From 7f09510945d35b0029552875373e17127335bcd5 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Sun, 17 Jul 2016 13:29:37 -0500
Subject: [PATCH] Implemented ARM CMP (imm) instruction.

---
 src/frontend/decoder/arm.h               |  4 ++--
 src/frontend/translate/translate_arm.cpp | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/frontend/decoder/arm.h b/src/frontend/decoder/arm.h
index 62f8cfda..041b5bc5 100644
--- a/src/frontend/decoder/arm.h
+++ b/src/frontend/decoder/arm.h
@@ -59,7 +59,7 @@ private:
 };
 
 template <typename V>
-static const std::array<ArmMatcher<V>, 3> g_arm_instruction_table = {
+static const std::array<ArmMatcher<V>, 4> g_arm_instruction_table = {
 
 #define INST(fn, name, bitstring) detail::detail<ArmMatcher, u32, 32>::GetMatcher<decltype(fn), fn>(name, bitstring)
 
@@ -103,7 +103,7 @@ static const std::array<ArmMatcher<V>, 3> g_arm_instruction_table = {
     //INST(&V::arm_CMN_imm,     "CMN (imm)",           "cccc00110111nnnn0000rrrrvvvvvvvv"), // all
     //INST(&V::arm_CMN_reg,     "CMN (reg)",           "cccc00010111nnnn0000vvvvvrr0mmmm"), // all
     //INST(&V::arm_CMN_rsr,     "CMN (rsr)",           "cccc00010111nnnn0000ssss0rr1mmmm"), // all
-    //INST(&V::arm_CMP_imm,     "CMP (imm)",           "cccc00110101nnnn0000rrrrvvvvvvvv"), // all
+    INST(&V::arm_CMP_imm,     "CMP (imm)",           "cccc00110101nnnn0000rrrrvvvvvvvv"), // all
     //INST(&V::arm_CMP_reg,     "CMP (reg)",           "cccc00010101nnnn0000vvvvvrr0mmmm"), // all
     //INST(&V::arm_CMP_rsr,     "CMP (rsr)",           "cccc00010101nnnn0000ssss0rr1mmmm"), // all
     //INST(&V::arm_EOR_imm,     "EOR (imm)",           "cccc0010001Snnnnddddrrrrvvvvvvvv"), // all
diff --git a/src/frontend/translate/translate_arm.cpp b/src/frontend/translate/translate_arm.cpp
index 71b9fe26..cfdfc8bc 100644
--- a/src/frontend/translate/translate_arm.cpp
+++ b/src/frontend/translate/translate_arm.cpp
@@ -156,9 +156,20 @@ struct ArmTranslatorVisitor final {
     bool arm_CMN_rsr(Cond cond, Reg n, Reg s, ShiftType shift, Reg m) {
         return InterpretThisInstruction();
     }
+
     bool arm_CMP_imm(Cond cond, Reg n, int rotate, Imm8 imm8) {
-        return InterpretThisInstruction();
+        u32 imm32 = ArmExpandImm(rotate, imm8);
+        // CMP<c> <Rn>, #<imm>
+        if (ConditionPassed(cond)) {
+            auto result = ir.AddWithCarry(ir.GetRegister(n), ir.Imm32(~imm32), ir.Imm1(true));
+            ir.SetNFlag(ir.MostSignificantBit(result.result));
+            ir.SetZFlag(ir.IsZero(result.result));
+            ir.SetCFlag(result.carry);
+            ir.SetVFlag(result.overflow);
+        }
+        return true;
     }
+
     bool arm_CMP_reg(Cond cond, Reg n, Imm5 imm5, ShiftType shift, Reg m) {
         return InterpretThisInstruction();
     }