diff --git a/src/mame/apple/apple2common.cpp b/src/mame/apple/apple2common.cpp
index 317f4061cc6..f716bc87994 100644
--- a/src/mame/apple/apple2common.cpp
+++ b/src/mame/apple/apple2common.cpp
@@ -805,7 +805,7 @@ offs_t apple2_common_device::dasm_override_GS(std::ostream &stream, offs_t pc, c
 				if (operand == 0xe100a8)
 				{
 					u16 call = opcodes.r8(pc + 4);
-					u32 params = opcodes.r16(pc + 6) & 0xffffff;
+					u32 params = opcodes.r32(pc + 6) & 0xffffff;
 					int item = 0;
 
 					while (gsos_calls[item].addr != 0xffff)