int GPerlVirtualMachine::run(GPerlVirtualMachineCode *codes)
{
static GPerlVirtualMachineCode *top;
GPerlVirtualMachineCode *pc = codes;
Reg reg_[MAX_CALLSTACK_SIZE];
Reg *reg = reg_;
GPerlEnv *callstack = createCallStack();
GPerlObject **argstack = createArgStack();
static char shared_buf[128] = {0};//TODO must be variable buffer
static string outbuf = "";
#include "gen_label.cpp"
DISPATCH_START();
CASE(UNDEF), {
GPERL_UNDEF();
pc++;
BREAK();
});
/*
*****************************************************************************************************************
* codeGenerator:
* child : The ASTNode for which the code has to be generated.
* funInfo : This has the FunctionNode(see astDef.h for details) for the function
* which has the 'child'.
* currLabel : Possible label which can be assigned to the current instruction.
* parentLabel : The label of the parent node in AST.
* This function simply does the post order traversal of a function and generates code for that function.
* In our case it works only for the main function.
*****************************************************************************************************************
*/
void codeGenerator(ASTNode* child,FunctionNode* funInfo,Label* currLabel, int parentLabel){
if(child==NULL){
return;
}
int tempCount = funInfo->width;
int tempLabel = currLabel->labelNum;
InstructionList* funLabel = NULL;
ASTNode* ifChild = NULL;
int ifFlag=0;
TokenName tokenName = child->token->tokenName;
switch(tokenName){
case TK_MAIN: funLabel = createLabel(1,0);
strcpy(funLabel->label,"main");
generate(funLabel);
createCallStack(child);
break;
case TK_ASSIGNOP: generateArithmeticExpression(child,funInfo->funTok,&tempCount);
break;
case TK_IF: currLabel->labelNum += 2;
generateBooleanExpression(child->child,funInfo->funTok,addLabel(1,tempLabel),addLabel(0,tempLabel),currLabel,&tempCount);
generate(createLabel(1,tempLabel));
break;
case TK_ELSE: generate(createInstruction(JMP,-1,-1,parentLabel+1,1,0));
generate(createLabel(0,parentLabel));
break;
case TK_READ: generateScanf(child->child,funInfo);
break;
case TK_WRITE: generatePrintf(child->child,funInfo);
break;
case TK_WHILE: generate(createLabel(1,currLabel->labelNum));
currLabel->labelNum += 2;
generateBooleanExpression(child->child,funInfo->funTok,addLabel(1,tempLabel+1),addLabel(0,tempLabel),currLabel,&tempCount);
generate(createLabel(1,tempLabel+1));
break;
}
if(tokenName==TK_IF)
codeGenerator(child->child,funInfo,currLabel, tempLabel);
else
codeGenerator(child->child,funInfo,currLabel, parentLabel);
switch(tokenName){
case TK_MAIN: generate(createInstruction(ADD,RSP,IMM,0,0,funInfo->width+funInfo->tempCount));
generate(createInstruction(RET,-1,-1,-1,-1,-1));
break;
case TK_WHILE: generate(createInstruction(JMP,-1,-1,tempLabel,1,0));
generate(createLabel(0,tempLabel));
break;
case TK_IF: generate(createLabel(1,tempLabel+1));
ifChild = child->child;
while(ifChild!=NULL){
if(ifChild->token->tokenName==TK_ELSE){
ifFlag = 1;
break;
}
ifChild = ifChild->next;
}
if(!ifFlag)
generate(createLabel(0,tempLabel));
break;
}
codeGenerator(child->next,funInfo,currLabel, parentLabel);
}
