--- Declarations:

A memory variables are declared as follows:
        (locality a-mem)
        a-variable-name (initial-value)
        ...


--- Entry:

Instructions are put in I memory.
        (locality i-mem)

The entry point where %proc begins is declared as follows:
        (misc-inst-entry %proc)

The pdl stack contains a fixed number of arguments to the procedure.


--- Code:


#+EXP
#+LAMBDA
#-LAMBDA
A-V-REGION-FREE-POINTER points to a table containing the free pointer for each region.
        ((vma-start-read) add n a-v-region-free-pointer) gets free pointer for region n.
CALL-RETURN when first proc returns, jump immediately to second proc.
        (call-return loc1 loc2)
ILLOP-IF-PAGE-FAULT
MD-START-WRITE
PDL-POP
Q-POINTER strips type and cdr information, leaving only a number.  (unboxes)
        ((r) q-pointer v)
VMA-START-READ starts a lookup in virtual memory; the result will be in md
        ((vma-start-read) op v1 v2) | ((vma-start-read) v)
        (check-page-read) | (illop-if-page-fault)
XFALSE
XTRUE

(call loc)
(call-xct-next loc)
(jump-equal v1 v2 loc)
(jump-not-equal v1 v2 loc)

unboxing:
        ((r) output-selector-mask 25 op v1 v2)
        ((r) dpb m-zero q-all-but-pointer v)

to test a boolean value:
        ((m-tem) dpb m-zero q-all-but-typed-pointer v)  ; zeros out the cdr code
        (op-if-[not-]equal m-tem a-v-nil)