constify simon engine; turned global var vc_get_out_of_code into a member of class SimonEngine

svn-id: r16106

5 files changed, 90 insertions, 91 deletions

diff --git a/simon/debug.cpp b/simon/debug.cpp
index 67f8be31a8..071146aa30 100644
--- a/simon/debug.cpp
+++ b/simon/debug.cpp
@@ -169,7 +169,7 @@ void SimonEngine::dumpSubroutines() {
 	}
 }
 
-void SimonEngine::dump_video_script(byte *src, bool one_opcode_only) {
+void SimonEngine::dump_video_script(const byte *src, bool one_opcode_only) {
 	uint opcode;
 	const char *str, *strn;
 
@@ -233,43 +233,43 @@ void SimonEngine::dump_video_script(byte *src, bool one_opcode_only) {
 	} while (!one_opcode_only);
 }
 
-void SimonEngine::dump_vga_file(byte *vga) {
+void SimonEngine::dump_vga_file(const byte *vga) {
 	{
-		byte *pp;
-		byte *p;
+		const byte *pp;
+		const byte *p;
 		int count;
 
 		pp = vga;
-		p = pp + READ_BE_UINT16(&((VgaFile1Header *) pp)->hdr2_start);
-		count = READ_BE_UINT16(&((VgaFile1Header2 *) p)->id_count);
-		p = pp + READ_BE_UINT16(&((VgaFile1Header2 *) p)->id_table);
+		p = pp + READ_BE_UINT16(&((const VgaFile1Header *) pp)->hdr2_start);
+		count = READ_BE_UINT16(&((const VgaFile1Header2 *) p)->id_count);
+		p = pp + READ_BE_UINT16(&((const VgaFile1Header2 *) p)->id_table);
 		while (--count >= 0) {
-			int id = READ_BE_UINT16(&((VgaFile1Struct0x6 *) p)->id);
+			int id = READ_BE_UINT16(&((const VgaFile1Struct0x6 *) p)->id);
 
-			dump_vga_script_always(vga + READ_BE_UINT16(&((VgaFile1Struct0x6 *) p)->script_offs), id / 100, id);
+			dump_vga_script_always(vga + READ_BE_UINT16(&((const VgaFile1Struct0x6 *) p)->script_offs), id / 100, id);
 			p += sizeof(VgaFile1Struct0x6);
 		}
 	}
 
 	{
-		byte *bb, *b;
+		const byte *bb, *b;
 		int c;
 
 		bb = vga;
-		b = bb + READ_BE_UINT16(&((VgaFile1Header *) bb)->hdr2_start);
-		c = READ_BE_UINT16(&((VgaFile1Header2 *) b)->unk1);
-		b = bb + READ_BE_UINT16(&((VgaFile1Header2 *) b)->unk2_offs);
+		b = bb + READ_BE_UINT16(&((const VgaFile1Header *) bb)->hdr2_start);
+		c = READ_BE_UINT16(&((const VgaFile1Header2 *) b)->unk1);
+		b = bb + READ_BE_UINT16(&((const VgaFile1Header2 *) b)->unk2_offs);
 
 		while (--c >= 0) {
-			int id = READ_BE_UINT16(&((VgaFile1Struct0x8 *) b)->id);
+			int id = READ_BE_UINT16(&((const VgaFile1Struct0x8 *) b)->id);
 
-			dump_vga_script_always(vga + READ_BE_UINT16(&((VgaFile1Struct0x8 *) b)->script_offs), id / 100, id);
+			dump_vga_script_always(vga + READ_BE_UINT16(&((const VgaFile1Struct0x8 *) b)->script_offs), id / 100, id);
 			b += sizeof(VgaFile1Struct0x8);
 		}
 	}
 }
 
-const byte bmp_hdr[] = {
+static const byte bmp_hdr[] = {
 	0x42, 0x4D,
 	0x9E, 0x14, 0x00, 0x00,				/* offset 2, file size */
 	0x00, 0x00, 0x00, 0x00,
@@ -323,7 +323,7 @@ void dump_bmp(const char *filename, int w, int h, const byte *bytes, const uint3
 	fclose(out);
 }
 
