public List <Instruction> CodeGen()
{
var b = new List <Instruction>();
//int args or null in r8
if (args.ints.Count > 0)
{
for (int i = 0; i < args.ints.Count; i++)
{
b.AddRange(new SAssign
{
source = new ArithSExpr(args.ints[i], ArithSpec.Add, IntSExpr.Zero),
target = FieldSRef.VarField(RegVRef.rScratchInts, "signal-" + (i + 1)),
}.CodeGen());
}
}
else
{
b.AddRange(new VAssign
{
source = RegVRef.rNull,
target = RegVRef.rScratchInts,
}.CodeGen());
}
//table arg or null in r7
b.AddRange(new VAssign
{
source = args.vars.Count > 0? args.vars[1] : RegVRef.rNull,
target = RegVRef.rVarArgs,
}.CodeGen());
//TODO: table args 2-n
//jump to function, with return in r8.0
b.Add(new Jump
{
target = new AddrSExpr(name),
callsite = FieldSRef.CallSite,
frame = PointerIndex.ProgConst,
});
// return values are in r7/r8 for use by following code
//capture returned values
//if (sreturn != null) b.AddRange(new SAssign { source = FieldSRef.SReturn, target = sreturn, }.CodeGen());
//if (vreturn != null) b.AddRange(new VAssign { source = RegVRef.rVarArgs, target = (VRef)vreturn ?? RegVRef.rNull, }.CodeGen());
return(b);
}
public List <Instruction> BuildFunction()
{
var b = new List <Instruction>();
// save call site (in r8.signal-0)
b.Add(new Push(RegVRef.rScratchInts));
if (localints.Count > 0)
{
// save parent localints
b.Add(new Push(RegVRef.rLocalInts("parent")));
}
// push regs as needed
foreach (var sym in locals.Where(s => s.type == SymbolType.Register))
{
if (sym.fixedAddr.HasValue)
{
b.Add(new Push(new RegVRef(sym.fixedAddr.Value)));
}
}
// wind stack down for locals if needed
if (framesize > 0)
{
b.Add(new Instruction
{
opcode = Opcode.Add,
op1 = FieldSRef.Imm1(),
imm1 = new IntSExpr(-framesize),
acc = true,
dest = FieldSRef.Pointer(PointerIndex.CallStack)
});
}
// copy params if named
//int args or null in r8
var intparas = locals.Where(sym => sym.type == SymbolType.Parameter && sym.datatype == "int").ToList();
if (intparas.Count() > 0)
{
for (int i = 0; i < intparas.Count(); i++)
{
b.Add(new Instruction
{
opcode = Opcode.Add,
op1 = FieldSRef.IntArg(name, intparas[i].name),
dest = FieldSRef.LocalInt(name, intparas[i].name),
acc = i != 0,
});
}
}
FieldSRef.ResetScratchInts();
b.AddRange(RegVRef.rScratchInts.PutFromReg(RegVRef.rNull));
// body
b.AddRange(body.CodeGen());
// convert rjmp __return => rjmp <integer> to here.
for (int i = 0; i < b.Count; i++)
{
var inst = b[i];
if ((inst.imm1 as AddrSExpr)?.symbol == "__return")
{
inst.imm1 = new IntSExpr(b.Count - i);
}
if ((inst.imm2 as AddrSExpr)?.symbol == "__return")
{
inst.imm2 = new IntSExpr(b.Count - i);
}
b[i] = inst;
}
// wind stack back up for locals if needed
if (framesize > 0)
{
b.Add(new Instruction
{
opcode = Opcode.Add,
op1 = FieldSRef.Imm1(),
imm1 = new IntSExpr(framesize),
acc = true,
dest = FieldSRef.Pointer(PointerIndex.CallStack)
});
}
// restore registers
foreach (var sym in locals.Where(s => s.type == SymbolType.Register).Reverse())
{
if (sym.fixedAddr.HasValue)
{
b.Add(new Pop(new RegVRef(sym.fixedAddr.Value)));
}
}
if (localints.Count > 0)
{
// restore parent localints
b.Add(new Pop(RegVRef.rLocalInts("parent")));
}
// get return site
b.Add(new Exchange(RegVRef.rScratchTab));
b.Add(new Instruction
{
opcode = Opcode.Sub,
op1 = FieldSRef.VarField(RegVRef.rScratchTab, "signal-0"),
op2 = FieldSRef.CallSite,
dest = FieldSRef.CallSite,
acc = true
});
b.Add(new Pop(RegVRef.rScratchTab));
// jump to return site
b.Add(new Jump {
target = FieldSRef.CallSite
});
return(b);
}