llvm-6502/lib/Target/Alpha/AlphaInstrFormats.td

//===- AlphaInstrFormats.td - Alpha Instruction Formats ----*- tablegen -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//

//3.3:
//Memory
//Branch
//Operate
//Floating-point
//PALcode

//===----------------------------------------------------------------------===//
// Instruction format superclass
//===----------------------------------------------------------------------===//

class InstAlpha<bits<6> op, dag OL, string asmstr> : Instruction {          // Alpha instruction baseline
  field bits<32> Inst;
  let Namespace = "Alpha";
  let OperandList = OL;
  let AsmString = asmstr;

 
  let Inst{31-26} = op;
}

//3.3.1
class MForm<bits<6> opcode, dag OL, string asmstr> : InstAlpha<opcode, OL, asmstr> {
  bits<5> Ra;
  bits<5> Rb;
  bits<16> disp;

  let Inst{25-21} = Ra;
  let Inst{20-16} = Rb;
  let Inst{15-0} = disp;
}

//3.3.2
let isBranch = 1, isTerminator = 1 in
class BForm<bits<6> opcode, dag OL, string asmstr> : InstAlpha<opcode, OL, asmstr> {
  bits<5> Ra;
  bits<21> disp;

  let Inst{25-21} = Ra;
  let Inst{20-0} = disp;
}

//3.3.3
class OForm<bits<6> opcode, bits<7> fun, dag OL, string asmstr> : InstAlpha<opcode, OL, asmstr> {
  bits<5> Ra;
  bits<5> Rb;
  bits<3> SBZ;
  bits<7> Function = fun;
  bits<5> Rc;

  let Inst{25-21} = Ra;
  let Inst{20-16} = Rb;
  let Inst{15-13} = SBZ;
  let Inst{12} = 0;
  let Inst{11-5} = Function;
  let Inst{4-0} = Rc;
}


class OFormL<bits<6> opcode, bits<7> fun, dag OL, string asmstr> : InstAlpha<opcode, OL, asmstr> {
  bits<5> Ra;
  bits<8> LIT;
  bits<7> Function = fun;
  bits<5> Rc;

  let Inst{25-21} = Ra;
  let Inst{20-13} = LIT;
  let Inst{12} = 1;
  let Inst{11-5} = Function;
  let Inst{4-0} = Rc;
}

//3.3.4
class FPForm<bits<6> opcode, bits<11> fun, dag OL, string asmstr> : InstAlpha<opcode, OL, asmstr> {
  bits<5> Fa;
  bits<5> Fb;
  bits<11> Function = fun;
  bits<5> Fc;

  let Inst{25-21} = Fa;
  let Inst{20-16} = Fb;
  let Inst{15-5} = Function;
  let Inst{4-0} = Fc;
}

//3.3.5
class PALForm<bits<6> opcode, dag OL, string asmstr> : InstAlpha<opcode, OL, asmstr> {
  bits<26> Function;

  let Inst{25-0} = Function;
}


// Pseudo instructions.
class PseudoInstAlpha<dag OL, string nm> : InstAlpha<0, OL, nm>  {
}