NationalSecurityAgency/ghidra · warning · IllegalArgumentException

Error parsing register=value string {part}

Error message

Error parsing register=value string {part}

What it means

Thrown by FunctionStartRFParams.setRegistersAndValues(csv) when a comma-separated part does not split into exactly two segments on '='. The expected form is 'creg1=x,creg2=y'; a part with zero, or 2+, equals signs fails the regValPair.length != 2 check. Partial state is cleared before throwing.

Source

Thrown at Ghidra/Extensions/MachineLearning/src/main/java/ghidra/machinelearning/functionfinding/FunctionStartRFParams.java:193

	}

	/**
	 * Parses register,value pairs if the form creg1=x,creg2=from csv and stores them.  Any 
	 * existing register,value pairs are discarded.
	 * 
	 * @param csv the list to parse
	 * @throws IllegalArgumentException if there are any parsing errors
	 */
	public void setRegistersAndValues(String csv) {
		contextRegisterNames = new ArrayList<>();
		contextRegisterVals = new ArrayList<>();
		String[] parts = csv.split(",");
		for (String part : parts) {
			String[] regValPair = part.split("=");
			if (regValPair.length != 2) {
				contextRegisterNames.clear();
				contextRegisterVals.clear();
				throw new IllegalArgumentException("Error parsing register=value string " + part);
			}
			String regName = regValPair[0].trim();
			if (trainingSource.getRegister(regName) == null) {
				contextRegisterNames.clear();
				contextRegisterVals.clear();
				throw new IllegalArgumentException(
					"Register " + regName + " not found for program " + trainingSource.getName());
			}
			contextRegisterNames.add(regName);
			BigInteger bigInt = new BigInteger(regValPair[1].trim());
			contextRegisterVals.add(bigInt);
		}
	}

	/**
	 * Parses a CSV into a sorted list of distinct integer values (duplicates are ignored).  Returns
	 * an empty list of a parse error is encountered.
	 * @param csv csv string to parse

View on GitHub (pinned to d5f144c24d)

Solutions

1. Format each element as <register>=<value>, e.g. 'cs=0x33,ds=0x2b'.
2. Split on ',' first, then verify each element contains exactly one '=' before calling setRegistersAndValues.
3. Strip stray commas/whitespace; ensure the value is a valid BigInteger literal (hex 0x.. or decimal).

Example fix

// before
params.setRegistersAndValues("cs:0x33, ds=0x2b"); // ':' instead of '='

// after
params.setRegistersAndValues("cs=0x33,ds=0x2b");

public static boolean isValidRegValCsv(String csv) {
    if (csv == null || csv.trim().isEmpty()) return true; // empty ok if optional
    for (String part : csv.split(",")) {
        String[] kv = part.split("=", -1);
        if (kv.length != 2 || kv[0].trim().isEmpty() || kv[1].trim().isEmpty())
            return false;
    }
    return true;
}

null

try {
    params.setRegistersAndValues(csv);
} catch (IllegalArgumentException e) {
    if (e.getMessage().startsWith("Error parsing register=value string")) {
        // re-prompt user with the correct <reg>=<val> format
    } else throw e;
}

When it happens

Trigger: setRegistersAndValues("eax,ebx=1") (missing '='), or "a==b" (extra '='), or a stray token like "," or whitespace-only segment; any malformed register=value CSV element.

Common situations: User typing context-register constraints in the Function Finder params dialog; a config string copy-pasted from a source that used a different separator (':' or space); trailing comma producing an empty segment.

Related errors

• Entry cannot be blank
• String must not begin or end with a comma
• Invalid element {part} - must be non-negative
• Register {regName} not found for program {programName}
• Maximum size of test sets must be positive!

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/70192862752f2767. Report an issue: GitHub.