[mips][msa] Fix immediate value of LSA instruction as it was being wrongly encoded.

    
The immediate field should be encoded as "imm - 1" as the CPU always adds one to that field.

llvm-svn: 195004

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
index b890d3a887c..60508a8c4fc 100644
--- a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
+++ b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -246,6 +246,13 @@ static DecodeStatus DecodeSimm16(MCInst &Inst,
                                  uint64_t Address,
                                  const void *Decoder);
 
+// Decode the immediate field of an LSA instruction which
+// is off by one.
+static DecodeStatus DecodeLSAImm(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder);
+
 static DecodeStatus DecodeInsSize(MCInst &Inst,
                                   unsigned Insn,
                                   uint64_t Address,
@@ -785,6 +792,15 @@ static DecodeStatus DecodeSimm16(MCInst &Inst,
   return MCDisassembler::Success;
 }
 
+static DecodeStatus DecodeLSAImm(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder) {
+  // We add one to the immediate field as it was encoded as 'imm - 1'.
+  Inst.addOperand(MCOperand::CreateImm(Insn + 1));
+  return MCDisassembler::Success;
+}
+
 static DecodeStatus DecodeInsSize(MCInst &Inst,
                                   unsigned Insn,
                                   uint64_t Address,