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/*
* Code formatter project
* CS 4481
*/
package submit.ast;
import submit.MIPSResult;
import submit.RegisterAllocator;
import submit.SymbolTable;
/**
*
* @author edwajohn
*/
public class While extends AbstractNode implements Statement {
private final Expression expression;
private final Statement statement;
public While(Expression expression, Statement statement) {
this.expression = expression;
this.statement = statement;
}
@Override
public void toCminus(StringBuilder builder, String prefix) {
builder.append(prefix).append("while (");
expression.toCminus(builder, prefix);
builder.append(")\n");
if (statement instanceof CompoundStatement) {
statement.toCminus(builder, prefix);
} else {
statement.toCminus(builder, prefix + " ");
}
}
@Override
public MIPSResult toMIPS(StringBuilder code, StringBuilder data,
SymbolTable symbolTable,
RegisterAllocator regAllocator) {
String loopLabel = "while_truthy_" + SymbolTable.nextId();
String finishedLabel = "finished_while_" + SymbolTable.nextId();
code.append(String.format("%s:\n", loopLabel));
MIPSResult expressionTruthiness =
expression.toMIPS(code, data, symbolTable, regAllocator);
code.append(String.format("bne %s $zero %s\n",
expressionTruthiness.getRegister(),
finishedLabel));
MIPSResult inside = statement.toMIPS(code, data, symbolTable, regAllocator);
regAllocator.clear(inside.getRegister());
code.append(String.format("j %s\n", loopLabel))
.append(String.format("%s:\n", finishedLabel));
return MIPSResult.createVoidResult();
}
}
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