From 7eab97f260ba0f56d1d4a82f3a4eb2c979452011 Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Thu, 11 Nov 2010 16:55:29 +0000
Subject: [PATCH] Encoding for ARM LDRSH_POST.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118794 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMCodeEmitter.cpp   |  2 ++
 lib/Target/ARM/ARMInstrFormats.td   | 20 +++++++++++++-------
 lib/Target/ARM/ARMInstrInfo.td      |  1 +
 lib/Target/ARM/ARMMCCodeEmitter.cpp | 23 +++++++++++++++++++++++
 4 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/lib/Target/ARM/ARMCodeEmitter.cpp b/lib/Target/ARM/ARMCodeEmitter.cpp
index 49d8ade4fc6..4aa73851a04 100644
--- a/lib/Target/ARM/ARMCodeEmitter.cpp
+++ b/lib/Target/ARM/ARMCodeEmitter.cpp
@@ -202,6 +202,8 @@ namespace {
       Binary |= (Reg << 13);
       return Binary;
     }
+    uint32_t getAddrMode3OffsetOpValue(const MachineInstr &MI, unsigned OpIdx)
+      const { return 0;}
     uint32_t getAddrMode3OpValue(const MachineInstr &MI, unsigned Op) const
       { return 0; }
     uint32_t getAddrMode5OpValue(const MachineInstr &MI, unsigned Op) const {
diff --git a/lib/Target/ARM/ARMInstrFormats.td b/lib/Target/ARM/ARMInstrFormats.td
index 590ca09dfce..5c6d131125b 100644
--- a/lib/Target/ARM/ARMInstrFormats.td
+++ b/lib/Target/ARM/ARMInstrFormats.td
@@ -886,14 +886,20 @@ class AI3ldshpo<dag oops, dag iops, Format f, InstrItinClass itin,
                 string opc, string asm, string cstr, list<dag> pattern>
   : I<oops, iops, AddrMode3, Size4Bytes, IndexModePost, f, itin,
       opc, asm, cstr,pattern> {
-  let Inst{4}     = 1;
-  let Inst{5}     = 1; // H bit
-  let Inst{6}     = 1; // S bit
-  let Inst{7}     = 1;
-  let Inst{20}    = 1; // L bit
-  let Inst{21}    = 0; // W bit
-  let Inst{24}    = 0; // P bit
+  bits<10> offset;
+  bits<4> Rt;
+  bits<4> Rn;
   let Inst{27-25} = 0b000;
+  let Inst{24}    = 0;            // P bit
+  let Inst{23}    = offset{8};    // U bit
+  let Inst{22}    = offset{9};    // 1 == imm8, 0 == Rm
+  let Inst{21}    = 0;            // W bit
+  let Inst{20}    = 1;            // L bit
+  let Inst{19-16} = Rn;           // Rn
+  let Inst{15-12} = Rt;           // Rt
+  let Inst{11-8}  = offset{7-4};  // imm7_4/zero
+  let Inst{7-4}   = 0b1111;
+  let Inst{3-0}   = offset{3-0};  // imm3_0/Rm
 }
 class AI3ldsbpo<dag oops, dag iops, Format f, InstrItinClass itin,
                 string opc, string asm, string cstr, list<dag> pattern>
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index b592a1729ee..837a4fba0d5 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -450,6 +450,7 @@ def addrmode3 : Operand<i32>,
 def am3offset : Operand<i32>,
                 ComplexPattern<i32, 2, "SelectAddrMode3Offset",
                                [], [SDNPWantRoot]> {
+  string EncoderMethod = "getAddrMode3OffsetOpValue";
   let PrintMethod = "printAddrMode3OffsetOperand";
   let MIOperandInfo = (ops GPR, i32imm);
 }
diff --git a/lib/Target/ARM/ARMMCCodeEmitter.cpp b/lib/Target/ARM/ARMMCCodeEmitter.cpp
index da1080d51eb..89c0d2d058b 100644
--- a/lib/Target/ARM/ARMMCCodeEmitter.cpp
+++ b/lib/Target/ARM/ARMMCCodeEmitter.cpp
@@ -94,6 +94,10 @@ public:
     case ARM_AM::ib: return 3;
     }
   }
+  /// getAddrMode3OffsetOpValue - Return encoding for am3offset operands.
+  uint32_t getAddrMode3OffsetOpValue(const MCInst &MI, unsigned OpIdx,
+                                     SmallVectorImpl<MCFixup> &Fixups) const;
+
   /// getAddrMode3OpValue - Return encoding for addrmode3 operands.
   uint32_t getAddrMode3OpValue(const MCInst &MI, unsigned OpIdx,
                                SmallVectorImpl<MCFixup> &Fixups) const;
@@ -318,6 +322,25 @@ getLdStSORegOpValue(const MCInst &MI, unsigned OpIdx,
   return Binary;
 }
 
+uint32_t ARMMCCodeEmitter::
+getAddrMode3OffsetOpValue(const MCInst &MI, unsigned OpIdx,
+                          SmallVectorImpl<MCFixup> &Fixups) const {
+  // {9}      1 == imm8, 0 == Rm
+  // {8}      isAdd
+  // {7-4}    imm7_4/zero
+  // {3-0}    imm3_0/Rm
+  const MCOperand &MO = MI.getOperand(OpIdx);
+  const MCOperand &MO1 = MI.getOperand(OpIdx+1);
+  unsigned Imm = MO1.getImm();
+  bool isAdd = ARM_AM::getAM3Op(Imm) == ARM_AM::add;
+  bool isImm = MO.getReg() == 0;
+  uint32_t Imm8 = ARM_AM::getAM3Offset(Imm);
+  // if reg +/- reg, Rm will be non-zero. Otherwise, we have reg +/- imm8
+  if (!isImm)
+    Imm8 = getARMRegisterNumbering(MO.getReg());
+  return Imm8 | (isAdd << 8) | (isImm << 9);
+}
+
 uint32_t ARMMCCodeEmitter::
 getAddrMode3OpValue(const MCInst &MI, unsigned OpIdx,
                     SmallVectorImpl<MCFixup> &Fixups) const {