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by SAI_Peregrinus 1815 days ago
Correct. There are a few cases where the operands don't fit into a single machine word, the most notable being many cryptographic operations. Particularly RSA and ECC, which involve multiple-precision arithmetic.

There are also non-Linux cases, mostly microcontrollers. EG the Arm Cortex M0 doesn't have a hardware multiplier, the M0+ does.

And then there's that one guy who got Linux running on an 8-bit AVR by emulating a 32-bit ARM and running it on that[1]. I'd consider this a silly edge case. Too fun not to mention though.

[1] https://dmitry.gr/?r=05.Projects&proj=07.%20Linux%20on%208bi...