[mips][microMIPS] Implement LWSP and SWSP instructions

Differential Revision: http://reviews.llvm.org/D6416

llvm-svn: 224771
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
index 689248b..223a95a 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -678,6 +678,20 @@
 }
 
 unsigned MipsMCCodeEmitter::
+getMemEncodingMMSPImm5Lsl2(const MCInst &MI, unsigned OpNo,
+                           SmallVectorImpl<MCFixup> &Fixups,
+                           const MCSubtargetInfo &STI) const {
+  // Register is encoded in bits 9-5, offset is encoded in bits 4-0.
+  assert(MI.getOperand(OpNo).isReg() &&
+         MI.getOperand(OpNo).getReg() == Mips::SP &&
+         "Unexpected base register!");
+  unsigned OffBits = getMachineOpValue(MI, MI.getOperand(OpNo+1),
+                                       Fixups, STI) >> 2;
+
+  return OffBits & 0x1F;
+}
+
+unsigned MipsMCCodeEmitter::
 getMemEncodingMMImm12(const MCInst &MI, unsigned OpNo,
                       SmallVectorImpl<MCFixup> &Fixups,
                       const MCSubtargetInfo &STI) const {