[LLVMdev] error: instruction requires: thumb2

[Lei Zhao]

Aha, thanks.

- Lei

On Aug 16, 2012, at 6:02 PM, Jim Grosbach wrote:

> Sure. Use legal ARM mode syntax for the instruction.
> 
> Specifically, there is no offset immediate for the ARM mode LDREX instruction. It's illegal syntax to supply one, even if it's zero.
> 
> -Jim
> 
> On Aug 16, 2012, at 2:36 PM, Lei Zhao <leizhao833 at gmail.com> wrote:
> 
>> It works. But a follow-up question: why do I have to compile it to thumb mode in order to pass the compilation? Is there a way to make it compile to regular arm mode? Thanks.
>> 
>> - Lei
>> 
>> On Aug 16, 2012, at 4:00 PM, Eli Friedman wrote:
>> 
>>> On Thu, Aug 16, 2012 at 12:55 PM, Lei Zhao <leizhao833 at gmail.com> wrote:
>>>> Hi Everybody,
>>>> 
>>>> I recently did a cross-compiling using clang (built with host=x86, target=arm) with the following command:
>>>> 
>>>>> clang -march=armv7-a -mfloat-abi=soft -ccc-host-triple arm-none-linux-gnueabi -integrated-as main.c -o main.o -c
>>>> 
>>>> and get error message:
>>>> 
>>>> -------------------------------------------------------
>>>> main.c:9:9: error: instruction requires: thumb2
>>>>      "ldrex %[oldValue], [%[ptr], #0]\n" // oldValue = *ptr
>>>>      ^
>>>> <inline asm>:1:2: note: instantiated into assembly here
>>>>      ldrex r6, [r4, #0]
>>>>      ^
>>>> main.c:11:3: error: instruction requires: thumb2
>>>>      "strexeq %[failed], %[newValue], [%[ptr], #0]\n"
>>>>       ^
>>>> <inline asm>:3:1: note: instantiated into assembly here
>>>> strexeq r5, lr, [r4, #0]
>>>> ^
>>>> 2 errors generated.
>>>> -------------------------------------------------------
>>>> 
>>>> In the main.c, some ARM assembly are embedded which contains instructions ldrex, strexeq. I don't know what the message suggests since the cpu specified does support thumb2. Could someone help? Thanks.
>>> 
>>> Try "-mthumb".
>>> 
>>> -Eli
>> 
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>