[mips][mips64r6] ll, sc, lld, and scd are re-encoded on MIPS32r6/MIPS64r6.

Summary:
The linked-load, store-conditional operations have been re-encoded such
that have a 9-bit offset instead of the 16-bit offset they have prior to
MIPS32r6/MIPS64r6.

While implementing this, I noticed that the atomic load/store pseudos always
emit a sign extension using sll and sra. I have improved this to use seb/seh
when they are available (MIPS32r2/MIPS64r2 and above).

Depends on D4118

Reviewers: jkolek, zoran.jovanovic, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D4119

llvm-svn: 211018

1 files changed, 26 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
index 7e5fd7e52dc..908166f0a7b 100644
--- a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
+++ b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -272,6 +272,11 @@ static DecodeStatus DecodeFMem(MCInst &Inst, unsigned Insn,
                                uint64_t Address,
                                const void *Decoder);
 
+static DecodeStatus DecodeSpecial3LlSc(MCInst &Inst,
+                                       unsigned Insn,
+                                       uint64_t Address,
+                                       const void *Decoder);
+
 static DecodeStatus DecodeSimm16(MCInst &Inst,
                                  unsigned Insn,
                                  uint64_t Address,
@@ -1068,6 +1073,27 @@ static DecodeStatus DecodeFMem(MCInst &Inst,
   return MCDisassembler::Success;
 }
 
+static DecodeStatus DecodeSpecial3LlSc(MCInst &Inst,
+                                       unsigned Insn,
+                                       uint64_t Address,
+                                       const void *Decoder) {
+  int64_t Offset = SignExtend64<9>((Insn >> 7) & 0x1ff);
+  unsigned Rt = fieldFromInstruction(Insn, 16, 5);
+  unsigned Base = fieldFromInstruction(Insn, 21, 5);
+
+  Rt = getReg(Decoder, Mips::GPR32RegClassID, Rt);
+  Base = getReg(Decoder, Mips::GPR32RegClassID, Base);
+
+  if(Inst.getOpcode() == Mips::SC_R6 || Inst.getOpcode() == Mips::SCD_R6){
+    Inst.addOperand(MCOperand::CreateReg(Rt));
+  }
+
+  Inst.addOperand(MCOperand::CreateReg(Rt));
+  Inst.addOperand(MCOperand::CreateReg(Base));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
 
 static DecodeStatus DecodeHWRegsRegisterClass(MCInst &Inst,
                                               unsigned RegNo,