diff --git a/demos/shooter/demo.c b/demos/shooter/demo.c
index bc07b80e9e..ea665664a3 100644
--- a/demos/shooter/demo.c
+++ b/demos/shooter/demo.c
@@ -91,7 +91,7 @@ int main(int argc, char *argv[])
       install_joystick(JOY_TYPE_NONE);
    }
 
-   if (set_gfx_mode(GFX_AUTODETECT, 320, 200, 0, 0) != 0) {
+   if (set_gfx_mode(GFX_AUTODETECT, 320, 200, 0, 0) != 0) {   //GFX_AUTODETECT
       if (set_gfx_mode(GFX_SAFE, 320, 200, 0, 0) != 0) {
          set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
          allegro_message("Unable to set any graphic mode\n%s\n",
diff --git a/src/file.c b/src/file.c
index c89024c14e..633478d86d 100644
--- a/src/file.c
+++ b/src/file.c
@@ -2065,7 +2065,7 @@ PACKFILE *pack_fopen_chunk(PACKFILE *f, int pack)
 	       return NULL;
 	    }
 	    _al_sane_strncpy(chunk->normal.passdata, f->normal.passdata, strlen(f->normal.passdata)+1);
-	    chunk->normal.passpos = chunk->normal.passdata + (long)f->normal.passpos - (long)f->normal.passdata;
+	    chunk->normal.passpos = chunk->normal.passdata + (ULONG_PTR)f->normal.passpos - (ULONG_PTR)f->normal.passdata;  //64bit   long
 	    f->normal.passpos = f->normal.passdata;
 	 }
 	 chunk->normal.flags |= PACKFILE_FLAG_OLD_CRYPT;
@@ -2188,7 +2188,7 @@ PACKFILE *pack_fclose_chunk(PACKFILE *f)
       }
 
       if ((f->normal.passpos) && (f->normal.flags & PACKFILE_FLAG_OLD_CRYPT))
-	 parent->normal.passpos = parent->normal.passdata + (long)f->normal.passpos - (long)f->normal.passdata;
+	 parent->normal.passpos = parent->normal.passdata + (ULONG_PTR)f->normal.passpos - (ULONG_PTR)f->normal.passdata;  //64bit  long
 
       free_packfile(f);
    }
diff --git a/src/fsel.c b/src/fsel.c
index 96fd796bc2..024d8823c3 100644
--- a/src/fsel.c
+++ b/src/fsel.c
@@ -933,7 +933,7 @@ int file_select_ex(AL_CONST char *message, char *path, AL_CONST char *ext, int s
    if (ugetc(get_filename(path))) {
       p = get_extension(path);
       if ((!ugetc(p)) && (ext) && (ugetc(ext)) && (!ustrpbrk(ext, uconvert_ascii(" ,;", tmp)))) {
-         size -= ((long)p - (long)path + ucwidth('.'));
+         size -= ((unsigned long long)p - (unsigned long long)path + ucwidth('.')); //64bit  long
          if (size >= uwidth_max(U_CURRENT) + ucwidth(0)) {  /* do not end with '.' */
             p += usetc(p, '.');
             ustrzcpy(p, size, ext);
diff --git a/src/glyph.c b/src/glyph.c
index b4ba535ceb..b92b6ba974 100644
--- a/src/glyph.c
+++ b/src/glyph.c
@@ -25,7 +25,7 @@
 #define DRAW_GLYPH(bits, size)                                               \
 {                                                                            \
    AL_CONST unsigned char *data = glyph->dat;                                \
-   unsigned long addr;                                                       \
+   unsigned long long addr;                                                       \
    int w = glyph->w;                                                         \
    int h = glyph->h;                                                         \
    int stride = (w+7)/8;                                                     \
@@ -183,7 +183,7 @@ void _linear_draw_glyph24(BITMAP *bmp, AL_CONST FONT_GLYPH *glyph, int x, int y,
  */
 void _linear_draw_glyph32(BITMAP *bmp, AL_CONST FONT_GLYPH *glyph, int x, int y, int color, int bg)
 {
-   DRAW_GLYPH(32, sizeof(int32_t));
+   DRAW_GLYPH(32, sizeof(int32_t)); //64bit int32_t
 }
 
