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Re: what's pio.h?

> So I see that we install machine/pio.h which defines functions like
> these (amd64):
> inb, insb, inw, insw, inl, insl; outb, outsb, ...

For i386, they are still inline functions.
I guess we can still enable them by i386_iopl(2) for
ancient programs using direct I/O in 386BSD days.
(note options(4) says we also had /dev/io in 1.1 and prior.)

For amd64 (and powerpc), they seem used only for kernel
(like <machine/acpi_machdep.h>) and provided by amd64/cpufunc.S etc.
Maybe they are not expected to work for userland binaries.
(though x86_64 still has x86_64_iopl(2) in libarch)

Izumi Tsutsui

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