Merge pull request #388 from lioncash/sm

dyncom: Implement SMLAD/SMUAD/SMLSD/SMUSD

2 files changed, 15 insertions, 7 deletions

diff --git a/src/core/arm/interpreter/armemu.cpp b/src/core/arm/interpreter/armemu.cpp
index 43b1ba40e..12166bf79 100644
--- a/src/core/arm/interpreter/armemu.cpp
+++ b/src/core/arm/interpreter/armemu.cpp
@@ -6470,17 +6470,23 @@ L_stm_s_takeabort:
 
                     if (BITS(12, 15) != 15) {
                         state->Reg[rd_idx] += state->Reg[ra_idx];
-                        ARMul_AddOverflowQ(state, product1 + product2, state->Reg[ra_idx]);
+                        if (ARMul_AddOverflowQ(product1 + product2, state->Reg[ra_idx]))
+                            SETQ;
                     }
 
-                    ARMul_AddOverflowQ(state, product1, product2);
+                    if (ARMul_AddOverflowQ(product1, product2))
+                        SETQ;
                 }
                 // SMUSD and SMLSD
                 else {
                     state->Reg[rd_idx] = product1 - product2;
-                    
-                    if (BITS(12, 15) != 15)
+
+                    if (BITS(12, 15) != 15) {
                         state->Reg[rd_idx] += state->Reg[ra_idx];
+
+                        if (ARMul_AddOverflowQ(product1 - product2, state->Reg[ra_idx]))
+                            SETQ;
+                    }
                 }
 
                 return 1;
diff --git a/src/core/arm/interpreter/armsupp.cpp b/src/core/arm/interpreter/armsupp.cpp
index 426b67831..eec34143e 100644
--- a/src/core/arm/interpreter/armsupp.cpp
+++ b/src/core/arm/interpreter/armsupp.cpp
@@ -453,12 +453,14 @@ ARMul_AddOverflow (ARMul_State * state, ARMword a, ARMword b, ARMword result)
     ASSIGNV (AddOverflow (a, b, result));
 }
 
-/* Assigns the Q flag if the given result is considered an overflow from the addition of a and b  */
-void ARMul_AddOverflowQ(ARMul_State* state, ARMword a, ARMword b)
+// Returns true if the Q flag should be set as a result of overflow.
+bool ARMul_AddOverflowQ(ARMword a, ARMword b)
 {
     u32 result = a + b;
     if (((result ^ a) & (u32)0x80000000) && ((a ^ b) & (u32)0x80000000) == 0)
-        SETQ;
+        return true;
+
+    return false;
 }
 
 /* Assigns the C flag after an subtraction of a and b to give result.  */