-void dump_bitmap(const char *filename, byte *offs, int w, int h, int flags, const byte *palette,
+static void dump_bitmap(const char *filename, const byte *offs, int w, int h, int flags, const byte *palette,
 								 byte base)
 {
 	/* allocate */
@@ -351,7 +351,7 @@ void dump_bitmap(const char *filename, byte *offs, int w, int h, int flags, cons
 	free(b);
 }
 
-void SimonEngine::dump_single_bitmap(int file, int image, byte *offs, int w, int h, byte base) {
+void SimonEngine::dump_single_bitmap(int file, int image, const byte *offs, int w, int h, byte base) {
 	char buf[40];
 #if !defined(__PALM_OS__) && !defined(__DC__)
 	struct stat statbuf;
@@ -390,11 +390,11 @@ void pal_load(byte *pal, const byte *vga1, int a, int b) {
 	} while (--num);
 }
 
-void SimonEngine::dump_vga_bitmaps(byte *vga, byte *vga1, int res) {
+void SimonEngine::dump_vga_bitmaps(const byte *vga, byte *vga1, int res) {
 
 	int i;
 	uint32 offs;
-	byte *p2;
+	const byte *p2;
 	byte pal[768];
 
 	{
@@ -411,14 +411,14 @@ void SimonEngine::dump_vga_bitmaps(byte *vga, byte *vga1, int res) {
 
 	for(i = 1; ; i++) {
 		p2 = vga + i * 8;
-		offs = TO_BE_32(*(uint32 *)p2);
+		offs = READ_BE_UINT32(p2);
 
 		/* try to detect end of images.
 		 * assume the end when offset >= 200kb */
 		if (offs >= 200*1024)
 			return;
 		
-		width = TO_BE_16(*(uint16 *)(p2 + 6));
+		width = READ_BE_UINT16(p2 + 6);
 		height = p2[5];
 		flags = p2[4];
 
@@ -439,14 +439,14 @@ void SimonEngine::dump_vga_bitmaps(byte *vga, byte *vga1, int res) {
 	}
 }
 
-void SimonEngine::dump_vga_script_always(byte *ptr, uint res, uint sprite_id) {
+void SimonEngine::dump_vga_script_always(const byte *ptr, uint res, uint sprite_id) {
 	fprintf(_dump_file, "; address=%x, vgafile=%d  vgasprite=%d\n",
 					ptr - _vga_buffer_pointers[res].vgaFile1, res, sprite_id);
 	dump_video_script(ptr, false);
 	fprintf(_dump_file, "; end\n");
 }
 
-void SimonEngine::dump_vga_script(byte *ptr, uint res, uint sprite_id) {
+void SimonEngine::dump_vga_script(const byte *ptr, uint res, uint sprite_id) {
 	dump_vga_script_always(ptr, res, sprite_id);
 }
 
diff --git a/simon/simon.cpp b/simon/simon.cpp
index ca57171802..f6f6cd3da2 100644
--- a/simon/simon.cpp
+++ b/simon/simon.cpp
@@ -263,6 +263,7 @@ SimonEngine::SimonEngine(GameDetector *detector, OSystem *syst)
 	: Engine(syst), midi(syst) {
 
 	_vc_ptr = 0;
+	_vc_get_out_of_code = 0;
 	_game_offsets_ptr = 0;
 	
 	const SimonGameSettings *g = simon_settings;
@@ -2420,7 +2421,7 @@ void SimonEngine::set_video_mode_internal(uint mode, uint vga_res_id) {
 	VgaPointersEntry *vpe;
 	byte *bb, *b;
 	uint16 c;
-	byte *vc_ptr_org;
+	const byte *vc_ptr_org;
 
 	_video_palette_mode = mode;
 	_lock_word |= 0x20;
@@ -2561,7 +2562,7 @@ void SimonEngine::expire_vga_timers() {
 		if (!--vte->delay) {
 			uint16 cur_file = vte->cur_vga_file;
 			uint16 cur_unk = vte->sprite_id;
-			byte *script_ptr = vte->script_pointer;
+			const byte *script_ptr = vte->script_pointer;
 
