Commits on Dec 19, 2023

1. Support 64-bit limbs on no-asm platforms …

   Currently, platforms without assembler support always use 32-bit limbs,
   but the Rust bindings always assume 64-bit limbs.  This breaks on
   big-endian platforms like our IBM Z (s390x).
   
   This patch enables 64-bit limbs on 64-bit platforms even if there is
   no hand-written assembler, by using a 128-bit integer type in the
   C implementation (this is an extension that is widely supported on
   64-bit platforms with GCC or LLVM).
   
   Note that this means that the argument "n" to quot_rem_n is no
   longer guaranteed to always be a multiple of 2, so the corresponding
   assertion needs to be removed as well.
   
   This fixes the broken Rust bindings on IBM Z, and also improves
   performance by a factor or 3 or more, because compiler-generated
   code handling __int128 already uses the 64x64->128 multiply
   instruction our ISA provides.
   
   To improve performance of compiler-generated code a bit more, this
   also switches to the -O3 optimization level, which helps with
   unrolling of the Montgomery multiply core loop.

   

   uweigand committed Dec 19, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for c2407b5
   • Browse repository at this point

   Copy the full SHA

   c2407b5 View commit details

   Browse the repository at this point in the history