[mips][microMIPS] Implement SWM16 and LWM16 instructions

[zoran.jovanovic]

Rebased.
Error handling changed.
Offset shift fixed.

[sstankovic]

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

792

This method is never called. I think the problem is that you use parseRegisterList for parsing RegList16 operands. At the end of parseRegisterList, operand of k_RegList is created, which means that isRegList() will be called instead of isRegList16().

lib/Target/Mips/MicroMipsInstrInfo.td

215

You probably need RegListAsmOperand here.

[zoran.jovanovic]

Patch rebased and some unnecessary code removed.

[sstankovic]

For the following illegal instructions the error is not reported:

lwm16 $16, 8($sp)
lwm16 $16, $17, 8($sp)
lwm16 $16-$20, 8($sp)

Please include these instructions in the tests, to make sure the error is reported.

lib/Target/Mips/Disassembler/MipsDisassembler.cpp

348

You can put "unsigned Insn" on the previous line - it fits in 80 columns.

1422

Same here.

[zoran.jovanovic]

PredicateMethod added to check whether reglistoperand16 is valid.

[sstankovic]

LGTM, with two changes.

lib/Target/Mips/MicroMipsInstrInfo.td

374

This line is unaligned.

381

Same here.

Closed by commit rL222901 (authored by zjovanovic).

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

   template <unsigned Bits> bool isMemWithSimmOffset() const {
     return isMem() && isConstantMemOff() && isInt<Bits>(getConstantMemOff());
   }
+  template <unsigned Bits> bool isMemWithUimmOffsetSP() const {
+    return isMem() && isConstantMemOff() && isUInt<Bits>(getConstantMemOff())
+      && getMemBase()->isRegIdx() && (getMemBase()->getGPR32Reg() == Mips::SP);
+  }
   bool isInvNum() const { return Kind == k_Immediate; }
   bool isLSAImm() const {
     if (!isConstantImm())

lib/Target/Mips/Disassembler/MipsDisassembler.cpp

                                          uint64_t Address,
                                          const void *Decoder);
 
+static DecodeStatus DecodeRegListOperand16(MCInst &Inst,
+                                           unsigned Insn,
+                                           uint64_t Address,
+                                           const void *Decoder);
+
 namespace llvm {
 extern Target TheMipselTarget, TheMipsTarget, TheMips64Target,
               TheMips64elTarget;

 
   return MCDisassembler::Success;
 }
+
+static DecodeStatus DecodeRegListOperand16(MCInst &Inst,
+                                           unsigned Insn,
+                                           uint64_t Address,
+                                           const void *Decoder) {
+  unsigned Regs[] = {Mips::S0, Mips::S1, Mips::S2, Mips::S3};
+  unsigned RegNum;
+
+  unsigned RegLst = fieldFromInstruction(Insn, 4, 2);
+  // Empty register lists are not allowed.
+  if (RegLst == 0)
+    return MCDisassembler::Fail;
+
+  RegNum = RegLst & 0x3;
+  for (unsigned i = 0; i < RegNum - 1; i++)
+    Inst.addOperand(MCOperand::CreateReg(Regs[i]));
+
+  Inst.addOperand(MCOperand::CreateReg(Mips::RA));
+
+  return MCDisassembler::Success;
+}

lib/Target/Mips/InstPrinter/MipsInstPrinter.cpp

     break;
   case Mips::SWM32_MM:
   case Mips::LWM32_MM:
+  case Mips::SWM16_MM:
+  case Mips::LWM16_MM:
     opNum = MI->getNumOperands() - 2;
     break;
   }

lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.h

   unsigned getMemEncodingMMImm12(const MCInst &MI, unsigned OpNo,
                                  SmallVectorImpl<MCFixup> &Fixups,
                                  const MCSubtargetInfo &STI) const;
+  unsigned getMemEncodingMMImm4sp(const MCInst &MI, unsigned OpNo,
+                                  SmallVectorImpl<MCFixup> &Fixups,
+                                  const MCSubtargetInfo &STI) const;
   unsigned getSizeExtEncoding(const MCInst &MI, unsigned OpNo,
                               SmallVectorImpl<MCFixup> &Fixups,
                               const MCSubtargetInfo &STI) const;

   unsigned getRegisterListOpValue(const MCInst &MI, unsigned OpNo,
                                   SmallVectorImpl<MCFixup> &Fixups,
                                   const MCSubtargetInfo &STI) const;
+
+  unsigned getRegisterListOpValue16(const MCInst &MI, unsigned OpNo,
+                                    SmallVectorImpl<MCFixup> &Fixups,
+                                    const MCSubtargetInfo &STI) const;
 }; // class MipsMCCodeEmitter
 } // namespace llvm.
 

lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp

   return (OffBits & 0x0FFF) | RegBits;
 }
 
+unsigned MipsMCCodeEmitter::
+getMemEncodingMMImm4sp(const MCInst &MI, unsigned OpNo,
+                       SmallVectorImpl<MCFixup> &Fixups,
+                       const MCSubtargetInfo &STI) const {
+  // opNum can be invalid if instruction had reglist as operand
+  // MemOperand is always last operand of instruction (base + offset)
+  switch (MI.getOpcode()) {
+  default:
+    break;
+  case Mips::SWM16_MM:
+  case Mips::LWM16_MM:
+    OpNo = MI.getNumOperands() - 2;
+    break;
+  }
+
+  // Offset is encoded in bits 4-0.
+  assert(MI.getOperand(OpNo).isReg());
+  // Base register is always SP - thus it is not encoded.
+  assert(MI.getOperand(OpNo+1).isImm());
+  unsigned OffBits = getMachineOpValue(MI, MI.getOperand(OpNo+1), Fixups, STI);
+
+  return ((OffBits >> 2) & 0x0F);
+}
+
 unsigned
 MipsMCCodeEmitter::getSizeExtEncoding(const MCInst &MI, unsigned OpNo,
                                       SmallVectorImpl<MCFixup> &Fixups,

   return res;
 }
 
+unsigned
+MipsMCCodeEmitter::getRegisterListOpValue16(const MCInst &MI, unsigned OpNo,
+                                            SmallVectorImpl<MCFixup> &Fixups,
+                                            const MCSubtargetInfo &STI) const {
+  return (MI.getNumOperands() - 4);
+}
+
 #include "MipsGenMCCodeEmitter.inc"

lib/Target/Mips/MicroMipsInstrFormats.td

   let Inst{15-12} = funct;
   let Inst{11-0}  = addr{11-0};
 }
+
+class LWM_FM_MM16<bits<4> funct> : MMArch {
+  bits<2> rt;
+  bits<4> addr;
+
+  bits<16> Inst;
+
+  let Inst{15-10} = 0x11;
+  let Inst{9-6}   = funct;
+  let Inst{5-4}   = rt;
+  let Inst{3-0}   = addr;
+}

lib/Target/Mips/MicroMipsInstrInfo.td

   let OperandType = "OPERAND_MEMORY";
 }
 
+def MipsMemUimm4AsmOperand : AsmOperandClass {
+  let Name = "MemOffsetUimm4";
+  let SuperClasses = [MipsMemAsmOperand];
+  let RenderMethod = "addMemOperands";
+  let ParserMethod = "parseMemOperand";
+  let PredicateMethod = "isMemWithUimmOffsetSP<6>";
+}
+
+def mem_mm_4sp : Operand<i32> {
+  let PrintMethod = "printMemOperand";
+  let MIOperandInfo = (ops GPR32, uimm8);
+  let EncoderMethod = "getMemEncodingMMImm4sp";
+  let ParserMatchClass = MipsMemUimm4AsmOperand;
+  let OperandType = "OPERAND_MEMORY";
+}
+
 def jmptarget_mm : Operand<OtherVT> {
   let EncoderMethod = "getJumpTargetOpValueMM";
 }

   let DecoderMethod = "DecodeRegListOperand";
 }
 
+def reglist16 : Operand<i32> {
+  let EncoderMethod = "getRegisterListOpValue16";
+  let ParserMatchClass = RegListAsmOperand;
+  let PrintMethod = "printRegisterList";
+  let DecoderMethod = "DecodeRegListOperand16";
+}
+
 class StoreMultMM<string opstr,
             InstrItinClass Itin = NoItinerary, ComplexPattern Addr = addr> :
   InstSE<(outs), (ins reglist:$rt, mem_mm_12:$addr),

   let mayLoad = 1;
 }
 
+class StoreMultMM16<string opstr,
+            InstrItinClass Itin = NoItinerary, ComplexPattern Addr = addr> :
+  MicroMipsInst16<(outs), (ins reglist16:$rt, mem_mm_4sp:$addr),
+                  !strconcat(opstr, "\t$rt, $addr"), [], Itin, FrmI> {
+  let mayStore = 1;
+}
+
+class LoadMultMM16<string opstr,
+            InstrItinClass Itin = NoItinerary, ComplexPattern Addr = addr> :
+  MicroMipsInst16<(outs reglist16:$rt), (ins mem_mm_4sp:$addr),
+                  !strconcat(opstr, "\t$rt, $addr"), [], Itin, FrmI> {
+  let mayLoad = 1;
+}
+
 def ADDU16_MM : ArithRMM16<"addu16", GPRMM16Opnd, 1, II_ADDU, add>,
                 ARITH_FM_MM16<0>;
 def SUBU16_MM : ArithRMM16<"subu16", GPRMM16Opnd, 0, II_SUBU, sub>,

