diff --git a/src/da65/main.c b/src/da65/main.c
index 8d68dc4cc..67a01dc3b 100644
--- a/src/da65/main.c
+++ b/src/da65/main.c
@@ -64,6 +64,8 @@
 #include "segment.h"
 
 
+static unsigned PrevAddrMode;
+
 
 /*****************************************************************************/
 /*                                   Code                                    */
@@ -442,6 +444,22 @@ static void OneOpcode (unsigned RemainingBytes)
             ** following insn, fall through to byte mode.
             */
             if (D->Size <= RemainingBytes) {
+                if (CPU == CPU_65816) {
+                    const unsigned AddrMode = GetAttr (PC) & at65816Mask;
+                    if (PrevAddrMode != AddrMode) {
+                        if ((PrevAddrMode & atMem8) != (AddrMode & atMem8) ||
+                            (PrevAddrMode & atMem16) != (AddrMode & atMem16)) {
+                            OutputMFlag(!!(AddrMode & atMem8));
+                        }
+                        if ((PrevAddrMode & atIdx8) != (AddrMode & atIdx8) ||
+                            (PrevAddrMode & atIdx16) != (AddrMode & atIdx16)) {
+                            OutputXFlag(!!(AddrMode & atIdx8));
+                        }
+
+                        PrevAddrMode = AddrMode;
+                    }
+                }
+
                 /* Output labels within the next insn */
                 for (I = 1; I < D->Size; ++I) {
                     ForwardLabel (I);
@@ -517,6 +535,8 @@ static void OnePass (void)
 {
     unsigned Count;
 
+    PrevAddrMode = 0;
+
     /* Disassemble until nothing left */
     while ((Count = GetRemainingBytes()) > 0) {
         OneOpcode (Count);
diff --git a/src/da65/output.c b/src/da65/output.c
index 5b0b6b79c..8e786e130 100644
--- a/src/da65/output.c
+++ b/src/da65/output.c
@@ -401,3 +401,23 @@ void OutputSettings (void)
     LineFeed ();
     LineFeed ();
 }
+
+
+
+void OutputMFlag (unsigned char enabled)
+/* Output the 65816 M-flag state */
+{
+    Indent (MCol);
+    Output (enabled ? ".a8" : ".a16");
+    LineFeed ();
+}
+
+
+
+void OutputXFlag (unsigned char enabled)
+/* Output the 65816 X-flag state */
+{
+    Indent (MCol);
+    Output (enabled ? ".i8" : ".i16");
+    LineFeed ();
+}
diff --git a/src/da65/output.h b/src/da65/output.h
index 13ea0cc85..bc20aace0 100644
--- a/src/da65/output.h
+++ b/src/da65/output.h
@@ -108,6 +108,12 @@ void LineComment (unsigned PC, unsigned Count);
 void OutputSettings (void);
 /* Output CPU and other settings */
 
+void OutputMFlag (unsigned char enabled);
+/* Output the 65816 M-flag state */
+
+void OutputXFlag (unsigned char enabled);
+/* Output the 65816 X-flag state */
+
 
 
 /* End of output.h */