http://benji3up2kxewkqfcq7buxk2xd6zwy3zggnurkrm3l4cvwy2iipvyyad.onion/mirrors/gmpdoc/ABI-and-ISA.html
GMP performance is the same in both. ‘ ABI=32 ’ In the 32-bit ABI, pointers, int s and long s are 32 bits and GMP
uses a 64 bit long long for a limb. Applications can be compiled
without any special flags since this ABI is the default in both HP C and GCC,
but for reference the flags are gcc -milp32
cc +DD32 ‘ ABI=64 ’ In the 64-bit ABI, long s and pointers are 64 bits and GMP uses a long for a limb.