 			_next_vga_timer_to_process = vte + 1;
 			delete_vga_timer(vte);
@@ -2601,7 +2602,7 @@ void SimonEngine::scroll_timeout() {
 	add_vga_timer(6, NULL, 0, 0);
 }
 
-void SimonEngine::vc_resume_sprite(byte *code_ptr, uint16 cur_file, uint16 cur_sprite) {
+void SimonEngine::vc_resume_sprite(const byte *code_ptr, uint16 cur_file, uint16 cur_sprite) {
 	VgaPointersEntry *vpe;
 
 	_vga_cur_sprite_id = cur_sprite;
@@ -2618,7 +2619,7 @@ void SimonEngine::vc_resume_sprite(byte *code_ptr, uint16 cur_file, uint16 cur_s
 	run_vga_script();
 }
 
-void SimonEngine::add_vga_timer(uint num, byte *code_ptr, uint cur_sprite, uint cur_file) {
+void SimonEngine::add_vga_timer(uint num, const byte *code_ptr, uint cur_sprite, uint cur_file) {
 	VgaTimerEntry *vte;
 
 	// When Simon talks to the Golum about stew in French version of
@@ -2711,7 +2712,7 @@ void SimonEngine::skip_speech() {
 void SimonEngine::timer_vga_sprites() {
 	VgaSprite *vsp;
 	VgaPointersEntry *vpe;
-	byte *vc_ptr_org = _vc_ptr;
+	const byte *vc_ptr_org = _vc_ptr;
 	uint16 params[5];							// parameters to vc_10
 
 	if (_video_var_9 == 2)
@@ -2743,7 +2744,7 @@ void SimonEngine::timer_vga_sprites() {
 			params[4] = READ_BE_UINT16(&vsp->unk4);
 		}
 
-		_vc_ptr = (byte *)params;
+		_vc_ptr = (const byte *)params;
 		vc_10_draw();
 
 		vsp++;
@@ -2757,7 +2758,8 @@ void SimonEngine::timer_vga_sprites() {
 }
 
 void SimonEngine::timer_vga_sprites_helper() {
-	byte *dst = dx_lock_2(), *src;
+	byte *dst = dx_lock_2();
+	const byte *src;
 	uint x;
 
 	if (_vga_var3 < 0) {
@@ -2774,7 +2776,7 @@ void SimonEngine::timer_vga_sprites_helper() {
 	}
 
 	src = _vga_var7 + x * 4;
-	decodeStripA(dst, src + READ_BE_UINT32(&*((uint32 *)src)), _vga_var5);
+	decodeStripA(dst, src + READ_BE_UINT32(src), _vga_var5);
 
 	dx_unlock_2();
 
@@ -2793,7 +2795,7 @@ void SimonEngine::timer_vga_sprites_helper() {
 void SimonEngine::timer_vga_sprites_2() {
 	VgaSprite *vsp;
 	VgaPointersEntry *vpe;
-	byte *vc_ptr_org = _vc_ptr;
+	const byte *vc_ptr_org = _vc_ptr;
 	uint16 params[5];							// parameters to vc_10_draw
 
 	if (_video_var_9 == 2)
@@ -2817,7 +2819,7 @@ void SimonEngine::timer_vga_sprites_2() {
 		params[2] = READ_BE_UINT16(&vsp->x);
 		params[3] = READ_BE_UINT16(&vsp->y);
 		params[4] = READ_BE_UINT16(&vsp->unk4);
-		_vc_ptr = (byte *)params;
+		_vc_ptr = (const byte *)params;
 		vc_10_draw();
 
 		vsp++;
@@ -3009,7 +3011,7 @@ uint SimonEngine::itemPtrToID(Item *id) {
 }
 
 void SimonEngine::o_pathfind(int x, int y, uint var_1, uint var_2) {
-	uint16 *p;
+	const uint16 *p;
 	uint i, j;
 	uint prev_i;
 	uint x_diff, y_diff;
@@ -3021,7 +3023,7 @@ void SimonEngine::o_pathfind(int x, int y, uint var_1, uint var_2) {
 
