/// <summary>
/// Searches for J, JAL, and HI16/LO16 pairs. When it finds these and their values will be zeroed out.
/// This is to facilitate searching of function signatures. <para/>
/// This method buffers its input.
/// </summary>
/// <param name="insns"></param>
/// <returns></returns>
public static IReadOnlyList <InstructionWithPc> ZeroRelocatedValues(this IEnumerable <InstructionWithPc> insns)
{
var analyzer = new Analyzer();
var lastInsn = new Dictionary <int, Instruction>();
var input = insns.ToArray();
var haveHi16 = new bool[32];
var hi16Index = new int[32];
Action pendingAction = null;
for (var i = 0; i < input.Length; i++)
{
var insn = input[i].Instruction;
var action = pendingAction;
var insnId = insn.Id;
var analysis = analyzer.Analyze(insn);
var processedId = insn.IsLoadStore ? MipsInstruction.ADDIU : insnId;
switch (processedId)
{
case MipsInstruction.JAL:
//pendingAction = reset;
goto J;
// Fallthrough
case MipsInstruction.J:
J:
insn.Target = 0;
break;
case MipsInstruction.LUI:
haveHi16[insn.GprRt] = true;
hi16Index[insn.GprRt] = i;
break;
// Case for LO16 relos, ADDIU and load/store ops
case MipsInstruction.ADDIU:
if (haveHi16[insn.GprRs])
{
var tmp = input[hi16Index[insn.GprRs]].Instruction;
tmp.Immediate = 0;
input[hi16Index[insn.GprRs]] = new InstructionWithPc(input[hi16Index[insn.GprRs]].Pc, tmp);
insn.Immediate = 0;
}
haveHi16[insn.GprRs] = false;
hi16Index[insn.GprRs] = 0;
break;
default:
if (analysis != null && analysis.DestinationGpr.HasValue)
{
haveHi16[analysis.DestinationGpr.Value] = false;
}
break;
}
input[i] = new InstructionWithPc(input[i].Pc, insn);
action?.Invoke();
}
return(input);
}
void IDiscoveredFunction.AddInstruction(InstructionWithPc iwp) => _instructions.Add(iwp);
