public List <Instruction> CodeGen()
{
var code = new List <Instruction>();
if (source.IsConstant())
{
code.AddRange(target.PutFromInt(source.Evaluate()));
}
else
{
var src = source.AsDirectField();
if (src == null)
{
var tgt = target.AsDirectField();
if (tgt == null)
{
var scratch = FieldSRef.ScratchInt();
code.AddRange(source.FetchToField(scratch));
code.AddRange(target.PutFromField(scratch));
}
else
{
code.AddRange(source.FetchToField(tgt));
}
}
else
{
code.AddRange(target.PutFromField(src));
}
}
return(code);
}
public List <Instruction> CodeGen(int truejump, int falsejump)
{
var b = new List <Instruction>();
var f1 = S1.AsDirectField() ?? (S1.IsConstant() ? FieldSRef.Imm1() : null);
if (f1 == null)
{
f1 = FieldSRef.ScratchInt();
b.AddRange(S1.FetchToField(f1));
}
var f2 = S2.AsDirectField() ?? (S2.IsConstant() ? FieldSRef.Imm2() : null);
if (f2 == null)
{
f2 = FieldSRef.ScratchInt();
b.AddRange(S2.FetchToField(f2));
}
b.Add(new Instruction
{
opcode = Opcode.Branch,
op1 = f1,
imm1 = S1.IsConstant() ? new IntSExpr(S1.Evaluate()) : null,
op2 = f2,
imm2 = S2.IsConstant() ? new IntSExpr(S2.Evaluate()) : null,
rjmpeq = this.Op.HasFlag(CompSpec.Equal) ? truejump : falsejump,
rjmplt = this.Op.HasFlag(CompSpec.Less) ? truejump : falsejump,
rjmpgt = this.Op.HasFlag(CompSpec.Greater) ? truejump : falsejump,
});
return(b);
}
public List <Instruction> PutFromReg(RegVRef src)
{
var code = new List <Instruction>();
FieldSRef addr = this.addr as FieldSRef;
if (addr == null)
{
if (this.addr.IsConstant())
{
addr = FieldSRef.Imm1();
}
else
{
addr = FieldSRef.ScratchInt();
code.AddRange(this.addr.FetchToField(addr));
}
}
code.Add(new Instruction
{
opcode = Opcode.MemWrite,
op1 = addr,
op2 = src,
imm1 = this.addr.IsConstant() ? this.addr : null,
});
return(code);
}
public List <Instruction> FetchToReg(RegVRef dest)
{
var code = new List <Instruction>();
FieldSRef addr = this.addr.AsDirectField();
if (addr == null)
{
if (this.addr.IsConstant())
{
addr = FieldSRef.Imm1();
}
else
{
addr = FieldSRef.ScratchInt();
code.AddRange(this.addr.FetchToField(addr));
}
}
code.Add(new Instruction
{
opcode = Opcode.MemRead,
op1 = addr,
dest = dest,
imm1 = this.addr.IsConstant() ? this.addr : null,
idx = this.addr.frame(),
});
return(code);
}
public List <Instruction> CodeGen(int truejump, int falsejump)
{
if (Op == CompSpec.Equal)
{
var b = new List <Instruction>();
b.AddRange(V1.FetchToReg(RegVRef.rScratchTab));
var r2 = V2.AsReg();
if (r2 == null)
{
// if V2 isn't already a register, borrow rScratchInts temporarily to fetch it
r2 = RegVRef.rScratchInts;
b.Add(new Push(RegVRef.rScratchInts));
b.AddRange(V2.FetchToReg(r2));
}
b.Add(new Instruction
{
opcode = Opcode.EachMulV,
acc = true,
dest = RegVRef.rScratchTab,
op1 = r2,
op2 = FieldSRef.Imm2(),
imm2 = new IntSExpr(-1),
});
// restore rScratchInts if needed
if (r2 == RegVRef.rScratchInts)
{
b.Add(new Pop(RegVRef.rScratchInts));
}
var flag = FieldSRef.ScratchInt();
// ensure flag is clear, in case this branch is used in a loop and is coming around again to reuse it
b.Add(new Clear(flag));
// set flag if every=0
b.Add(new Instruction
{
opcode = Opcode.EveryEqS2S1,
op1 = RegVRef.rScratchTab,
dest = flag,
acc = true,
});
b.Add(new Instruction
{
opcode = Opcode.Branch,
op1 = flag,
rjmpeq = falsejump,
rjmplt = falsejump, // lt shouldn't happen at all, but...
rjmpgt = truejump,
});
return(b);
}
else
{
throw new NotImplementedException();
}
}
public List <Instruction> FetchToField(FieldSRef dest)
{
var code = new List <Instruction>();
var f1 = S1.AsDirectField();
if (f1 == null)
{
if (S1.IsConstant())
{
f1 = FieldSRef.Imm1();
}
else
{
f1 = FieldSRef.ScratchInt();
code.AddRange(S1.FetchToField(f1));
}
}
var f2 = S2.AsDirectField();
if (f2 == null)
{
if (S2.IsConstant())
{
f2 = FieldSRef.Imm2();
}
else
{
f2 = FieldSRef.ScratchInt();
code.AddRange(S2.FetchToField(f2));
}
}
Opcode op;
switch (Op)
{
case ArithSpec.Add:
op = Opcode.Add;
break;
case ArithSpec.Subtract:
op = Opcode.Sub;
break;
case ArithSpec.Multiply:
op = Opcode.Mul;
break;
case ArithSpec.Divide:
op = Opcode.Div;
break;
default:
throw new InvalidOperationException();
}
var tmp = FieldSRef.ScratchInt();
code.Add(new Instruction
{
opcode = op,
op1 = f1,
imm1 = S1.IsConstant() ? S1 : null,
op2 = f2,
imm2 = S2.IsConstant() ? S2 : null,
dest = tmp,
acc = true
});
//TODO: optimize this one day?
code.AddRange(dest.PutFromField(tmp));
return(code);
}