I'm being pedantic, but on modern hardware, the ISA is an abstraction over microarchitecture and microcode. It's no longer a 1-to-1 representation of hardware execution. But, as programmers, it's as low as we can go, so the distinction is academic.
I'm being pedantic, but on modern hardware, the ISA is an abstraction over microarchitecture and microcode. It's no longer a 1-to-1 representation of hardware execution. But, as programmers, it's as low as we can go, so the distinction is academic.
Still one layer below C, and with plenty of features not available on C source code.
Compiler intrinsics do give you C/C++ api access to relevant ISA subsets as platform-specific extensions.