 #endif
diff --git a/src/gsprite.c b/src/gsprite.c
index 1f0f606f3c..1cfd3c4c5b 100644
--- a/src/gsprite.c
+++ b/src/gsprite.c
@@ -139,7 +139,7 @@ void _soft_draw_gouraud_sprite(BITMAP *bmp, BITMAP *sprite, int x, int y, int c1
 	       addr = bmp_write_line(bmp, j) + x1*3;
 	       for (i=x1; i<x2; i++) {
 		  bmp_select(sprite);
-		  pixel = bmp_read24((unsigned long)(sprite->line[j-y] + (i-x)*3));
+		  pixel = bmp_read24((unsigned long long)(sprite->line[j-y] + (i-x)*3));  //64bit unsigned long
 		  bmp_select(bmp);
 		  if (pixel != MASK_COLOR_24) {
 		     pixel = _blender_func24(pixel, _blender_col_24, fixtoi(hc));
diff --git a/src/gui.c b/src/gui.c
index dfe96f6169..c18dce6390 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -571,7 +571,7 @@ static int obj_list_cmp(AL_CONST void *e1, AL_CONST void *e2)
  */
 static int cmp_tab(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
 {
-   int ret = (int)((AL_CONST unsigned long)d2 - (AL_CONST unsigned long)d1);
+   int ret = (int)((AL_CONST unsigned long long)d2 - (AL_CONST unsigned long long)d1);  //64bit unsigned long
 
    /* Wrap around if d2 is before d1 in the dialog array. */
    if (ret < 0)
@@ -587,7 +587,7 @@ static int cmp_tab(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
  */
 static int cmp_shift_tab(AL_CONST DIALOG *d1, AL_CONST DIALOG *d2)
 {
-   int ret = (int)((AL_CONST unsigned long)d1 - (AL_CONST unsigned long)d2);
+   int ret = (int)((AL_CONST unsigned long long)d1 - (AL_CONST unsigned long long)d2);  //64bit unsigned long
 
    /* Wrap around if d2 is after d1 in the dialog array. */
    if (ret < 0)
diff --git a/src/guiproc.c b/src/guiproc.c
index edd284a831..8acf28a975 100644
--- a/src/guiproc.c
+++ b/src/guiproc.c
@@ -1365,17 +1365,17 @@ int d_text_list_proc(int msg, DIALOG *d, int c)
 		  thisitem = (*(getfuncptr)d->dp)(i, NULL);
 		  failure = FALSE;
 
-		  if ((int)((unsigned long)d->dp3) < ustrlen(thisitem)) {
-		     for (a=0; a < (int)((unsigned long)d->dp3); a++) {
+		  if ((int)((unsigned long long)d->dp3) < ustrlen(thisitem)) {
+		     for (a=0; a < (int)((unsigned long long)d->dp3); a++) {   //64bit unsigned long
 			if (utolower(ugetat(thisitem, a)) != utolower(ugetat(selected, a))) {
 			   failure = TRUE;
 			   break;
 			}
 		     }
 
-		     if ((!failure) && (utolower(ugetat(thisitem, (int)(unsigned long)d->dp3)) == utolower(c))) {
+		     if ((!failure) && (utolower(ugetat(thisitem, (int)(unsigned long long)d->dp3)) == utolower(c))) {
 			d->d1 = i;
-			d->dp3 = (void *)((unsigned long)d->dp3 + 1);
+			d->dp3 = (void *)((unsigned long long)d->dp3 + 1);
 
 			if (sel) {
 			   for (i=0; i<listsize; i++)
diff --git a/src/unicode.c b/src/unicode.c
index cd34afd71f..238668e9f9 100644
--- a/src/unicode.c
+++ b/src/unicode.c
@@ -737,7 +737,7 @@ int uoffset(AL_CONST char *s, int index)
       }
    }
 
-   return (long)s - (long)orig;
+   return (long long)s - (long long)orig;
 }
 
 
@@ -1783,7 +1783,7 @@ int ustrsize(AL_CONST char *s)
       last = s;
    } while (ugetxc(&s) != 0);
 
-   return (long)last - (long)orig;
+   return (long long)last - (long long)orig;
 }
 
 
@@ -1800,7 +1800,7 @@ int ustrsizez(AL_CONST char *s)
    do {
    } while (ugetxc(&s) != 0);
 
-   return (long)s - (long)orig;
+   return (long long)s - (long long)orig;
 }
 
 
@@ -2313,7 +2313,7 @@ long ustrtol(AL_CONST char *s, char **endp, int base)
    ret = strtol(t, &myendp, base);
 
    if (endp)
-      *endp = (char *)s + uoffset(s, (long)myendp - (long)t);
+      *endp = (char *)s + uoffset(s, (long long)myendp - (long long)t);
 
    return ret;
 }
@@ -2337,7 +2337,7 @@ double ustrtod(AL_CONST char *s, char **endp)
    ret = strtod(t, &myendp);
 
    if (endp)
-      *endp = (char *)s + uoffset(s, (long)myendp - (long)t);
+      *endp = (char *)s + uoffset(s, (long long)myendp - (long long)t);
 
    return ret;
 }
@@ -2948,7 +2948,7 @@ static int decode_format_string(char *buf, STRING_ARG *string_arg, AL_CONST char
 
 	       case 'p':
 		  /* pointer */
-		  slen = sprint_hex(string_arg, &info, FALSE, (unsigned long)(va_arg(args, void *)));
+		  slen = sprint_hex(string_arg, &info, FALSE, (unsigned long long)(va_arg(args, void *)));
 		  NEXT_C();
 		  break;
 
