> Am 31.03.2024 um 21:35 schrieb Florian Klämpfl via fpc-devel
> <fpc-devel@lists.freepascal.org>:
>
>
>
>> Am 31.03.2024 um 17:11 schrieb Michael Ring via fpc-devel
>> <fpc-devel@lists.freepascal.org>:
>>
>> 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,
>
> Can you post some more context? fpc_initalize is not that big so it should be
> possible to identify where this comes from.
Ok, I think I found it, it is one for Gareth:
var
i : longint;
begin
case i of
1: writeln(1);
2: writeln(2);
3: writeln(2);
4: writeln(2);
5: writeln(2);
end;
end.
ppcarm -Cparmv6m -al -O2 t.pp -Tlinux -Oonopeephole
results in:
...
sub r1,#1
lsl r1,r1,#2
ldr r0,.Lj11
ldr r0,[r0, r1]
mov r15,r0
.balign 4
.La1:
.long .Lj4
.long .Lj5
.long .Lj6
.long .Lj7
.long .Lj8
…
The peephole removes the alignment before case jump tables: if no -Oonopeephole
is passed, the .balign 4 is gone.
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