outb_p apod. - paused I/O - co to je?

[Alexandr Malusek]

Ales Pour <root na hnipak.sh.cvut.cz> writes:

> mohl by mi nekdo osvetlit rozdil mezi (napr.) outb a outb_p? V man pagi je
> u *_p fci receno ze jsou pro 'paused I/O; co je to? Moc diky.

Je to popsano v
http://www.linux.cz/linuxdoc/HOWTO/mini/IO-Port-Programming.html
Cituji:

The inb_p(), outb_p(), inw_p(), and outw_p() macros work otherwise
identically to the ones above (inb(), outb(), outw()), but they do an
additional short (about one microsecond) delay after the port access;
you can make the delay about four microseconds with #define
REALLY_SLOW_IO before you #include <asm/io.h>. These macros normally
(unless you #define SLOW_IO_BY_JUMPING, which is probably less
accurate) use a port output to port 0x80 for their delay, so you need
to give access to port 0x80 with ioperm() first (outputs to port 0x80
should not affect any part of the system).

--
A. Malusek  (malusek na ujf.cas.cz)
UJF AV CR