diff --git a/src/win/gdi.c b/src/win/gdi.c
index c40c488c9a..d5aee98efd 100644
--- a/src/win/gdi.c
+++ b/src/win/gdi.c
@@ -198,7 +198,7 @@ static BYTE *get_dib_from_bitmap(BITMAP *bitmap)
    int bpp;
    int x, y;
    int pitch;
-   int col;
+   long col;
    BYTE *pixels;
    BYTE *src, *dst;
 
diff --git a/src/win/wddlock.c b/src/win/wddlock.c
index 91219be969..c4210f9240 100644
--- a/src/win/wddlock.c
+++ b/src/win/wddlock.c
@@ -165,7 +165,7 @@ void gfx_directx_lock(BITMAP *bmp)
       bmp->id |= BMP_ID_LOCKED;
 
       /* update the line array if our parent has moved */
-      pitch = (long)parent->line[1] - (long)parent->line[0];
+      pitch = (long long)parent->line[1] - (long long)parent->line[0];
       data = parent->line[0] +
              (bmp->y_ofs - parent->y_ofs) * pitch +
              (bmp->x_ofs - parent->x_ofs) * BYTES_PER_PIXEL(bitmap_color_depth(bmp));
@@ -263,7 +263,7 @@ void gfx_directx_autolock(BITMAP *bmp)
       }
 
       /* update the line array if our parent has moved */
-      pitch = (long)parent->line[1] - (long)parent->line[0];
+      pitch = (long long)parent->line[1] - (long long)parent->line[0];
       data = parent->line[0] +
              (bmp->y_ofs - parent->y_ofs) * pitch +
              (bmp->x_ofs - parent->x_ofs) * BYTES_PER_PIXEL(bitmap_color_depth(bmp));
diff --git a/src/win/wgdi.c b/src/win/wgdi.c
index 5d173a6897..5e79967a44 100644
--- a/src/win/wgdi.c
+++ b/src/win/wgdi.c
@@ -524,7 +524,7 @@ static struct BITMAP *gfx_gdi_init(int w, int h, int v_w, int v_h, int color_dep
 
    /* create the screen surface */
    screen_surf = _AL_MALLOC_ATOMIC(w * h * BYTES_PER_PIXEL(color_depth));
-   gdi_screen = _make_bitmap(w, h, (unsigned long)screen_surf, &gfx_gdi, color_depth, w * BYTES_PER_PIXEL(color_depth));
+   gdi_screen = _make_bitmap(w, h, (unsigned long long)screen_surf, &gfx_gdi, color_depth, w * BYTES_PER_PIXEL(color_depth));
    if (!gdi_screen) {
       _TRACE(PREFIX_E "Could not make a bitmap out of the screen surface.\n");	   
       goto Error;
diff --git a/src/win/wmidi.c b/src/win/wmidi.c
index 89b253c6f2..22ea14a8e1 100644
--- a/src/win/wmidi.c
+++ b/src/win/wmidi.c
@@ -242,8 +242,8 @@ int midi_win32_in_init(int input, int voices)
    id = (midi_input_driver->id & 0xFF) - 'A';
 
    /* open midi input device */
-   hr = midiInOpen(&midi_in_device, id, (DWORD)midi_in_proc,
-		   (DWORD)NULL, CALLBACK_FUNCTION);
+   hr = midiInOpen(&midi_in_device, id, (unsigned long long)midi_in_proc,
+		   (unsigned long long)NULL, CALLBACK_FUNCTION);
    if (hr != MMSYSERR_NOERROR) {
       _TRACE(PREFIX_E "midiInOpen failed (%x)\n", hr);
       midi_win32_in_exit(input);
diff --git a/src/win/wsndwo.c b/src/win/wsndwo.c
index 439eb6c09c..436aceb696 100644
--- a/src/win/wsndwo.c
+++ b/src/win/wsndwo.c
@@ -212,7 +212,7 @@ static void digi_waveout_mixer_callback(void)
       if (++digiwobufpos > (digiwobufdivs-1))
          digiwobufpos = 0;
 
-      _mix_some_samples((unsigned long) (digiwobufdata+((digiwobufsize/digiwobufdivs)*digiwobufpos)), 0, TRUE);
+      _mix_some_samples((unsigned long long) (digiwobufdata+((digiwobufsize/digiwobufdivs)*digiwobufpos)), 0, TRUE);
    }
 }
 
@@ -309,7 +309,7 @@ static int digi_waveout_init(int input, int voices)
       goto Error;
    }
 
-   _mix_some_samples((unsigned long) digiwobufdata, 0, TRUE);
+   _mix_some_samples((unsigned long long) digiwobufdata, 0, TRUE);
 
    /* get volume */
    waveOutGetVolume(hWaveOut, &initial_volume);