(gdb) where
...
#4  0x000055e8fe1d1d14 in HandleCrash (signum=11) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/os/unix/crashlog_unix.cpp:175
#5  <signal handler called>
#6  0x000055e8fe13b7a3 in Blitter_32bppAnim::Draw<(BlitterMode)0> (zoom=<optimized out>, bp=0x7ffc4cda0790, this=0x55e901c43410) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/blitter/32bpp_anim.cpp:234
#7  Blitter_32bppAnim::Draw (this=0x55e901c43410, bp=0x7ffc4cda0790, mode=<optimized out>, zoom=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/blitter/32bpp_anim.cpp:264
#8  0x000055e8fe490f24 in GfxBlitter<4, false>(Sprite const*, int, int, BlitterMode, SubSprite const*, unsigned int, ZoomLevel, DrawPixelInfo const*) [clone .constprop.0] (sprite=<optimized out>, x=<optimized out>,
    y=<optimized out>, mode=BM_NORMAL, sub=<optimized out>, sprite_id=<optimized out>, zoom=ZOOM_LVL_OUT_2X, dst=0x0) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/gfx.cpp:1186
#9  0x000055e8fe2d5473 in GfxMainBlitterViewport (sprite_id=1012, sub=0x0, mode=BM_NORMAL, y=12800, x=-20992, sprite=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/gfx.cpp:1232
#10 DrawSpriteViewport (img=<optimized out>, pal=0, x=-20992, y=12800, sub=0x0) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/gfx.cpp:1028
#11 0x000055e8fe4704b1 in ViewportDrawTileSprites (tstdv=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:1496
#12 ViewportDoDraw (vp=0x7f09dc33b9b0, left=<optimized out>, top=<optimized out>, right=<optimized out>, bottom=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:1747
#13 0x000055e8fe470e97 in ViewportDraw (bottom=<optimized out>, right=<optimized out>, top=<optimized out>, left=<optimized out>, vp=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:1803
#14 Window::DrawViewport (this=0x7f09dc301110) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:1823
#15 0x000055e8fe481995 in NWidgetViewport::Draw (this=0x7f09dc3011e0, w=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/widget.cpp:2051
#16 0x000055e8fe47c704 in NWidgetPIPContainer::Draw (this=<optimized out>, w=0x7f09dc301110) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/widget.cpp:1236
#17 0x000055e8fe47a5f1 in Window::DrawWidgets (this=0x7f09dc301110) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/widget.cpp:638
#18 0x000055e8fe3206e0 in MainWindow::OnPaint (this=0x7f09dc301110) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/main_gui.cpp:247
#19 0x000055e8fe47f80e in DrawOverlappedWindowForAll (left=0, top=<optimized out>, right=791, bottom=1056) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/window.cpp:983
#20 0x000055e8fe2d619f in RedrawScreenRect (left=0, top=0, right=791, bottom=1056) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/gfx.cpp:1587
#21 0x000055e8fe46e728 in DoSetViewportPosition (it=..., left=<optimized out>, top=<optimized out>, width=<optimized out>, height=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:279
#22 0x000055e8fe46e874 in SetViewportPosition (w=<optimized out>, x=<optimized out>, y=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:387
#23 0x000055e8fe46eaf9 in UpdateViewportPosition (w=0x7f09dc301110) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/viewport.cpp:1898
#24 0x000055e8fe30ce49 in SelectGameWindow::OnRealtimeTick (this=0x7f09dc301320, delta_ms=<optimized out>) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/intro_gui.cpp:234
#25 0x000055e8fe485249 in CallWindowRealtimeTickEvent (delta_ms=delta_ms@entry=16) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/window.cpp:3051
#26 0x000055e8fe48802a in UpdateWindows () at /usr/src/debug/openttd-12.0-1.1.x86_64/src/window.cpp:3070
#27 0x000055e8fe252690 in VideoDriver::Tick (this=0x55e9016f63f0) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/video/video_driver.cpp:149
#28 0x000055e8fe252818 in VideoDriver_SDL::MainLoop (this=0x55e9016f63f0) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/video/sdl_v.cpp:652
#29 0x000055e8fe3855f1 in openttd_main (argc=<optimized out>, argv=0x7ffc4cda0e80) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/openttd.cpp:802
#30 0x00007f0a18d12540 in __libc_start_call_main (main=main@entry=0x55e8fdfe4be0 <main(int, char**)>, argc=argc@entry=1, argv=argv@entry=0x7ffc4cda3198) at ../sysdeps/nptl/libc_start_call_main.h:58
#31 0x00007f0a18d125ec in __libc_start_main_impl (main=0x55e8fdfe4be0 <main(int, char**)>, argc=1, argv=0x7ffc4cda3198, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7ffc4cda3188) at ../csu/libc-start.c:409
#32 0x000055e8fe080105 in _start () at ../sysdeps/x86_64/start.S:116
(gdb) frame 6
#6  0x000055e8fe13b7a3 in Blitter_32bppAnim::Draw<(BlitterMode)0> (zoom=<optimized out>, bp=0x7ffc4cda0790, this=0x55e901c43410) at /usr/src/debug/openttd-12.0-1.1.x86_64/src/blitter/32bpp_anim.cpp:234
234                                                                     *dst = ComposeColourPANoCheck(this->AdjustBrightness(this->LookupColourInPalette(m), GB(*src_n, 8, 8)), src_px->a, *dst);
(gdb) l
229                                             } else {
230                                                     do {
231                                                             uint m = GB(*src_n, 0, 8);
232                                                             *anim++ = 0;
233                                                             if (m >= PALETTE_ANIM_START) {
234                                                                     *dst = ComposeColourPANoCheck(this->AdjustBrightness(this->LookupColourInPalette(m), GB(*src_n, 8, 8)), src_px->a, *dst);
235                                                             } else {
236                                                                     *dst = ComposeColourRGBANoCheck(src_px->r, src_px->g, src_px->b, src_px->a, *dst);
237                                                             }
238                                                             dst++;
(gdb) disass 0x000055e8fe13b7a3
Dump of assembler code for function _ZN17Blitter_32bppAnim4DrawEPN7Blitter13BlitterParamsE11BlitterMode9ZoomLevel:
...
   0x000055e8fe13b789 <+2345>:  shr    $0x8,%esi
   0x000055e8fe13b78c <+2348>:  add    %esi,%edx
   0x000055e8fe13b78e <+2350>:  movzbl 0x2(%r12),%esi
   0x000055e8fe13b794 <+2356>:  sub    %r8d,%esi
   0x000055e8fe13b797 <+2359>:  imul   %edi,%esi
   0x000055e8fe13b79a <+2362>:  shr    $0x8,%esi
   0x000055e8fe13b79d <+2365>:  add    %esi,%ecx
   0x000055e8fe13b79f <+2367>:  add    $0x2,%rbp
=> 0x000055e8fe13b7a3 <+2371>:  mov    %al,(%rbx)
   0x000055e8fe13b7a5 <+2373>:  add    $0x4,%r12
   0x000055e8fe13b7a9 <+2377>:  add    $0x4,%rbx
   0x000055e8fe13b7ad <+2381>:  mov    %dl,-0x3(%rbx)
(gdb) p/x $rbx
$2 = 0x7f0a16347000
(gdb) p dst
$3 = (Colour *) 0x7f0a16347000