Disassemble Python Bytecode and Match to CPython Source

Disassembling Python Bytecode

The \`dis\` module prints the opcodes CPython will execute. Pairing \`dis\` output with \`Python/compile.c\` and \`ceval.c\` is how you learn what the compiler actually emitted.

Reading dis Output

Each line shows offset, opcode name, and argument:

• \`LOAD_CONST\`: push a value from the code object's constant tuple
• \`LOAD_FAST\`: read a local by index
• \`CALL\`: invoke the callable on the stack (CPython 3.11+ uses specialized forms)

For example, \`def add(a, b): return a + b\` disassembles to loads of \`a\` and \`b\`, \`BINARY_OP\` or \`BINARY_ADD\`, then \`RETURN_VALUE\`.

Match opcodes to compiler phases:

1. AST from \`compile.c\`
2. Bytecode in \`co_code\`
3. Handlers in \`ceval.c\`

Design Notes

Specialized opcodes in CPython 3.11+ replace generic forms for common patterns. When dis output shows `CACHE` lines, you are looking at the adaptive specialization machinery, not user bytecode.

For This Exercise

This exercise asks you to disassemble sample functions and map opcodes to CPython source concepts. You will document how \`dis\` reveals the stack operations behind familiar Python syntax.

You will use the same mental model here when reading production interpreter source later in the track. Sketch one concrete input on paper, predict the outcome, then confirm with code. That discipline catches logic errors early and makes debugging far faster when you extend the implementation in follow-on tasks.