On 17 July 2013 23:16, Siarhei Siamashka <siarhei.siamas...@gmail.com> wrote:
> On Wed, 17 Jul 2013 16:52:49 +0200
> Christophe Lyon <christophe.l...@linaro.org> wrote:
>
>> Hi,
>>
>> Linaro is NOT an alternative to the Yocto project; we are
>> collaborating with them. For instance, there are recipes to build a
>> Yocto distribution using Linaro packages (e.g. the toolchain).
>>
>> Regarding the support of armv5te, if you build your toolchain from the
>> sources we provide, the support is included.
>> It's also present in the binary toolchains we provide, but these ones
>> default to generating code for armv7-a processors: you'll have to
>> force -march=XXX or -mcpu=YYY on your command line.
>
> Are you sure about this? You can try to:
>
> $ echo "int main(int argc,char *argv[]) {return 0xBADF00D/argc;}" >test.c
> $ arm-linux-gnueabihf-gcc -march=armv5te -marm test.c
> $ arm-linux-gnueabihf-objdump -d a.out
> And then have a look at the nice __aeabi_idiv implementation which gets
> linked in:
>
> 00008408 <__aeabi_idiv>:
> 8408: 2900 cmp r1, #0
> 840a: f000 813e beq.w 868a <.divsi3_skip_div0_test+0x27c>
>
> 0000840e <.divsi3_skip_div0_test>:
> 840e: ea80 0c01 eor.w ip, r0, r1
> 8412: bf48 it mi
> 8414: 4249 negmi r1, r1
> 8416: 1e4a subs r2, r1, #1
> 8418: f000 811f beq.w 865a <.divsi3_skip_div0_test+0x24c>
> 841c: 0003 movs r3, r0
> 841e: bf48 it mi
> 8420: 4243 negmi r3, r0
> 8422: 428b cmp r3, r1
> 8424: f240 811e bls.w 8664 <.divsi3_skip_div0_test+0x256>
> 8428: 4211 tst r1, r2
> 842a: f000 8123 beq.w 8674 <.divsi3_skip_div0_test+0x266>
> 842e: fab3 f283 clz r2, r3
> 8432: fab1 f081 clz r0, r1
> 8436: eba0 0202 sub.w r2, r0, r2
> 843a: f1c2 021f rsb r2, r2, #31
>
> ...
>
> Or maybe you have some plans to eventually provide multiple libgcc
> variants with the same binary toolchain, so that it can select the
> right one based on -march/-mcpu options?
Please check your a.out with
arm-linux-gnueabihf-readelf -A a.out
Linaro arm-linux-gnueabihf binary toolchain does support multilib:
arm-linux-gnueabihf-gcc --print-multi-lib
.;
arm-linux-gnueabi;@marm@march=armv4t@mfloat-abi=soft
But the armv4t is only expected for u-boot, which does not link the c
libraries in toolchain tarball (which is armv7-a).
We have no plan for full multilib support.
Thanks!
-Zhenqiang
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