Re:Reverse-engineering the division microcode in the Intel 8...
by andoma on Saturday April 08, 2023 @03:51PM
(#35496941)
Pretty sure some of the low-end Cortex-M cores (M0 and M1) lacks instructions for division.
Re:Reverse-engineering the division microcode in the Intel 8...
by pm215 on Saturday April 08, 2023 @03:59PM
(#35497009)
Good point, it's not in v6M, though it is in v8M baseline, which is the v8 equivalent. So M0, M0+ and M1 don't have it but I think everything else M-profile should.
Re:Reverse-engineering the division microcode in the Intel 8...
by colejohnson66 on Monday April 10, 2023 @07:40AM
(#35511210)
Given that Ken said most ARM processors, the nerd sniping becomes: what percentage of all ARM cores are M0/M0+/M1. I'd guess a lot (maybe not half though). Don't all micro SD cards have a processor inside them? They're probably almost all ARM...
The footnote that says "most ARM processors still don't have integer division" seems a little out of date to me -- all 64-bit Arm cores do, of course, and on the 32-bit side anything since v7VE (Cortex-A15 was the first of these, released 2011) does, and all the M-profile microcontroller cores have it. It's a bit unfortunate it didn't make it into v7, since that's a pretty popular 32-bit compilation target, but the runtime libs should use it even if the compiler can't opencode a division insn.