From f0eee6eca8c39b11b6a41d9b04eba8985655df77 Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Wed, 7 Sep 2011 23:39:14 +0000
Subject: [PATCH] Thumb2 assembly parsing and encoding for LDRBT.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139267 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstrThumb2.td          | 26 +++++++++++++++++---------
 lib/Target/ARM/AsmParser/ARMAsmParser.cpp | 17 +++++++++++++----
 test/MC/ARM/basic-thumb2-instructions.s   | 14 ++++++++++++++
 utils/TableGen/EDEmitter.cpp              |  1 +
 4 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index bb9debd7696..2857b2d208e 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -123,6 +123,16 @@ def t2adrlabel : Operand<i32> {
 }
 
 
+// t2addrmode_posimm8  := reg + imm8
+def MemPosImm8OffsetAsmOperand : AsmOperandClass {let Name="MemPosImm8Offset";}
+def t2addrmode_posimm8 : Operand<i32> {
+  let PrintMethod = "printT2AddrModeImm8Operand";
+  let EncoderMethod = "getT2AddrModeImm8OpValue";
+  let DecoderMethod = "DecodeT2AddrModeImm8";
+  let ParserMatchClass = MemPosImm8OffsetAsmOperand;
+  let MIOperandInfo = (ops GPR:$base, i32imm:$offsimm);
+}
+
 // t2addrmode_negimm8  := reg - imm8
 def MemNegImm8OffsetAsmOperand : AsmOperandClass {let Name="MemNegImm8Offset";}
 def t2addrmode_negimm8 : Operand<i32>,
@@ -1291,26 +1301,24 @@ def t2LDRSH_POST : T2Iidxldst<1, 0b01, 1, 0, (outs GPR:$Rt, GPR:$Rn),
                             []>;
 } // mayLoad = 1, neverHasSideEffects = 1
 
-// LDRT, LDRBT, LDRHT, LDRSBT, LDRSHT all have offset mode (PUW=0b110) and are
-// for disassembly only.
+// LDRT, LDRBT, LDRHT, LDRSBT, LDRSHT all have offset mode (PUW=0b110).
 // Ref: A8.6.57 LDR (immediate, Thumb) Encoding T4
 class T2IldT<bit signed, bits<2> type, string opc, InstrItinClass ii>
-  : T2Ii8<(outs rGPR:$Rt), (ins t2addrmode_imm8:$addr), ii, opc,
+  : T2Ii8<(outs rGPR:$Rt), (ins t2addrmode_posimm8:$addr), ii, opc,
           "\t$Rt, $addr", []> {
+  bits<4> Rt;
+  bits<13> addr;
   let Inst{31-27} = 0b11111;
   let Inst{26-25} = 0b00;
   let Inst{24} = signed;
   let Inst{23} = 0;
   let Inst{22-21} = type;
   let Inst{20} = 1; // load
+  let Inst{19-16} = addr{12-9};
+  let Inst{15-12} = Rt;
   let Inst{11} = 1;
   let Inst{10-8} = 0b110; // PUW.
-
-  bits<4> Rt;
-  bits<13> addr;
-  let Inst{15-12} = Rt;
-  let Inst{19-16} = addr{12-9};
-  let Inst{7-0}   = addr{7-0};
+  let Inst{7-0} = addr{7-0};
 }
 
 def t2LDRT   : T2IldT<0, 0b10, "ldrt", IIC_iLoad_i>;
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 6df2d56ff2c..b66adfc9048 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -742,6 +742,14 @@ public:
     int64_t Val = Mem.OffsetImm->getValue();
     return Val > -256 && Val < 256;
   }
+  bool isMemPosImm8Offset() const {
+    if (Kind != Memory || Mem.OffsetRegNum != 0)
+      return false;
+    // Immediate offset in range [0, 255].
+    if (!Mem.OffsetImm) return true;
+    int64_t Val = Mem.OffsetImm->getValue();
+    return Val >= 0 && Val < 256;
+  }
   bool isMemNegImm8Offset() const {
     if (Kind != Memory || Mem.OffsetRegNum != 0)
       return false;
@@ -1108,11 +1116,12 @@ public:
     Inst.addOperand(MCOperand::CreateImm(Val));
   }
 
+  void addMemPosImm8OffsetOperands(MCInst &Inst, unsigned N) const {
+    addMemImm8OffsetOperands(Inst, N);
+  }
+
   void addMemNegImm8OffsetOperands(MCInst &Inst, unsigned N) const {
-    assert(N == 2 && "Invalid number of operands!");
-    int64_t Val = Mem.OffsetImm ? Mem.OffsetImm->getValue() : 0;
-    Inst.addOperand(MCOperand::CreateReg(Mem.BaseRegNum));
-    Inst.addOperand(MCOperand::CreateImm(Val));
+    addMemImm8OffsetOperands(Inst, N);
   }
 
   void addMemUImm12OffsetOperands(MCInst &Inst, unsigned N) const {
diff --git a/test/MC/ARM/basic-thumb2-instructions.s b/test/MC/ARM/basic-thumb2-instructions.s
index 4fc9391f88b..1abbd5fa788 100644
--- a/test/MC/ARM/basic-thumb2-instructions.s
+++ b/test/MC/ARM/basic-thumb2-instructions.s
@@ -592,6 +592,20 @@ _func:
 
 
 @------------------------------------------------------------------------------
+@ LDRBT
+@------------------------------------------------------------------------------
+        ldrbt r1, [r2]
+        ldrbt r1, [r8, #0]
+        ldrbt r1, [r8, #3]
+        ldrbt r1, [r8, #255]
+
+@ CHECK: ldrbt	r1, [r2]                @ encoding: [0x12,0xf8,0x00,0x1e]
+@ CHECK: ldrbt	r1, [r8]                @ encoding: [0x18,0xf8,0x00,0x1e]
+@ CHECK: ldrbt	r1, [r8, #3]            @ encoding: [0x18,0xf8,0x03,0x1e]
+@ CHECK: ldrbt	r1, [r8, #255]          @ encoding: [0x18,0xf8,0xff,0x1e]
+
+
+@------------------------------------------------------------------------------
 @ IT
 @------------------------------------------------------------------------------
 @ Test encodings of a few full IT blocks, not just the IT instruction
diff --git a/utils/TableGen/EDEmitter.cpp b/utils/TableGen/EDEmitter.cpp
index 0a1e4af4180..11de085d9ae 100644
--- a/utils/TableGen/EDEmitter.cpp
+++ b/utils/TableGen/EDEmitter.cpp
@@ -666,6 +666,7 @@ static int ARMFlagFromOpName(LiteralConstantEmitter *type,
   MISC("spr_reglist", "kOperandTypeARMSPRRegisterList");          // I, R, ...
   MISC("it_mask", "kOperandTypeThumbITMask");                     // I
   MISC("t2addrmode_reg", "kOperandTypeThumb2AddrModeReg");        // R
+  MISC("t2addrmode_posimm8", "kOperandTypeThumb2AddrModeImm8");   // R, I
   MISC("t2addrmode_negimm8", "kOperandTypeThumb2AddrModeImm8");   // R, I
   MISC("t2addrmode_imm8", "kOperandTypeThumb2AddrModeImm8");      // R, I
   MISC("t2am_imm8_offset", "kOperandTypeThumb2AddrModeImm8Offset");//I
-- 
2.11.0