-- Stack.mesa -- last edited by Sweet, February 27, 1980 3:26 PM -- last edited by Satterthwaite, November 2, 1982 3:53 pm DIRECTORY Alloc: TYPE USING [Notifier], CodeDefs: TYPE USING [Byte, StackIndex, StackLocRec, StackPos, TempAddr, VarComponent], Symbols: TYPE USING [ContextLevel, lZ]; Stack: DEFINITIONS = { OPEN CodeDefs; -- Interface Items StackModelingError: SIGNAL; Above: PROC [s: StackIndex, count: CARDINAL_1, nullOk: BOOL_FALSE] RETURNS [StackIndex]; -- the index of the word "count" above that at "s" Also: PROC [ n: CARDINAL_1, inLink: BOOL_FALSE, tOffset: TempAddr, tLevel: Symbols.ContextLevel_Symbols.lZ]; -- record that the top "n" words on the stack are also in temps -- starting at "tOffset", at lexical level "tLevel" -- requires that top "n" words are already onStack Check: PROC [b: Byte]; -- if stack in "On", assure that operands are loaded, reflect changes -- due to execution of instruction byte "b", check for overflow Clear: PROC; -- pop off all remaining words Decr: PROC [count: CARDINAL_1]; -- remove the "count" top words from the stack model DeleteToMark: PROC; -- ResetToMark, UnMark Depth: PROC RETURNS [d: StackPos]; -- number of words actually on stack Dump: PROC; -- empty the stack into temporaries Dup: PROC [load: BOOL_FALSE]; -- duplicate the top element on the stack -- if "load", load if top is in temp Exchange: PROC; -- exchange the top two elements on the stack Forget: PROC [s: StackIndex, count: CARDINAL_1]; -- remove "count" words beginning at "a" from the stack model Incr: PROC [count: CARDINAL_1]; -- add "count" words to the stack model Init: PROC; KeepOnly: PROC [s: StackIndex, count: CARDINAL]; -- pop off anything above the "count" words at "s" Load: PROC [s: StackIndex, count: CARDINAL_1]; -- put the "count" words beginning at "s" on top Loc: PROC [s: StackIndex, count: CARDINAL_1] RETURNS [StackLocRec]; -- where are the "count" words beginning at "s" Mark: PROC; -- insert a mark, also a label for dumping previous contents MoveToTemp: PROC [firstIndex: StackIndex, count: CARDINAL_1] RETURNS [VarComponent]; -- store "count" words from stack into contiguous temps New: PROC RETURNS [old: StackIndex]; Off: PROC; On: PROC; Pop: PROC [count: CARDINAL_1]; -- pop off the top "count" words (unless they are already in temps) Prefix: PROC [sti: StackIndex]; -- link saved away stack item on front of model Require: PROC [count: StackPos]; -- empty all but the top "count" words into temporaries -- the top "count" words may also be dumped if necessary Reset: PROC; ResetToMark: PROC; -- load items back to the first mark, remove from model Restore: PROC [s: StackIndex]; RoomFor: PROC [n: CARDINAL] RETURNS [BOOL]; -- will the stack overflow if n more words are loaded TempStore: PROC [count: CARDINAL_1] RETURNS [VarComponent]; -- store the top "count" words into a temp Top: PROC [count: CARDINAL_1] RETURNS [StackIndex]; -- the index of the word "count" down from the top UnMark: PROC; -- remove the topmost mark VDepth: PUBLIC PROC RETURNS [StackPos]; -- the current depth of the virtual stack VDepthOf: PROC [s: StackIndex] RETURNS [d: StackPos]; -- the virtual depth of the word at "s" StackImplNotify: Alloc.Notifier; }. Ê˜J˜²—…— 4 W