Add code to emulate LDMDB Arm instruction.

llvm-svn: 125133

lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp

@@ -1617,6 +1617,142 @@ EmulateInstructionARM::EmulateLDM (ARMEncoding encoding)
     return true;
 }
                   
+bool
+EmulateInstructionARM::EmulateLDMDB (ARMEncoding encoding)
+{
+#if 0
+    // ARM pseudo code...
+    if ConditionPassed() then 
+        EncodingSpecificOperations(); NullCheckIfThumbEE(n); 
+        address = R[n] - 4*BitCount(registers);
+                  
+        for i = 0 to 14 
+            if registers<i> == ’1’ then
+                  R[i] = MemA[address,4]; address = address + 4; 
+        if registers<15> == ’1’ then
+                  LoadWritePC(MemA[address,4]);
+                  
+        if wback && registers<n> == ’0’ then R[n] = R[n] - 4*BitCount(registers); 
+        if wback && registers<n> == ’1’ then R[n] = bits(32) UNKNOWN; // Only possible for encoding A1
+#endif
+                  
+    bool success = false;
+    const uint32_t opcode = OpcodeAsUnsigned (&success);
+    if (!success)
+        return false;
+                  
+    if (ConditionPassed())
+    {
+        uint32_t n;
+        uint32_t registers = 0;
+        bool wback;
+        const uint32_t addr_byte_size = GetAddressByteSize();
+        switch (encoding)
+        {
+            case eEncodingT1:
+                // n = UInt(Rn); registers = P:M:’0’:register_list; wback = (W == ’1’);
+                n = Bits32 (opcode, 19, 16);
+                registers = Bits32 (opcode, 15, 0);
+                wback = BitIsSet (opcode, 21);
+
+                // if n == 15 || BitCount(registers) < 2 || (P == ’1’ && M == ’1’) then UNPREDICTABLE;
+                if ((n == 15)
+                    || (BitCount (registers) < 2)
+                    || (BitIsSet (opcode, 14) && BitIsSet (opcode, 15)))
+                    return false;
+
+                // if registers<15> == ’1’ && InITBlock() && !LastInITBlock() then UNPREDICTABLE;
+                if (BitIsSet (registers, 15)
+                    && m_it_session.InITBlock()
+                    && !m_it_session.LastInITBlock())
+                    return false;
+
+                // if wback && registers<n> == ’1’ then UNPREDICTABLE;
+                if (wback && BitIsSet (registers, n))
+                    return false;
+                  
+                break;
+                  
+            case eEncodingA1:
+                // n = UInt(Rn); registers = register_list; wback = (W == ’1’);
+                n = Bits32 (opcode, 19, 16);
+                registers = Bits32 (opcode, 15, 0);
+                wback = BitIsSet (opcode, 21);
+                  
+                // if n == 15 || BitCount(registers) < 1 then UNPREDICTABLE;
+                if ((n == 15) || (BitCount (registers) < 1))
+                    return false;
+                  
+                break;
+                  
+            default:
+                return false;
+        }
+                  
+        int32_t offset = 0;
+        addr_t address = ReadRegisterUnsigned (eRegisterKindDWARF, dwarf_r0 + n, 0, &success) 
+                                                                             - (addr_byte_size * BitCount (registers));
+                  
+        for (int i = 0; i < 14; ++i)
+        {
+            if (BitIsSet (registers, i))
+            {
+                // R[i] = MemA[address,4]; address = address + 4;
+                EmulateInstruction::Context context = { EmulateInstruction::eContextRegisterPlusOffset,
+                                                        eRegisterKindDWARF,
+                                                        dwarf_r0 + n,
+                                                        offset };
+
+                uint32_t data = ReadMemoryUnsigned (context, address + offset, addr_byte_size, 0, &success);
+                if (!success)
+                    return false;
+                  
+                if (!WriteRegisterUnsigned (context, eRegisterKindDWARF, dwarf_r0 + i, data))
+                    return false;
+                  
+                offset += addr_byte_size;
+            }
+        }
+                  
+        // if registers<15> == ’1’ then
+        //     LoadWritePC(MemA[address,4]);
+        if (BitIsSet (registers, 15))
+        {
+            EmulateInstruction::Context context = { EmulateInstruction::eContextRegisterPlusOffset,
+                                                    eRegisterKindDWARF,
+                                                    dwarf_r0 + n,
+                                                    offset };
+                  
+            uint32_t data = ReadMemoryUnsigned (context, address + offset, addr_byte_size, 0, &success);
+            if (!success)
+                return false;
+            if (!WriteRegisterUnsigned (context, eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, data))
+                return false;
+        }
+                  
+        // if wback && registers<n> == ’0’ then R[n] = R[n] - 4*BitCount(registers);
+        if (wback && BitIsClear (registers, n))
+        {
+            EmulateInstruction::Context context = { EmulateInstruction::eContextRegisterPlusOffset,
+                                                    eRegisterKindDWARF,
+                                                    dwarf_r0 + n,
+                                                    offset };
+                  
+            addr_t addr = ReadRegisterUnsigned (eRegisterKindDWARF, dwarf_r0 + n, 0, &success);
+            if (!success)
+                return false;
+            addr = addr - (addr_byte_size * BitCount (registers));
+            if (!WriteRegisterUnsigned (context, eRegisterKindDWARF, dwarf_r0 + n, addr))
+                return false;
+        }
+                  
+        // if wback && registers<n> == ’1’ then R[n] = bits(32) UNKNOWN; // Only possible for encoding A1
+        if (wback && BitIsSet (registers, n))
+            return false;  // I'm not sure this is right; how do I set R[n] to bits(32) UNKNOWN.
+    }
+    return true;
+}
+                  
 EmulateInstructionARM::ARMOpcode*
 EmulateInstructionARM::GetARMOpcodeForInstruction (const uint32_t opcode)
 {
@@ -1676,7 +1812,8 @@ EmulateInstructionARM::GetARMOpcodeForInstruction (const uint32_t opcode)
         //----------------------------------------------------------------------
         // Load instructions
         //----------------------------------------------------------------------
-        { 0x0fd00000, 0x08900000, ARMvAll,       eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDM, "ldm<c> <Rn>{!} <registers>" }
+        { 0x0fd00000, 0x08900000, ARMvAll,       eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDM, "ldm<c> <Rn>{!} <registers>" },
+        { 0x0fd00000, 0x09100000, ARMvAll,       eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDMDB, "ldmdb<c> <Rn>{!} <registers>" }
         
