arch-arm: Disassemble operands to LDP/STP instructions

ldp/stp are split into uops which include the src & dest for each reg,
but tarmac trace only shows the ops and not the uops.

This is annoying because ldp/stp is extremely common (eg for function
entry/exit).

Change-Id: Ib88dfbfff887ad7450bd846fe0d2e4cdc75c513b

Author: bpfoley

src/arch/arm/insts/macromem.cc

@@ -246,7 +246,12 @@ PairMemOp::PairMemOp(const char *mnem, ExtMachInst machInst, OpClass __opClass,
                      bool signExt, bool exclusive, bool acrel,
                      int64_t imm, AddrMode mode,
                      RegIndex rn, RegIndex rt, RegIndex rt2) :
-    PredMacroOp(mnem, machInst, __opClass)
+    PredMacroOp(mnem, machInst, __opClass),
+    mode(mode),
+    rn(rn),
+    rt(rt),
+    rt2(rt2),
+    imm(imm)
 {
     bool post = (mode == AddrMd_PostIndex);
     bool writeback = (mode != AddrMd_Offset);
@@ -1643,5 +1648,31 @@ MicroMemPairOp::generateDisassembly(
     return ss.str();
 }
 
+std::string
+PairMemOp::generateDisassembly(
+        Addr pc, const loader::SymbolTable *symtab) const
+{
+    std::stringstream ss;
+    printMnemonic(ss);
+    printIntReg(ss, rt);
+    ss << ", ";
+    printIntReg(ss, rt2);
+    ss << ", [";
+    printIntReg(ss, rn, 64);
+    if (mode == AddrMd_PostIndex) {
+        ss << "]";
+    }
+    if (imm) {
+        ccprintf(ss, ", #%d", imm);
+    }
+    if (mode != AddrMd_PostIndex) {
+        ss << "]";
+    }
+    if (mode == AddrMd_PreIndex) {
+        ss << "!";
+    }
+    return ss.str();
+}
+
 } // namespace ArmISA
 } // namespace gem5

src/arch/arm/insts/macromem.hh

@@ -481,10 +481,16 @@ class PairMemOp : public PredMacroOp
     };
 
   protected:
+    AddrMode mode;
+    RegIndex rn, rt, rt2;
+    int32_t imm;
     PairMemOp(const char *mnem, ExtMachInst machInst, OpClass __opClass,
               uint32_t size, bool fp, bool load, bool noAlloc, bool signExt,
               bool exclusive, bool acrel, int64_t imm, AddrMode mode,
               RegIndex rn, RegIndex rt, RegIndex rt2);
+
+    std::string generateDisassembly(
+            Addr pc, const loader::SymbolTable *symtab) const override;
 };
 
 class BigFpMemImmOp : public PredMacroOp