Thumb2 assembly parsing and encoding for LDREX/LDREXB/LDREXD/LDREXH.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139381 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index afab484a17..b994d0fa75 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -756,6 +756,14 @@ public:
     int64_t Val = Mem.OffsetImm->getValue();
     return Val >= -1020 && Val <= 1020 && (Val & 3) == 0;
   }
+  bool isMemImm0_1020s4Offset() const {
+    if (Kind != Memory || Mem.OffsetRegNum != 0)
+      return false;
+    // Immediate offset a multiple of 4 in range [0, 1020].
+    if (!Mem.OffsetImm) return true;
+    int64_t Val = Mem.OffsetImm->getValue();
+    return Val >= 0 && Val <= 1020 && (Val & 3) == 0;
+  }
   bool isMemImm8Offset() const {
     if (Kind != Memory || Mem.OffsetRegNum != 0)
       return false;
@@ -1146,6 +1154,14 @@ public:
     Inst.addOperand(MCOperand::CreateImm(Val));
   }
 
+  void addMemImm0_1020s4OffsetOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 2 && "Invalid number of operands!");
+    // The lower two bits are always zero and as such are not encoded.
+    int32_t Val = Mem.OffsetImm ? Mem.OffsetImm->getValue() / 4 : 0;
+    Inst.addOperand(MCOperand::CreateReg(Mem.BaseRegNum));
+    Inst.addOperand(MCOperand::CreateImm(Val));
+  }
+
   void addMemImm8OffsetOperands(MCInst &Inst, unsigned N) const {
     assert(N == 2 && "Invalid number of operands!");
     int64_t Val = Mem.OffsetImm ? Mem.OffsetImm->getValue() : 0;