bool
Buffer::operator != (const Buffer &rhs) const
{
if (rhs.readAvailable() != readAvailable())
return true;
return opCmp(rhs) != 0;
}
bool
Buffer::operator!= (const std::string &string) const
{
if (string.size() != readAvailable())
return true;
return opCmp(string.c_str(), string.size()) != 0;
}
bool
Buffer::operator == (const Buffer &rhs) const
{
if (rhs.readAvailable() != readAvailable())
return false;
return opCmp(rhs) == 0;
}
bool
Buffer::operator!= (const char *string) const
{
size_t length = strlen(string);
if (length != readAvailable())
return true;
return opCmp(string, length) != 0;
}
int allocateRegForOp(Operand* op, FILE* fp){
//在varList中寻找op对应的变量的VarDes
VarDes* var = varList;
while(var!=NULL){
if(opCmp(var->op, op)==0)
break;
var = var->next;
}
//如果op对应的变量第一次被使用 则记录栈中相对于栈底($fp)的位置(偏移量)
int isFirstUsed = FALSE;
if(var == NULL){
isFirstUsed = TRUE;
var = malloc(sizeof(VarDes));
memset(var, 0, sizeof(VarDes));
var->op = op;
var->regNo = -1;
if(var->op->kind == VAR_OP || var->op->kind == TEM_VAR_OP){
offset += 4;
var->offset = offset;
}
if(var->op->kind != CONST_OP)
addVarToList(var);
}
//如果op对应的变量没有被分配寄存器 则为其分配寄存器
if(var->regNo < 0){
int regNo = getReg(fp);
var->regNo = regNo;
regList[regNo].var = var;
if(var->op->kind == CONST_OP||var->op->kind == ADDR_OP||(isFirstUsed==FALSE && var->offset>=0)){
//不是第一次出现的变量
ldVar(var, fp);
}
}
//每次寄存器中的变量被使用 old字段就会置零
regList[var->regNo].old = 0;
return var->regNo;
}