[Scummvm-devel] Problem with alignement with GCC

[Lionel Ulmer]

Hi all,

I finally found out why ScummVM was not working properly on my iPAQ. The
fault lies in GCC's way of handling the '#pragma pack' directive.

I did some tests with the following test file :

#pragma pack (1)
struct toto {
  char a;
  int b;
};
#pragma pack ()
struct toti {
  char a;
  int b;
};
	
void main() {
  printf("%d %d\n", sizeof(struct toto),sizeof(struct toti));
}

The results are :

 5 8 with gcc 2.95.2 (built by myself on x86)
 8 8 with gcc 2.95.4 (the Debian ARM package)

So to be 100 % sure to have the structure packed on any version of GCC, I
did the following change (see patch included against latest CVS version).

Anyway, there is also a typo in scummvm.cpp (also fixed by the patch :-) ) :

   {"tentacle", "Day Of The Tenctacle", GID_TENTACLE, 6, 4, 2},
   {"dottdemo", "Day Of The Tenctacle (Demo)", GID_TENTACLE, 6, 3, 2},
                              ^^^

Now, I am going to see why the sound does not work on the iPAQ !

                            Lionel

-- 
		 Lionel Ulmer - http://www.bbrox.org/
-------------- next part --------------
Index: scummsys.h
===================================================================
RCS file: /cvsroot/scummvm/scummvm/scummsys.h,v
retrieving revision 1.11
diff -u -r1.11 scummsys.h
--- scummsys.h	2001/11/07 18:17:20	1.11
+++ scummsys.h	2001/11/10 10:35:09
@@ -53,6 +53,7 @@
 
 #define START_PACK_STRUCTS pack (push,1)
 #define END_PACK_STRUCTS   pack(pop)
+#define GCC_PACK
 
 #elif defined(UNIX)
 
@@ -74,10 +75,6 @@
 
 #define FORCEINLINE inline
 
-#if defined(__GNUC__)
-#define NORETURN __attribute__((__noreturn__)) 
-#else
-#endif
 #define CDECL 
 
 typedef unsigned char byte;
@@ -89,13 +86,21 @@
 typedef signed short int16;
 typedef signed long int32;
 
+#if defined(__GNUC__)
+#define START_PACK_STRUCTS
+#define END_PACK_STRUCTS
+#define GCC_PACK __attribute__((packed))
+#define NORETURN __attribute__((__noreturn__)) 
+#else
 #define START_PACK_STRUCTS pack (1)
 #define END_PACK_STRUCTS   pack ()
+#define GCC_PACK
+#define NORETURN
+#endif
 
 #else
 #error No system type defined
 #endif
-
 
 #if defined(SCUMM_LITTLE_ENDIAN)
 
Index: scumm.h
===================================================================
RCS file: /cvsroot/scummvm/scummvm/scumm.h,v
retrieving revision 1.22
diff -u -r1.22 scumm.h
--- scumm.h	2001/11/09 18:54:14	1.22
+++ scumm.h	2001/11/10 10:35:11
@@ -34,12 +34,12 @@
 	
 struct Point {
 	int x,y;
-};
+} GCC_PACK;
 
 struct AdjustBoxResult {
 	int16 x,y;
 	uint16 dist;
-};
+} GCC_PACK;
 
 #define SIZEOF_BOX 20
 struct Box { /* file format */
@@ -50,7 +50,7 @@
 	byte mask;
 	byte flags;
 	uint16 scale;
-};
+} GCC_PACK;
 
 struct VerbSlot {
 	int16 x,y;
@@ -64,7 +64,7 @@
 	bool center;
 	uint8 field_1B;
 	uint16 imgindex;
-};
+} GCC_PACK;
 
 struct VirtScreen {
 	int number;
@@ -77,7 +77,7 @@
 	uint16 xstart;
 	byte tdirty[40];
 	byte bdirty[40];
-};
+} GCC_PACK;
 
 struct ActorWalkData {
 	int16 destx,desty;
@@ -88,7 +88,7 @@
 	int16 x,y,newx,newy;
 	int32 XYFactor, YXFactor;
 	uint16 xfrac,yfrac;
-};
+} GCC_PACK;
 
 struct CostumeData {
 	uint16 hdr;
@@ -96,13 +96,13 @@
 	byte animCounter2;
 	byte x_1;
 	uint16 a[16], b[16], c[16], d[16];
-};
+} GCC_PACK;
 
 struct MouseCursor {
 	int8 hotspot_x, hotspot_y;
 	byte colors[4];
 	byte data[32];
-};
+} GCC_PACK;
 
 struct ScriptSlot {
 	uint32 offs;
@@ -114,17 +114,17 @@
 	byte unk1,unk2,freezeCount,didexec;
 	byte cutsceneOverride;
 	byte unk5;
-};
+} GCC_PACK;
 
 struct NestedScript {
 	uint16 number;
 	uint8 type;
 	uint8 slot;
-};
+} GCC_PACK;
 
 struct ResHeader {
 	uint32 size;
-};
+} GCC_PACK;
 
 class ObjectData {
 public:
@@ -142,13 +142,13 @@
 	byte ownerstate;
 	byte fl_object_index;
 	byte unk_3;
-};
+} GCC_PACK;
 
 struct RoomHeader {
 	uint32 tag, size;
 	uint16 width,height;
 	uint16 numObjects;
-};
+} GCC_PACK;
 
 struct CodeHeader {
 	uint32 id;
@@ -174,7 +174,7 @@
 			byte actordir;
 		} v6;
 	};
-};
+} GCC_PACK;
 
 struct ImageHeader { /* file format */
 	uint32 id;
@@ -187,7 +187,7 @@
 	struct {
 		int16 x,y;
 	} hotspot[15];
-};
+} GCC_PACK;
 
 #pragma END_PACK_STRUCTS
 
@@ -1668,4 +1668,4 @@
 void blit(byte *dst, byte *src, int w, int h);
 byte *findResource(uint32 id, byte *searchin, int index);
 void playSfxSound(void *sound, uint32 size, uint rate);
-bool isSfxFinished();
\ No newline at end of file
+bool isSfxFinished();
Index: scummvm.cpp
===================================================================
RCS file: /cvsroot/scummvm/scummvm/scummvm.cpp,v
retrieving revision 1.22
diff -u -r1.22 scummvm.cpp
--- scummvm.cpp	2001/11/09 18:54:15	1.22
+++ scummvm.cpp	2001/11/10 10:35:11
@@ -415,8 +415,8 @@
 	{"monkey2", "Monkey Island 2: LeChuck's revenge", GID_MONKEY2, 5, 2, 2},
 	{"atlantis", "Indiana Jones 4 and the Fate of Atlantis", GID_INDY4, 5, 5, 0},
 	{"playfate", "Indiana Jones 4 and the Fate of Atlantis (Demo)", GID_INDY4, 5, 5, 0},
-	{"tentacle", "Day Of The Tenctacle", GID_TENTACLE, 6, 4, 2},
-	{"dottdemo", "Day Of The Tenctacle (Demo)", GID_TENTACLE, 6, 3, 2},
+	{"tentacle", "Day Of The Tentacle", GID_TENTACLE, 6, 4, 2},
+	{"dottdemo", "Day Of The Tentacle (Demo)", GID_TENTACLE, 6, 3, 2},
 	{"samnmax", "Sam & Max", GID_SAMNMAX, 6, 4, 2},
 	{"snmdemo", "Sam & Max (Demo)", GID_SAMNMAX, 6, 3, 0},
 	{NULL,NULL}