     };
     static const size_t k_num_arm_opcodes = sizeof(g_arm_opcodes)/sizeof(ARMOpcode);
@@ -1765,7 +1902,8 @@ EmulateInstructionARM::GetThumbOpcodeForInstruction (const uint32_t opcode)
         // Load instructions
         //----------------------------------------------------------------------
         { 0xfffff800, 0x0000c800, ARMV4T_ABOVE,  eEncodingT1, eSize16, &EmulateInstructionARM::EmulateLDM, "ldm<c> <Rn>{!} <registers>" },
-        { 0xffd02000, 0xe8900000, ARMV6T2_ABOVE, eEncodingT2, eSize32, &EmulateInstructionARM::EmulateLDM, "ldm<c>.w <Rn>{!} <registers>" }
+        { 0xffd02000, 0xe8900000, ARMV6T2_ABOVE, eEncodingT2, eSize32, &EmulateInstructionARM::EmulateLDM, "ldm<c>.w <Rn>{!} <registers>" },
+        { 0xffd00000, 0xe9100000, ARMV6T2_ABOVE, eEncodingT1, eSize32, &EmulateInstructionARM::EmulateLDMDB, "ldmdb<c> <Rn>{!} <registers>" }
         
     };
 

lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.h

@@ -238,6 +238,9 @@ protected:
     
     bool
     EmulateLDM (ARMEncoding encoding);
+    
+    bool 
+    EmulateLDMDB (ARMEncoding encoding);
 
     uint32_t m_arm_isa;
     Mode m_inst_mode;