Level Epsilon Architecture Support Reference Manual

Operator Set
Reference chain evaluation performed by VALC is:
::= {address couple}
::= {operand}
address couple SIRW
IndexedDD
PCW
SIRW SIRW
IndexedDD
PCW
IndexedDD
PCW SIRW
IndexedDD
Reference evaluation is performed by invocation of the common action aFOP. An
operand value is left on the stack as the result of VALC and any non- operand value is
examined as an element of the reference chain. If a PCW must be evaluated, accidental
entry is performed by invoking the common action aACCE. Return from the function
causes VALC to be resumed in restart mode; the operator ignores its code parameter
and consumes a stack argument as the target of the PCW.
LVLC
LVLC is equivalent to VALC, except the parameter is a fixed-fence rather than a variablefence
address couple. LVLC is a four-syllable operator whose appearance in the code
stream is as follows:
Operator :
LVLC lam : delta
format: :
:
4 : 12
VLC0
VLC1
VLC2
VLC3
VLC0, VLC1, VLC2, and VLC3 are equivalent to VALC, except that lambda is specified
directly by the operator code itself. They are three syllable operators whose appearance
in the code stream is:
Operator
VLCx delta
format:
5–54 6878 7530–007