private static IEnumerable <string> GenerateEqGtLt(Idgen idgen, string lbl, string kjmp)
{
yield return("(" + lbl + ")");
yield return("@R14"); //a = &sp
yield return("M=D");
yield return("@SP"); //a = &sp
yield return("A=M-1"); //a = sp - 1
yield return("D=M"); //d = sp[1]
yield return("A=A-1"); //a = sp - 2
yield return("D=M-D");
var idTrue = idgen.Id();
var idAfter = idgen.Id();
yield return("@" + idTrue);
yield return("D;" + kjmp);
yield return("@" + idAfter);
yield return("D=0;JEQ");
yield return("(" + idTrue + ")");
yield return("D=-1");
yield return("(" + idAfter + ")");
yield return("@SP"); //a = &sp
yield return("M=M-1"); //sp--
yield return("A=M-1"); //a = sp-1
yield return("M=D"); //sp[-1] = d
yield return("@R14");
yield return("A=M");
yield return("D;JMP");
}
private IEnumerable <string> ProcessEqGtLt(Vmcmd vmcmd, Idgen idgen, string stFunc)
{
var idAfter = idgen.Id();
yield return("@" + idAfter);
yield return("D=A");
switch (vmcmd.Kcmd)
{
case Kcmd.Eq:
yield return("@" + lblEq);
break;
case Kcmd.Gt:
yield return("@" + lblGt);
break;
case Kcmd.Lt:
yield return("@" + lblLt);
break;
}
yield return("D;JMP");
yield return("(" + idAfter + ")");
}
private IEnumerable <string> ProcessCall(Vmcmd vmcmd, Idgen idgen, string stFunc)
{
var lblNext = idgen.Id("after_call");
yield return("//r14: hány argumentum van a veremben");
yield return("//r15: hova kell ugrani");
yield return("//D: hova kell visszatérni");
if (vmcmd.I == 0)
{
yield return("@R14");
yield return("M=0");
}
else if (vmcmd.I == 1)
{
yield return("@R14");
yield return("M=1");
}
else
{
yield return("@" + vmcmd.I);
yield return("D=A");
yield return("@R14");
yield return("M=D");
}
yield return("@" + idgen.Fun(vmcmd.StFn));
yield return("D=A");
yield return("@R15");
yield return("M=D");
yield return("@" + lblNext);
yield return("D=A");
yield return("@" + lblFunCall);
yield return("D;JMP");
yield return("(" + lblNext + ")");
}
private IEnumerable <string> Bootstrap(Idgen idgen)
{
lblFunCall = idgen.Id("funcall");
lblReturn = idgen.Id("return");
lblEq = idgen.Id("eq");
lblGt = idgen.Id("gt");
lblLt = idgen.Id("lt");
var lblEnd = idgen.Id("end");
yield return("//SP=256");
yield return("@256");
yield return("D=A");
yield return("@0");
yield return("M=D");
idgen.filn = "Sys.vm";
foreach (var st in ProcessCall(new Vmcmd(Kcmd.Call, Ksegment.Nil, 0, "Sys.init"), idgen, null))
{
yield return(st);
}
idgen.filn = null;
yield return("(" + lblEnd + ")");
yield return("@" + lblEnd);
yield return("0;JMP");
foreach (var st in GenerateEqGtLt(idgen, lblEq, "JEQ"))
{
yield return(st);
}
foreach (var st in GenerateEqGtLt(idgen, lblGt, "JGT"))
{
yield return(st);
}
foreach (var st in GenerateEqGtLt(idgen, lblLt, "JLT"))
{
yield return(st);
}
foreach (var st in GenerateFunCall())
{
yield return(st);
}
foreach (var st in GenerateReturn())
{
yield return(st);
}
}