Re: some question about aarch32 for ARM64

[loody]

hi catalin:

2015-02-23 21:27 GMT+08:00 Catalin Marinas <catalin.marinas@xxxxxxx>:
> On Mon, Feb 23, 2015 at 12:28:57PM +0000, loody wrote:
>> I follow below instructions to compile a simple c file as aarch32 but in vain.
>>
>> https://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/AArch64-Options.html#AArch64-Options
>
> On the above link, there are no instructions on how to compile an
> AArch32 application with the AArch64 compiler. You need an AArch32 gcc
> (e.g. arm-linux-gnu-gcc, not aarch64-linux-gnu-gcc).
>
>> I saw there are aarch32 support in arm64 kernel porting.
>
> Yes, that's to support AArch32 binaries (ARMv8/v7/...).
>
>> Would you mind to let us know how to get aarch32 ELF for running on
>> ARM64 processors?
>
> Just use the right compiler.
>
>> PS:Below is my compile error message:
>> #aarch64-linux-gnu-gcc -mabi=ilp32 test.c
>
> -mabi=ilp32 is entirely different from an AArch32 compiler. The above
> still generates AArch64 but with the ILP32 ABI (sizeof int/long/pointer
> is 32-bit).
so per your explanation, AArch32 binary could be created by any
arm-linux-gnu-gcc which support armv7 and previous instructions.
And -mabi=ilp32 is still aarch64 but with ILP32 ABI.
appreciate your kind help ^^
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