diff --git a/include/xhdi_sd.h b/include/xhdi_sd.h
index b7dc772..d05190d 100644
--- a/include/xhdi_sd.h
+++ b/include/xhdi_sd.h
@@ -87,9 +87,9 @@ typedef void* (*xhdi_call_fun)(int xhdi_fun, ...);
 struct XHDICALL_args
 {
 	uint16_t opcode;
-} __attribute__((packed));
+};
 
-extern uint32_t xhdi_call(struct XHDICALL_args *stack);
+extern unsigned long xhdi_call(struct XHDICALL_args stack);
 
 extern xhdi_call_fun xhdi_sd_install(xhdi_call_fun old_vector) __attribute__((__interrupt__));
 
diff --git a/sources/xhdi_interface.c b/sources/xhdi_interface.c
index 4d19b33..bc1d3ff 100644
--- a/sources/xhdi_interface.c
+++ b/sources/xhdi_interface.c
@@ -27,9 +27,9 @@
 #include "bas_printf.h"
 
 
-uint32_t xhdi_call(uint16_t *stack)
+unsigned long xhdi_call(struct XHDICALL_args stack)
 {
-	uint16_t opcode = *stack;
+	uint16_t opcode = stack.opcode;
 
 	xprintf("xhdi_call(): opcode %d\r\n", opcode);
 
@@ -49,7 +49,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint32_t *blocksize;
 			uint32_t *deviceflags;
 			char *productname;
-		}*args = (struct XHINQTARGET_args *) stack;
+		}*args = (struct XHINQTARGET_args *) &stack;
 
 		return xhdi_inquire_target(args->major, args->minor, args->blocksize,
 				args->deviceflags, args->productname);
@@ -65,7 +65,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t minor;
 			uint16_t do_reserve;
 			uint16_t key;
-		}*args = (struct XHRESERVE_args *) stack;
+		}*args = (struct XHRESERVE_args *) &stack;
 
 		return xhdi_reserve(args->major, args->minor, args->do_reserve, args->key);
 	}
@@ -79,7 +79,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t minor;
 			uint16_t do_lock;
 			uint16_t key;
-		}*args = (struct XHLOCK_args *) stack;
+		}*args = (struct XHLOCK_args *) &stack;
 
 		return xhdi_lock(args->major, args->minor, args->do_lock, args->key);
 	}
@@ -93,7 +93,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t minor;
 			uint16_t do_stop;
 			uint16_t key;
-		}*args = (struct XHSTOP_args *) stack;
+		}*args = (struct XHSTOP_args *) &stack;
 
 		return xhdi_stop(args->major, args->minor, args->do_stop, args->key);
 	}
@@ -107,7 +107,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t minor;
 			uint16_t do_eject;
 			uint16_t key;
-		}*args = (struct XHEJECT_args *) stack;
+		}*args = (struct XHEJECT_args *) &stack;
 
 		return xhdi_eject(args->major, args->minor, args->do_eject, args->key);
 	}
@@ -127,7 +127,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t *minor;
 			uint32_t *start;
 			BPB *bpb;
-		}*args = (struct XHINQDEV_args *) stack;
+		}*args = (struct XHINQDEV_args *) &stack;
 
 		return xhdi_inquire_device(args->drv, args->major, args->minor, args->start,
 				args->bpb);
@@ -144,7 +144,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			char *company;
 			uint16_t *ahdi_version;
 			uint16_t *maxIPL;
-		}*args = (struct XHINQDRIVER_args *) stack;
+		}*args = (struct XHINQDRIVER_args *) &stack;
 
 		return xhdi_inquire_driver(args->dev, args->name, args->version, args->company,
 				args->ahdi_version, args->maxIPL);
@@ -156,7 +156,7 @@ uint32_t xhdi_call(uint16_t *stack)
 		{
 			uint16_t opcode;
 			uint32_t newcookie;
-		}*args = (struct XHNEWCOOKIE_args *) stack;
+		}*args = (struct XHNEWCOOKIE_args *) &stack;
 
 		return xhdi_new_cookie(args->newcookie);
 	}
@@ -172,7 +172,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint32_t sector;
 			uint16_t count;
 			void *buf;
-		}*args = (struct XHREADWRITE_args *) stack;
+		}*args = (struct XHREADWRITE_args *) &stack;
 
 		return xhdi_read_write(args->major, args->minor, args->rw, args->sector,
 				args->count, args->buf);
@@ -189,7 +189,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint32_t *deviceflags;
 			char *productname;
 			uint16_t stringlen;
-		}*args = (struct XHINQTARGET2_args *) stack;
+		}*args = (struct XHINQTARGET2_args *) &stack;
 
 		return xhdi_inquire_target2(args->major, args->minor, args->blocksize,
 				args->deviceflags, args->productname, args->stringlen);
@@ -207,7 +207,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			BPB *bpb;
 			uint32_t *blocks;
 			char *partid;
-		}*args = (struct XHINQDEV2_args *) stack;
+		}*args = (struct XHINQDEV2_args *) &stack;
 
 		return xhdi_inquire_device2(args->drv, args->major, args->minor, args->start,
 				args->bpb, args->blocks, args->partid);
@@ -222,7 +222,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint32_t key2;
 			uint16_t subopcode;
 			void *data;
-		}*args = (struct XHDRIVERSPECIAL_args *) stack;
+		}*args = (struct XHDRIVERSPECIAL_args *) &stack;
 
 		return xhdi_driver_special(args->key1, args->key2, args->subopcode,
 				args->data);
@@ -237,7 +237,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t minor;
 			uint32_t *blocks;
 			uint32_t *blocksize;
-		}*args = (struct XHGETCAPACITY_args *) stack;
+		}*args = (struct XHGETCAPACITY_args *) &stack;
 
 		return xhdi_get_capacity(args->major, args->minor, args->blocks,
 				args->blocksize);
@@ -250,7 +250,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t opcode;
 			uint16_t major;
 			uint16_t minor;
-		}*args = (struct XHMEDIUMCHANGED_args *) stack;
+		}*args = (struct XHMEDIUMCHANGED_args *) &stack;
 
 		return xhdi_medium_changed(args->major, args->minor);
 	}
@@ -262,7 +262,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t opcode;
 			uint16_t subopcode;
 			void *data;
-		}*args = (struct XHMINTINFO_args *) stack;
+		}*args = (struct XHMINTINFO_args *) &stack;
 
 		return xhdi_mint_info(args->subopcode, args->data);
 	}
@@ -274,7 +274,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t opcode;
 			uint16_t which;
 			uint32_t limit;
-		}*args = (struct XHDOSLIMITS_args *) stack;
+		}*args = (struct XHDOSLIMITS_args *) &stack;
 
 		return xhdi_dos_limits(args->which, args->limit);
 	}
@@ -287,7 +287,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t major;
 			uint16_t minor;
 			uint32_t *ms;
-		}*args = (struct XHLASTACCESS_args *) stack;
+		}*args = (struct XHLASTACCESS_args *) &stack;
 
 		return xhdi_last_access(args->major, args->minor, args->ms);
 	}
@@ -299,7 +299,7 @@ uint32_t xhdi_call(uint16_t *stack)
 			uint16_t opcode;
 			uint16_t major;
 			uint16_t minor;
-		}*args = (struct XHREACCESS_args *) stack;
+		}*args = (struct XHREACCESS_args *) &stack;
 
 		return xhdi_reaccess(args->major, args->minor);
 	}