[Sparc] Add support for decoding 'swap' instruction.

llvm-svn: 203424

1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/lib/Target/Sparc/Disassembler/SparcDisassembler.cpp b/llvm/lib/Target/Sparc/Disassembler/SparcDisassembler.cpp
index df2d3798a24..5cd99d6bfe0 100644
--- a/llvm/lib/Target/Sparc/Disassembler/SparcDisassembler.cpp
+++ b/llvm/lib/Target/Sparc/Disassembler/SparcDisassembler.cpp
@@ -211,6 +211,8 @@ static DecodeStatus DecodeJMPL(MCInst &Inst, unsigned insn, uint64_t Address,
                                const void *Decoder);
 static DecodeStatus DecodeReturn(MCInst &MI, unsigned insn, uint64_t Address,
                                  const void *Decoder);
+static DecodeStatus DecodeSWAP(MCInst &Inst, unsigned insn, uint64_t Address,
+                               const void *Decoder);
 
 #include "SparcGenDisassemblerTables.inc"
 
@@ -445,3 +447,37 @@ static DecodeStatus DecodeReturn(MCInst &MI, unsigned insn, uint64_t Address,
   }
   return MCDisassembler::Success;
 }
+
+static DecodeStatus DecodeSWAP(MCInst &MI, unsigned insn, uint64_t Address,
+                               const void *Decoder) {
+
+  unsigned rd = fieldFromInstruction(insn, 25, 5);
+  unsigned rs1 = fieldFromInstruction(insn, 14, 5);
+  unsigned isImm = fieldFromInstruction(insn, 13, 1);
+  unsigned rs2 = 0;
+  unsigned simm13 = 0;
+  if (isImm)
+    simm13 = SignExtend32<13>(fieldFromInstruction(insn, 0, 13));
+  else
+    rs2 = fieldFromInstruction(insn, 0, 5);
+
+  // Decode RD.
+  DecodeStatus status = DecodeIntRegsRegisterClass(MI, rd, Address, Decoder);
+  if (status != MCDisassembler::Success)
+    return status;
+
+  // Decode RS1.
+  status = DecodeIntRegsRegisterClass(MI, rs1, Address, Decoder);
+  if (status != MCDisassembler::Success)
+    return status;
+
+  // Decode RS1 | SIMM13.
+  if (isImm)
+    MI.addOperand(MCOperand::CreateImm(simm13));
+  else {
+    status = DecodeIntRegsRegisterClass(MI, rs2, Address, Decoder);
+    if (status != MCDisassembler::Success)
+      return status;
+  }
+  return MCDisassembler::Success;
+}