 	prev_i = 21 - _variableArray[12];
 	for (i = 20; i != 0; --i) {
-		p = (uint16 *)_pathfind_array[20 - i];
+		p = (const uint16 *)_pathfind_array[20 - i];
 		if (!p)
 			continue;
 		for (j = 0; READ_BE_UINT16(&p[0]) != 999; j++, p += 2) {	// 0xE703 = byteswapped 999
diff --git a/simon/simon.h b/simon/simon.h
index b27781abe2..14f6731f82 100644
--- a/simon/simon.h
+++ b/simon/simon.h
@@ -87,7 +87,7 @@ struct VgaSprite {
 
 struct VgaSleepStruct {
 	uint16 ident;
-	byte *code_ptr;
+	const byte *code_ptr;
 	uint16 sprite_id;
 	uint16 cur_vga_file;
 	VgaSleepStruct() { memset(this, 0, sizeof(*this)); }
@@ -95,7 +95,7 @@ struct VgaSleepStruct {
 
 struct VgaTimerEntry {
 	uint16 delay;
-	byte *script_pointer;
+	const byte *script_pointer;
 	uint16 sprite_id;
 	uint16 cur_vga_file;
 	VgaTimerEntry() { memset(this, 0, sizeof(*this)); }
@@ -112,7 +112,9 @@ class SimonEngine : public Engine {
 protected:
 	void playSting(uint a);
 	
-	byte *_vc_ptr;								/* video code ptr */
+	const byte *_vc_ptr;								/* video code ptr */
+	uint16 _vc_get_out_of_code;
+
 
 	uint32 *_game_offsets_ptr;
 
@@ -211,7 +213,7 @@ protected:
 	int16 _script_unk_1;
 	bool _vga_var6;
 	int _x_scroll, _vga_var1, _vga_var2, _vga_var3, _vga_var5;
-	byte *_vga_var7;
+	const byte *_vga_var7;
 	byte _vga_var8;
 
 	int16 _script_cond_a, _script_cond_b, _script_cond_c;
@@ -323,7 +325,7 @@ protected:
 	VgaSprite _vga_sprites[180];
 	VgaSleepStruct _vga_sleep_structs[30];
 
-	uint16 *_pathfind_array[20];
+	const uint16 *_pathfind_array[20];
 
 	uint8 _palette_backup[1024];
 	uint8 _palette[1024];
@@ -371,7 +373,7 @@ protected:
 
 	Common::RandomSource _rnd;
 
-	byte *_vc_10_base_ptr_old;
+	const byte *_vc_10_base_ptr_old;
 	byte _hebrew_char_widths[32];
 
 public:
@@ -695,7 +697,7 @@ public:
 
 protected:
 	void delete_vga_timer(VgaTimerEntry * vte);
-	void vc_resume_sprite(byte *code_ptr, uint16 cur_file, uint16 cur_sprite);
+	void vc_resume_sprite(const byte *code_ptr, uint16 cur_file, uint16 cur_sprite);
 	int vc_read_var_or_word();
 	uint vc_read_next_word();
 	uint vc_read_next_byte();
@@ -707,7 +709,7 @@ protected:
 	bool itemIsParentOf(uint16 a, uint16 b);
 	bool vc_maybe_skip_proc_1(uint16 a, int16 b);
 
-	void add_vga_timer(uint num, byte *code_ptr, uint cur_sprite, uint cur_file);
+	void add_vga_timer(uint num, const byte *code_ptr, uint cur_sprite, uint cur_file);
 	VgaSprite *find_cur_sprite();
 	void vc_set_bit_to(uint bit, bool value);
 
@@ -755,12 +757,12 @@ protected:
 	void dx_clear_surfaces(uint num_lines);
 	void dx_update_screen_and_palette();
 
