dyncom: Add a helper function for addition with a carry

3 files changed, 26 insertions, 12 deletions

diff --git a/src/core/arm/dyncom/arm_dyncom_interpreter.cpp b/src/core/arm/dyncom/arm_dyncom_interpreter.cpp
index bf864c7a..4c0a8f5c 100644
--- a/src/core/arm/dyncom/arm_dyncom_interpreter.cpp
+++ b/src/core/arm/dyncom/arm_dyncom_interpreter.cpp
@@ -4003,16 +4003,13 @@ unsigned InterpreterMainLoop(ARMul_State* state) {
     }
     ADC_INST:
     {
-        adc_inst *inst_cream = (adc_inst *)inst_base->component;
-        if ((inst_base->cond == 0xe) || CondPassed(cpu, inst_base->cond)) {
-            u32 left = RN;
-            u32 right = SHIFTER_OPERAND;
+        if (inst_base->cond == 0xE || CondPassed(cpu, inst_base->cond)) {
+            adc_inst* const inst_cream = (adc_inst*)inst_base->component;
 
-            u64 unsigned_sum = (left + right + cpu->CFlag);
-            s64 signed_sum = (s64)(s32)left + (s64)(s32)right + (s64)cpu->CFlag;
-            u32 result = (unsigned_sum & 0xFFFFFFFF);
+            bool carry;
+            bool overflow;
+            RD = AddWithCarry(RN, SHIFTER_OPERAND, cpu->CFlag, &carry, &overflow);
 
-            RD = result;
             if (inst_cream->S && (inst_cream->Rd == 15)) {
                 if (CurrentModeHasSPSR) {
                     cpu->Cpsr = cpu->Spsr_copy;
@@ -4020,10 +4017,10 @@ unsigned InterpreterMainLoop(ARMul_State* state) {
                     LOAD_NZCVT;
                 }
             } else if (inst_cream->S) {
-                UPDATE_NFLAG(result);
-                UPDATE_ZFLAG(result);
-                UPDATE_CFLAG_CARRY_FROM_ADD(left, right, cpu->CFlag);
-                cpu->VFlag = ((s64)(s32)result != signed_sum);
+                UPDATE_NFLAG(RD);
+                UPDATE_ZFLAG(RD);
+                cpu->CFlag = carry;
+                cpu->VFlag = overflow;
             }
             if (inst_cream->Rd == 15) {
                 INC_PC(sizeof(adc_inst));
diff --git a/src/core/arm/interpreter/armsupp.cpp b/src/core/arm/interpreter/armsupp.cpp
index 68ac2a0c..e2626eef 100644
--- a/src/core/arm/interpreter/armsupp.cpp
+++ b/src/core/arm/interpreter/armsupp.cpp
@@ -418,6 +418,22 @@ ARMul_NegZero (ARMul_State * state, ARMword result)
     }
 }
 
+// Add with carry, indicates if a carry-out or signed overflow occurred.
+u32 AddWithCarry(u32 left, u32 right, u32 carry_in, bool* carry_out_occurred, bool* overflow_occurred)
+{
+    u64 unsigned_sum = (u64)left + (u64)right + (u64)carry_in;
+    s64 signed_sum = (s64)(s32)left + (s64)(s32)right + (s64)carry_in;
+    u64 result = (unsigned_sum & 0xFFFFFFFF);
+
+    if (carry_out_occurred)
+        *carry_out_occurred = (result != unsigned_sum);
+
+    if (overflow_occurred)
+        *overflow_occurred = ((s64)(s32)result != signed_sum);
+
+    return (u32)result;
+}
+
 // Compute whether an addition of A and B, giving RESULT, overflowed.
 bool AddOverflow(ARMword a, ARMword b, ARMword result)
 {
diff --git a/src/core/arm/skyeye_common/armdefs.h b/src/core/arm/skyeye_common/armdefs.h
index 1b2cef45..560b51a9 100644
--- a/src/core/arm/skyeye_common/armdefs.h
+++ b/src/core/arm/skyeye_common/armdefs.h
@@ -795,6 +795,7 @@ extern void ARMul_FixSPSR(ARMul_State*, ARMword, ARMword);
 extern void ARMul_ConsolePrint(ARMul_State*, const char*, ...);
 extern void ARMul_SelectProcessor(ARMul_State*, unsigned);
 
+extern u32 AddWithCarry(u32, u32, u32, bool*, bool*);
 extern bool ARMul_AddOverflowQ(ARMword, ARMword);
 
 extern u8 ARMul_SignedSaturatedAdd8(u8, u8);