence in memory. Iterate through the sequences byte-by-byte:

Line Anatomy

1. Bytes 0–1: Pointer to the address of the next BASIC line in Little Endian (e.g., 24 04 $\rightarrow$ $0424).
2. Bytes 2–3: BASIC Line number as a 16-bit integer in Little Endian (e.g., 0A 00 $\rightarrow$ 10).
3. Bytes 4–N: The tokenized BASIC command ending with a $00 byte.
4. Termination: If the pointer bytes are $00 $00, the iteration stops.

Keyword Token Table (V2)

Bytes in step 3 with the high-bit set ($80 to $CB) are keyword tokens. Decode them against this table:

(Note: Bytes between $20 and $7F are literal PETSCII text characters like strings, variables, and numbers).

4. Apply Modifications

Formulate a sequence of commands for r2000_batch_execute to apply the modifications for all decoded BASIC lines at once.

For each decoded line:

1. Use r2000_set_data_type on Bytes 0–1 as "address".
2. Use r2000_set_data_type on Bytes 2–3 as "word".
3. Form a complete BASIC line string (e.g., 10 REM LODE RUNNER).
4. Use r2000_set_comment to set the string as a "side" comment at the start of the sequence (Byte 0).

5. Save Project

When completed, invoke r2000_save_project to persist the comments and types.