On Thu, 9 Jan 2025, Eric W. Biederman wrote: > > So, this would be the 100% correct for alpha then which would not loose > > any functionality even for 32-bit binaries? > > I don't think it is correct to think about 32-bit binaries on alpha. > > Alpha never had a 32bit instruction set. But at some point it looks > like binaries that could not handle more than 31 bits of address > space got ported and someone implemented a work-around. I guess this > is the --taso option that Arnd mentioned. This also saves some code space in non-PIE and plain static executables as it takes fewer machine instructions to load a 64-bit address that is known beforehand to be a sign-extended 32-bit value. This is similar to the MIPS n32 ABI, which also implies a 32-bit address space while still using 64-bit registers for everything, starting from stack slots (it's also ILP32 with the `long long' C data type only making proper use of the full width of the CPU registers, while Alpha's --taso ABI is I believe IP32 (?) with the plain `long' C data type still 64-bit, just as with the regular LP64 ABI). This saving turned out quite important for some MIPS applications; less so for the Alpha, where indeed it was mainly a portability matter at the time when going beyond 32 bits (and writing clean code in the first place) was a big thing for some people. Maciej
