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Re: [PATCH][binutils][Arm][2/3] Add support for float16 (IEEE and Alternative formats) for Arm backend.
- From: Barnaby Wilks <Barnaby dot Wilks at arm dot com>
- To: "nickc at redhat dot com" <nickc at redhat dot com>, "binutils at sourceware dot org" <binutils at sourceware dot org>
- Cc: nd <nd at arm dot com>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, "Ramana Radhakrishnan" <Ramana dot Radhakrishnan at arm dot com>
- Date: Fri, 9 Aug 2019 13:11:20 +0000
- Subject: Re: [PATCH][binutils][Arm][2/3] Add support for float16 (IEEE and Alternative formats) for Arm backend.
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Hi Nick,
On 8/9/19 1:31 PM, Nick Clifton wrote:
> Hi Barnaby,
>
>> Cross compiled and regtested on arm-none-eabi and arm-none-linux-gnueabihf
> Are you sure ? I am seeing the following new assembler failures when I test the patch:
>
> FAIL: Invalid float16 literals (IEEE 754 & Alternative)
> FAIL: Big endian float16 literals (IEEE 754 & Alternative)
> FAIL: Tag_ABI_FP_16bit_format EABI attribute written for Arm alternative format.
> FAIL: Tag_ABI_FP_16bit_format written for IEEE float16 format.
> FAIL: Tag_ABI_FP_16bit_format EABI attribute not written when format not specified
> FAIL: Invalid combination of command line arguments and directives
> FAIL: Little endian float16 literals (IEEE 754 & Alternative)
>
> (This is with lots of different configurations of ARM based toolchains).
>
> The problem seems to be the same with all of the tests. Eg:
>
> gas/testsuite/gas/arm/float16.s: Assembler messages:
> gas/testsuite/gas/arm/float16.s:2: Error: cannot create floating-point number
> gas/testsuite/gas/arm/float16.s:2: Error: junk at end of line, first unrecognized character is `1'
>
> It looks like the patch is maybe missing a change to atof_ieee.c to handle the 'h'
> format maybe ?
Ah yeah, both the Arm and AArch64 patches require the changes to atof_ieee.c in
[PATCH][binutils][1/3] Generic support for IEEE 754 floating point numbers.
( https://sourceware.org/ml/binutils/2019-07/msg00115.html )
The generic patch add support for the 'h' format, which is (as you say) needed for this patch to work,
otherwise it will rather unhelpfully error.
Apologies for forgetting to mention this, it would have been a useful thing to point out :)
>
> Cheers
> Nick
Regards,
Barney