-	void dump_video_script(byte *src, bool one_opcode_only);
-	void dump_vga_file(byte *vga);
-	void dump_vga_script(byte *ptr, uint res, uint sprite_id);
-	void dump_vga_script_always(byte *ptr, uint res, uint sprite_id);
-	void dump_vga_bitmaps(byte *vga, byte *vga1, int res);
-	void dump_single_bitmap(int file, int image, byte *offs, int w, int h, byte base);
+	void dump_video_script(const byte *src, bool one_opcode_only);
+	void dump_vga_file(const byte *vga);
+	void dump_vga_script(const byte *ptr, uint res, uint sprite_id);
+	void dump_vga_script_always(const byte *ptr, uint res, uint sprite_id);
+	void dump_vga_bitmaps(const byte *vga, byte *vga1, int res);
+	void dump_single_bitmap(int file, int image, const byte *offs, int w, int h, byte base);
 
 	void dx_clear_attached_from_top(uint lines);
 	void dx_copy_from_attached_to_2(uint x, uint y, uint w, uint h);
@@ -773,8 +775,8 @@ protected:
 	void quick_load_or_save();
 	void shutdown();
 
-	byte *vc_10_depack_swap(byte *src, uint w, uint h);
-	byte *vc_10_no_depack_swap(byte *src, uint w, uint h);
+	byte *vc_10_depack_swap(const byte *src, uint w, uint h);
+	byte *vc_10_no_depack_swap(const byte *src, uint w, uint h);
 
 	Item *getNextItemPtrStrange();
 
@@ -796,7 +798,7 @@ protected:
 	void o_190_helper(uint i);
 	void timer_vga_sprites_helper();
 
-	void decodeStripA(byte *dst, byte *src, int height);
+	void decodeStripA(byte *dst, const byte *src, int height);
 	void scroll_timeout();
 	void hitarea_stuff_helper_2();
 	void realizePalette();
diff --git a/simon/vga.cpp b/simon/vga.cpp
index 168e65489b..5dbb3f934c 100644
--- a/simon/vga.cpp
+++ b/simon/vga.cpp
@@ -28,7 +28,6 @@
 namespace Simon {
 
 typedef void (SimonEngine::*VgaOpcodeProc) ();
-static uint16 vc_get_out_of_code = 0;
 
 // Opcode tables
 static const VgaOpcodeProc vga_opcode_table[] = {
@@ -115,7 +114,7 @@ void SimonEngine::run_vga_script() {
 		uint opcode;
 
 		if (_continous_vgascript) {
-			if (_vc_ptr != (byte *)&vc_get_out_of_code) {
+			if (_vc_ptr != (const byte *)&_vc_get_out_of_code) {
 				fprintf(_dump_file, "%.5d %.5X: %5d %4d ", _vga_tick_counter, _vc_ptr - _cur_vga_file_1, _vga_cur_sprite_id, _vga_cur_file_id);
 				dump_video_script(_vc_ptr, true);
 			}
@@ -223,7 +222,8 @@ void SimonEngine::vc_2_call() {
 	uint num;
 	uint res;
 	byte *old_file_1, *old_file_2;
-	byte *b, *bb, *vc_ptr_org;
+	byte *b, *bb;
+	const byte *vc_ptr_org;
 
 	num = vc_read_var_or_word();
 
@@ -392,7 +392,7 @@ void SimonEngine::vc_9_skip_if_unk3_is() {
 
 byte *vc_10_depack_column(VC10_state * vs) {
 	int8 a = vs->depack_cont;
-	byte *src = vs->depack_src;
+	const byte *src = vs->depack_src;
 	byte *dst = vs->depack_dest;
 	byte dh = vs->dh;
 	byte color;
@@ -440,7 +440,7 @@ void vc_10_skip_cols(VC10_state *vs) {
 	}
 }
 
-byte *SimonEngine::vc_10_depack_swap(byte *src, uint w, uint h) {
+byte *SimonEngine::vc_10_depack_swap(const byte *src, uint w, uint h) {
 	w <<= 3;
 
 	{
@@ -513,7 +513,7 @@ byte *SimonEngine::vc_10_depack_swap(byte *src, uint w, uint h) {
 	return _video_buf_1;
 }
 
