[fpc-devel] Unaligned access on Cortex-M0 in Initialization code

[Michael Ring]

Hi,

it has been a while since I have been deep,deep down in the rabbit hole 
of Cortex Assembly, so please forgive me if I am overlooking something...

I have an application for Raspberry Pico (target embedded) and it fails 
during initialization as soon as I add a unit that includes an object 
and I reference the object in my code...

In that case fpc_initialize (for rtti?) is called and I cannot find 
source code for fpc_initialize

In the debugger I see that R0 is $1000177E and R1 is $28 This is in the 
flash area, so far, so good but $1000177E is obviously not word 
alligned, it is halfword aligned so this then triggers _HardFault_Handler.

10001778 4648                     ldr             r0, [pc, #280] ; 
(0x10001894 <fpc_initialize+316>)
1000177A 4058                     ldr             r0, [r0, r1] ; Crash 
Boom Bang !!!!!

Looking at the map file the address is within fpc_initialize, but as I 
cannot find the proper source I am a bit lost...

.text.n_fpc_initialize
                 0x0000000010001758      0x144 
/Users/tgdrimi9/fpcupdeluxe/fpc/units/arm-embedded/armv6m/eabi/rtl/system.o
                 0x0000000010001758                fpc_initialize
                 0x0000000010001758                FPC_INITIALIZE
  .text.n_fpc_finalize
                 0x000000001000189c      0x164 
/Users/tgdrimi9/fpcupdeluxe/fpc/units/arm-embedded/armv6m/eabi/rtl/system.o

Any help appreciated,


Michael