Cannot compile/assemble some assembly modules as PIC

[wernerd]

In my fork of SIDH to add Cmake, C++ wrapper, Android, Java support I build a shared library which includes the SIDH modules. To support Android applications a shared library is a pre-requisite.

When compiling/assemble fp_x64_asm.S clang reports a problem that it cannot generate position independent code (-fpic).

The offending lines in file fp_x64_asm.S look like this

    MUL128x256_SCHOOL [reg_p1], [rip+p434p1+24], r8, r9, r10, r11, r12, r13, rcx     

The culprit here is the reference to p434p1 which is a global variable in the C-sources. The same holds for p503p1, p610p1, and p751p1 variables in their respective assembler files. Tested using clang V9.0.1.

Because I'm not familiar with x86 assembler ;-) I could not fix this and thus reverted to the generic modules to build the shared library. These are definitely slower than the optimized assembler code.

I found some other smaller issues when building the shared library, however these could be easily solved - I show them in another issue.

[christianpaquin]

The Open Quantum Safe library incorporates the different SIDH parameters under a common library, either static or shared. The project also supports multiple platforms and provides non-C language wrappers; someone is working on an android build. It also now builds with cmake. You might want to call SIDH from this abstraction layer instead, to facilitate your integration.

[wernerd]

Thanks for the feedback. Actually the Android support is already working within my fork :-) and I have a small test app already. Next step for me is to include the SIDH modules into my ZRTPCPP library. The fork and the cmake support etc actually is a pre-requisite to include the modules into ZRTPCPP (which I did already back in 2017 with the first version of SIDH :-) ). I did a quick check, the lines which gave me problems are also in the .S files in the project. This could lead to some problems IMHO. Werner Am 20.02.20 um 20:06 schrieb Christian Paquin:

…

The Open Quantum Safe library <https://github.com/open-quantum-safe/liboqs> incorporates the different SIDH parameters under a common library, either static or shared. The project also supports multiple platforms and provides non-C language wrappers; someone is working on an android build <open-quantum-safe/liboqs#594>. It also now builds with cmake. You might want to call SIDH from this abstraction layer instead, to facilitate your integration. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#25?email_source=notifications&email_token=AAD6DEN62MCIZ47NZ7YKF23RD3IBRA5CNFSM4KYUOQMKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEMPVL4Q#issuecomment-589256178>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAD6DEJ7SM6XK6GVT7W4IQTRD3IBRANCNFSM4KYUOQMA>.

-- Werner Dittmann email: Werner.Dittmann@t-online.de cell: +49 173 44 37 659 PGP key: 82EF5E8B