diff --git a/src/gba/GBA-arm.cpp b/src/gba/GBA-arm.cpp
index 4c575ada..2f428dae 100644
--- a/src/gba/GBA-arm.cpp
+++ b/src/gba/GBA-arm.cpp
@@ -991,9 +991,9 @@ static void count(u32 opcode, int cond_res)
 #endif
 #ifndef OP_RSC
  #define OP_RSC \
-    u32 lhs = reg[(opcode>>16)&15].I;                   \
-    u32 rhs = value;                                    \
-    u32 res = rhs - lhs - !((u32)C_FLAG);               \
+    u32 lhs = value;                                    \
+    u32 rhs = reg[(opcode>>16)&15].I;                   \
+    u32 res = lhs - rhs - !((u32)C_FLAG);               \
     reg[dest].I = res;
 #endif
 #ifndef OP_RSCS
@@ -2947,4 +2947,4 @@ int armExecute()
     } while (cpuTotalTicks<cpuNextEvent && armState && !holdState && !SWITicks);
 
     return 1;
-}
+}
\ No newline at end of file