The Linux x32 ABI for x86_64 processors allow making use of the full 64-bit register file and wide data path but retaining 32-bit pointers to provide for a smaller memory footprint when not needing 64-bit pointers. Linux x32 came to the party late and didn't enjoy much adoption over the years and is now looking at possible removal from the Linux kernel...
Source: Phoronix — read the full report at the original publisher.