   /// Load and Store Instructions - multiple
   def SWM32_MM  : StoreMultMM<"swm32">, LWM_FM_MM<0xd>;
   def LWM32_MM  : LoadMultMM<"lwm32">, LWM_FM_MM<0x5>;
+  def SWM16_MM : StoreMultMM16<"swm16">, LWM_FM_MM16<0x5>;
+  def LWM16_MM : LoadMultMM16<"lwm16">, LWM_FM_MM16<0x4>;
 
   /// Move Conditional
   def MOVZ_I_MM : MMRel, CMov_I_I_FT<"movz", GPR32Opnd, GPR32Opnd,

test/MC/Mips/micromips-invalid.s

   li16  $4, -2 # CHECK: :[[@LINE]]:{{[0-9]+}}: error: immediate operand value out of range
   addiur2 $9, $7, -1 # CHECK: :[[@LINE]]:{{[0-9]+}}: error: invalid operand for instruction
   addiur2 $6, $7, 10 # CHECK: :[[@LINE]]:{{[0-9]+}}: error: immediate operand value out of range
+  lwm16   $5, $6, $ra, 8($sp)    # CHECK: :[[@LINE]]:{{[0-9]+}}: error: $16 or $31 expected
+  lwm16   $16, $19, $ra, 8($sp)  # CHECK: :[[@LINE]]:{{[0-9]+}}: error: consecutive register numbers expected
+  lwm16   $16-$25, $ra, 8($sp)   # CHECK: :[[@LINE]]:{{[0-9]+}}: error: invalid register operand
+  swm16   $5, $6, $ra, 8($sp)    # CHECK: :[[@LINE]]:{{[0-9]+}}: error: $16 or $31 expected
+  swm16   $16, $19, $ra, 8($sp)  # CHECK: :[[@LINE]]:{{[0-9]+}}: error: consecutive register numbers expected
+  swm16   $16-$25, $ra, 8($sp)   # CHECK: :[[@LINE]]:{{[0-9]+}}: error: invalid register operand
   lwm32   $5, $6, 8($4)    # CHECK: :[[@LINE]]:{{[0-9]+}}: error: $16 or $31 expected
   lwm32   $16, $19, 8($4)  # CHECK: :[[@LINE]]:{{[0-9]+}}: error: consecutive register numbers expected
   lwm32   $16-$25, 8($4)   # CHECK: :[[@LINE]]:{{[0-9]+}}: error: invalid register operand

test/MC/Mips/micromips-loadstore-instructions.s

 # CHECK-EL: lwm32  $16, $17, $18, $19, $20, $21, $22, $23, $fp, $ra, 8($4) # encoding: [0x24,0x23,0x08,0x50]
 # CHECK-EL: swm32  $16, $17, 8($4)            # encoding: [0x44,0x20,0x08,0xd0]
 # CHECK-EL: swm32  $16, $17, $18, $19, 8($4)  # encoding: [0x84,0x20,0x08,0xd0]
+# CHECK-EL: lwm16  $16, $17, $ra, 8($sp)      # encoding: [0x12,0x45]
+# CHECK-EL: swm16  $16, $17, $ra, 8($sp)      # encoding: [0x52,0x45]
 #------------------------------------------------------------------------------
 # Big endian
 #------------------------------------------------------------------------------

 # CHECK-EB: lwm32  $16, $17, $18, $19, $20, $21, $22, $23, $fp, $ra, 8($4) # encoding: [0x23,0x24,0x50,0x08]
 # CHECK-EB: swm32  $16, $17, 8($4)           # encoding: [0x20,0x44,0xd0,0x08]
 # CHECK-EB: swm32  $16, $17, $18, $19, 8($4) # encoding: [0x20,0x84,0xd0,0x08]
+# CHECK-EB: lwm16  $16, $17, $ra, 8($sp)     # encoding: [0x45,0x12]
+# CHECK-EB: swm16  $16, $17, $ra, 8($sp)     # encoding: [0x45,0x52]
      lb     $5, 8($4)
      lbu    $6, 8($4)
      lh     $2, 8($4)

      lwm32  $16-$23, $30 - $31, 8($4)
      swm32  $16, $17, 8($4)
      swm32  $16 - $19, 8($4)
+     lwm16  $16, $17, $ra, 8($sp)
+     swm16  $16, $17, $ra, 8($sp)