-byte *SimonEngine::vc_10_no_depack_swap(byte *src, uint w, uint h) {
+byte *SimonEngine::vc_10_no_depack_swap(const byte *src, uint w, uint h) {
 	if (src == _vc_10_base_ptr_old)
 		return _video_buf_1;
 
@@ -544,7 +544,7 @@ static uint16 _video_windows[128] = {
 };
 
 /* simon2 specific */
-void SimonEngine::decodeStripA(byte *dst, byte *src, int height) {
+void SimonEngine::decodeStripA(byte *dst, const byte *src, int height) {
 	const uint pitch = _dx_surface_pitch;
 	int8 reps = (int8)0x80;
 	byte color;
@@ -642,7 +642,8 @@ void SimonEngine::vc_10_draw() {
 	}
 
 	if (_game & GF_SIMON2 && width >= 21) {
-		byte *src, *dst;
+		const byte *src;
+		byte *dst;
 		uint w;
 
 		_vga_var1 = width * 2 - 40;
@@ -794,7 +795,8 @@ void SimonEngine::vc_10_draw() {
 
 		/* vc_10_helper_5 */
 	} else if (_lock_word & 0x20 && state.base_color == 0 || state.base_color == 0xC0) {
-		byte *src, *dst;
+		const byte *src;
+		byte *dst;
 		uint h, i;
 
 		if (!(state.e & 8)) {
@@ -962,7 +964,8 @@ void SimonEngine::vc_10_draw() {
 			}
 			/* vc_10_helper_6 */
 		} else {
-			byte *src, *dst;
+			const byte *src;
+			byte *dst;
 			uint count;
 
 			src = state.depack_src + (width * state.y_skip) * 8;
@@ -1025,7 +1028,7 @@ void SimonEngine::vc_12_delay() {
 		num += VGA_DELAY_BASE;
 
 	add_vga_timer(num, _vc_ptr, _vga_cur_sprite_id, _vga_cur_file_id);
-	_vc_ptr = (byte *)&vc_get_out_of_code;
+	_vc_ptr = (byte *)&_vc_get_out_of_code;
 }
 
 void SimonEngine::vc_13_set_sprite_offset_x() {
@@ -1071,12 +1074,12 @@ void SimonEngine::vc_16_sleep_on_id() {
 	vfs->sprite_id = _vga_cur_sprite_id;
 	vfs->cur_vga_file = _vga_cur_file_id;
 
-	_vc_ptr = (byte *)&vc_get_out_of_code;
+	_vc_ptr = (byte *)&_vc_get_out_of_code;
 }
 
 void SimonEngine::vc_17_set_pathfind_item() {
 	uint a = vc_read_next_word();
-	_pathfind_array[a - 1] = (uint16 *)_vc_ptr;
+	_pathfind_array[a - 1] = (const uint16 *)_vc_ptr;
 	while (READ_BE_UINT16(_vc_ptr) != 999)
 		_vc_ptr += 4;
 	_vc_ptr += 2;
@@ -1095,36 +1098,28 @@ void SimonEngine::vc_19_chain_to_script() {
 
 /* helper routines */
 
-/* write unaligned 16-bit */
-static void write_16_le(void *p, uint16 a) {
-	((byte *)p)[0] = (byte)(a);
-	((byte *)p)[1] = (byte)(a >> 8);
-}
-
-/* read unaligned 16-bit */
-static uint16 read_16_le(void *p) {
-	return ((byte *)p)[0] | (((byte *)p)[1] << 8);
-}
-
-/* FIXME: unaligned access */
 void SimonEngine::vc_20_set_code_word() {
+	/* FIXME: This pücode is somewhat strange: it first reads a BE word from 
+	 * the script (advancing the script pointer in doing so); then it writes
+	 * back the same word, this time as LE, into the script.
+	 */
 	uint16 a = vc_read_next_word();
-	write_16_le(_vc_ptr, a);
+	WRITE_LE_UINT16(const_cast<byte *>(_vc_ptr), a);
 	_vc_ptr += 2;
 }
 
