diff --git a/src/devices/cpu/st9/st9dasm.cpp b/src/devices/cpu/st9/st9dasm.cpp
index fa8c2a6abf5..2ec5f955110 100644
--- a/src/devices/cpu/st9/st9dasm.cpp
+++ b/src/devices/cpu/st9/st9dasm.cpp
@@ -1222,9 +1222,9 @@ offs_t st9_disassembler::disassemble(std::ostream &stream, offs_t pc, const st9_
 	{
 		const u8 byte1 = opcodes.r8(pc + 1);
 		if (BIT(byte1, 0))
-			util::stream_format(stream, "%-8sr%d,(rr%d)", "ld", byte1 >> 4, byte1 & 0x0e);
-		else
 			util::stream_format(stream, "%-8s(rr%d),r%d", "ld", byte1 & 0x0e, byte1 >> 4);
+		else
+			util::stream_format(stream, "%-8sr%d,(rr%d)", "ld", byte1 >> 4, byte1 & 0x0e);
 		return 2 | SUPPORTED;
 	}