public IEnumerable <string> ToAssembly(string line)
{
var parts = line.Split(' ');
if (parts.Length < 3)
{
throw new InvalidOperationException("Call command must be of the form 'call foo 2'");
}
var functionName = parts[1];
var nArgs = parts[2];
var callCount = callCounter.GetCount(functionName);
var assembly = new []
{
$"// {line}",
$"// push {functionName}$ret.{callCount}",
$"@{functionName}$ret.{callCount}",
"D=A",
"@SP",
"A=M",
"M=D",
"@SP",
"M=M+1",
"// push LCL",
"@LCL",
"D=M",
"@SP",
"A=M",
"M=D",
"@SP",
"M=M+1",
"// push ARG",
"@ARG",
"D=M",
"@SP",
"A=M",
"M=D",
"@SP",
"M=M+1",
"// push THIS",
"@THIS",
"D=M",
"@SP",
"A=M",
"M=D",
"@SP",
"M=M+1",
"// push THAT",
"@THAT",
"D=M",
"@SP",
"A=M",
"M=D",
"@SP",
"M=M+1",
"// ARG = SP-5-nArgs",
"@SP",
"D=M",
"@5",
"D=D-A",
$"@{nArgs}",
"D=D-A",
"@ARG",
"M=D",
"// LCL = SP",
"@SP",
"D=M",
"@LCL",
"M=D",
$"// goto {functionName}",
$"@{functionName}",
"0;JMP",
$"({functionName}$ret.{callCount})",
""
};
callCounter.IncrementCount(functionName);
return(assembly);
}