legacy - open interface for code transformation
gc - move some codes around
some warnings about extract-register-names
legacy - not working not sure why
legacy - hacky but working
legacy - solve problems about extract-reg-names
legacy - wrong usage of extract-reg-names
legacy - bug fix on lower
need to remove all initialize-stack from lower
gc - remove "initialize-stack"
gc - decouple simu, broken legacy
gc - lib decoupled
gc - a little more doc
5.3.2 - something about GC

something not mentioned in the book
5.3.2 - special care with pc and flag
5.3.2 - jump to and jump back
5.2.3 - a little more
5.3.2 - address "out of memory"
add "debug-print" primitive
gc - done