[Pixel]<DragonWare0.1>DragGen>GenStackTest.mesa!1

GenStackTest.mesa

Russ Atkinson (RRA) September 12, 1986 4:56:11 pm PDT

DIRECTORY

DragOpsCross USING [Word],

HandCoding USING [aux10, const1, drDIS, drJDB, drLC3, drLFC, drLIB, drLRn, drRADD, drRJEBJ, drRJGEB, drRJLBJ, drRSUB, drRVADD, drRVSUB, popSrc, pushDst, reg0, reg1, reg2, RegSpec],

HandCodingPseudos USING [GenLabel, GenLabelHere, Halt, Label, MakeLabelGlobal, ProcedureEntry, ProcedureExit, SetLabel, SReg, UseLabel16, UseLabel8B];

GenStackTest: CEDAR PROGRAM

IMPORTS HandCoding, HandCodingPseudos

= BEGIN OPEN HandCoding, HandCodingPseudos;

Word: TYPE = DragOpsCross.Word;

depthReg: RegSpec = HandCoding.aux10;

An unused aux register that keeps track of the frame depth.

GenRecurse: PROC [entry: Label] = {

times: RegSpec = reg0; -- this value is also returned

size: RegSpec = reg1;

current: RegSpec = reg2;

ProcedureEntry[entry, 2];

MakeLabelGlobal["StackTest.Recurse", entry];

drLC3[]; -- init current to 3 (words initially on stack)

{

loop to put extra words on the stack

loopLabel: Label = GenLabelHere[];

drRADD[current, current, const1];

drLRn[current];

drRJLBJ[left: topSrc, right: size, dist: UseLabel8B[loopLabel]];

};

{

if times > 1, then recurse on times-1

fiLabel: Label = GenLabel[];

drRJGEB[left: const1, right: times, dist: UseLabel8B[fiLabel]];

drRSUB[pushDst, times, const1];

drLRn[size];

drLFC[UseLabel16[entry]];

{okLabel: Label = GenLabel[];

drRSUB[pushDst, times, const1];

drRJEBJ[left: topSrc, right: popSrc, dist: UseLabel8B[okLabel]];

Halt[1];

At this point the returned value of times is not what was passed in. This is an indication that the stack management was blown.

SetLabel[okLabel];

drDIS[];

};

SetLabel[fiLabel];

};

ProcedureExit[1];

};

GenEmptyRecurse: PROC [entry: Label] = {

exitLabel: Label = GenLabel[];

ProcedureEntry[entry, 0];

MakeLabelGlobal["StackTest.EmptyRecurse", entry];

drRJGEB[left: const0, right: depthReg, dist: UseLabel8B[exitLabel]];

drRVSUB[depthReg, depthReg, const1];

drLFC[UseLabel16[entry]];

drRVADD[depthReg, depthReg, const1];

SetLabel[exitLabel];

ProcedureExit[0];

};

All: PROC = {

startLabel: Label = GenLabelHere[];

enterRecurse: Label = GenLabel[];

emptyRecurse: Label = GenLabel[];

testLabel: Label = GenLabel[];

maxDepth: NAT ← 32;

MakeLabelGlobal["StackTest.Start", startLabel];

drJDB[UseLabel16[testLabel]];

GenEmptyRecurse[emptyRecurse];

GenRecurse[enterRecurse];

SetLabel[testLabel];

{

Test for empty stack frames being properly handled. This will cause various IFU overflow and underflow traps. The depthReg register governs how deep we go.

okLabel: Label = GenLabel[];

drLIB[maxDepth];

SReg[depthReg];

drLFC[UseLabel16[emptyRecurse]];

drLIB[maxDepth];

drRJEBJ[left: topSrc, right: depthReg, dist: UseLabel8B[okLabel]];

Halt[1];

SetLabel[okLabel];

};

{

Test for small frames being properly handled. This will exercise the IFU stack overflow handler.

okLabel: Label = GenLabel[];

drLIB[maxDepth];

drLIB[5];

drLFC[UseLabel16[enterRecurse]];

drLIB[maxDepth];

drRJEBJ[left: topSrc, right: popSrc, dist: UseLabel8B[okLabel]];

Halt[2];

SetLabel[okLabel];

drDIS[];

};

{

Test for large frames being properly handled. This will exercise the EU stack overflow handler.

okLabel: Label = GenLabel[];

drLIB[maxDepth];

drLIB[33];

drLFC[UseLabel16[enterRecurse]];

drLIB[maxDepth];

drRJEBJ[left: topSrc, right: popSrc, dist: UseLabel8B[okLabel]];

Halt[3];

SetLabel[okLabel];

drDIS[];

};

Halt[0];

};

END.