-/* FIXME: unaligned access */
 void SimonEngine::vc_21_jump_if_code_word() {
 	int16 a = vc_read_next_word();
-	byte *tmp = _vc_ptr + a;
+	const byte *tmp = _vc_ptr + a;
 	if (_game & GF_SIMON2)
 		tmp += 3;
 	else
 		tmp += 4;
 
-	uint16 val = read_16_le(tmp);
+	uint16 val = READ_LE_UINT16(tmp);
 	if (val != 0) {
-		write_16_le(tmp, val - 1);
+		// Decrement counter
+		WRITE_LE_UINT16(const_cast<byte *>(tmp), val - 1);
 		_vc_ptr = tmp + 2;
 	}
 }
@@ -1210,7 +1205,7 @@ void SimonEngine::vc_25_halt_sprite() {
 		memcpy(vsp, vsp + 1, sizeof(VgaSprite));
 		vsp++;
 	}
-	_vc_ptr = (byte *)&vc_get_out_of_code;
+	_vc_ptr = (byte *)&_vc_get_out_of_code;
 	_vga_sprite_changed++;
 }
 
@@ -1456,7 +1451,7 @@ void SimonEngine::vc_42_delay_if_not_eq() {
 	if (val != vc_read_next_word()) {
 
 		add_vga_timer(_vga_base_delay + 1, _vc_ptr - 4, _vga_cur_sprite_id, _vga_cur_file_id);
-		_vc_ptr = (byte *)&vc_get_out_of_code;
+		_vc_ptr = (byte *)&_vc_get_out_of_code;
 	}
 }
 
@@ -1493,7 +1488,7 @@ void SimonEngine::vc_48() {
 	uint a = (uint16)_variableArray[12];
 	uint b = (uint16)_variableArray[13];
 	int c = _variableArray[14];
-	uint16 *p = _pathfind_array[a - 1];
+	const uint16 *p = _pathfind_array[a - 1];
 	int step;
 	int y1, y2;
 	int16 *vp;
@@ -1595,7 +1590,7 @@ void SimonEngine::vc_56_delay() {
 		uint num = vc_read_var_or_word() * _vga_base_delay;
 
 		add_vga_timer(num + VGA_DELAY_BASE, _vc_ptr, _vga_cur_sprite_id, _vga_cur_file_id);
-		_vc_ptr = (byte *)&vc_get_out_of_code;
+		_vc_ptr = (byte *)&_vc_get_out_of_code;
 	}
 }
 
@@ -1617,7 +1612,7 @@ void SimonEngine::vc_59() {
 void SimonEngine::vc_58() {
 	uint sprite = _vga_cur_sprite_id;
 	uint file = _vga_cur_file_id;
-	byte *vc_ptr_org;
+	const byte *vc_ptr_org;
 	uint16 tmp;
 
 	_vga_cur_file_id = vc_read_next_word();
@@ -1643,7 +1638,7 @@ void SimonEngine::vc_kill_sprite(uint file, uint sprite) {
 	VgaSleepStruct *vfs;
 	VgaSprite *vsp;
 	VgaTimerEntry *vte;
-	byte *vc_ptr_org;
+	const byte *vc_ptr_org;
 
 	old_sprite_id = _vga_cur_sprite_id;
 	old_cur_file_id = _vga_cur_file_id;
@@ -1736,7 +1731,7 @@ void SimonEngine::vc_62_palette_thing() {
 			uint16 params[5];						/* parameters to vc_10_draw */
 			VgaSprite *vsp;
 			VgaPointersEntry *vpe;
-			byte *vc_ptr_org = _vc_ptr;
+			const byte *vc_ptr_org = _vc_ptr;
 
 			vsp = _vga_sprites;
 			while (vsp->id != 0) {
diff --git a/simon/vga.h b/simon/vga.h
index e3e01db7a2..1bcb8a2207 100644
--- a/simon/vga.h
+++ b/simon/vga.h
@@ -73,7 +73,7 @@ struct VC10_state {
 
 	byte dl, dh;
 
-	byte *depack_src;
+	const byte *depack_src;
 	int8 depack_cont;
 
 	byte depack_dest[200];