[Lldb-commits] [lldb] r125329 - in /lldb/trunk/source/Plugins/Instruction/ARM: EmulateInstructionARM.cpp EmulateInstructionARM.h

[Johnny Chen]

Author: johnny
Date: Thu Feb 10 19:29:53 2011
New Revision: 125329

URL: http://llvm.org/viewvc/llvm-project?rev=125329&view=rev
Log:
Add a helper method AddWithCarry() to the EmulateInstructionARM class.

Modified:
    lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
    lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.h

Modified: lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp?rev=125329&r1=125328&r2=125329&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp (original)
+++ lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp Thu Feb 10 19:29:53 2011
@@ -2595,6 +2595,27 @@
     return (ArchVersion() >= ARMv7);
 }
 
+// The main addition and subtraction instructions can produce status information
+// about both unsigned carry and signed overflow conditions.  This status
+// information can be used to synthesize multi-word additions and subtractions.
+EmulateInstructionARM::AddWithCarryResult
+EmulateInstructionARM::AddWithCarry (uint32_t x, uint32_t y, uint8_t carry_in)
+{
+    uint32_t result;
+    uint8_t carry_out;
+    uint8_t overflow;
+
+    uint64_t unsigned_sum = x + y + carry_in;
+    int64_t signed_sum = (int32_t)x + (int32_t)y + (int32_t)carry_in;
+    
+    result = UnsignedBits(unsigned_sum, 31, 0);
+    carry_out = (result == unsigned_sum ? 0 : 1);
+    overflow = ((int32_t)result == signed_sum ? 0 : 1);
+    
+    AddWithCarryResult res = { result, carry_out, overflow };
+    return res;
+}
+
 bool
 EmulateInstructionARM::EvaluateInstruction ()
 {

Modified: lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.h?rev=125329&r1=125328&r2=125329&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.h (original)
+++ lldb/trunk/source/Plugins/Instruction/ARM/EmulateInstructionARM.h Thu Feb 10 19:29:53 2011
@@ -169,6 +169,16 @@
     bool
     UnalignedSupport();
 
+    typedef struct
+    {
+        uint32_t result;
+        uint8_t carry_out;
+        uint8_t overflow;
+    } AddWithCarryResult;
+
+    AddWithCarryResult
+    AddWithCarry(uint32_t x, uint32_t y, uint8_t carry_in);
+
 protected:
 
     // Typedef for the callback function used during the emulation.