libx32

/lib/ is for 32-bit apps
/libx32/ is for the 32x ABI

In the new "x32" ABI x86_64-linux-gnux32,
inspired by SGI n32 environment,
registers are 64 bits,
but pointers, integers and longs are only 32 bits,
saving a lot of memory in pointer-heavy workflows.
It also ensures all the other 64-bit only processor features are available,
resulting in to about 30% reduction in memory usage
and up to about 40% increase in speed. [2][5]

It is designed to run on 64bit host
(amd64/x86_64 CPUs)
which gives it full access to all x64 goodies:
 o native x64 registers and math
 o more registers
 o SSE2/3/4, AVX1/2/...
 o Full 4Gb address space on 64bit host [3]

It is part of Linux 3.4,
released on the 20th May 2012 [4]

The idea is to combine the smaller memory and cache footprint from 32-bit data types
with the larger register set of x86_64. [5]

Requirements:
 - kernel support (3.4 and above),
 - distro support (see below),
 - libc support (2.11 or above),
 - GCC 4.8 and above (improved address size prefix support).

When booting a kernel with the support,
you must use syscall.x32=y option [5]


 [1] https://stackoverflow.com/a/851229/212044
 [2] https://stackoverflow.com/a/36347228/212044
 [3] https://stackoverflow.com/a/36347144/212044
 [4] https://stackoverflow.com/q/7635013/212044
 [5] https://stackoverflow.com/a/32663236/212044
 [6] https://unix.stackexchange.com/a/539354/22046
 [7] https://www.quora.com/Systems-Programming/What-is-the-exact-difference-between-dynamic-loading-and-dynamic-linking/answer/Jeff-Darcy
 [8] https://unix.stackexchange.com/a/476783/22046
 [9] https://stackoverflow.com/a/76490135/212044
[10] https://stackoverflow.com/a/75630806/212044