INB(9) INB(9)
NAME
inb, ins, inl, outb, outs, outl, insb, inss, insl, outsb,
outss, outsl - programmed I/O
SYNOPSIS
int inb(int port)
ushort ins(int port)
ulong inl(int port)
void outb(int port, int value)
void outs(int port, ushort value)
void outl(int port, ulong value)
void insb(int port, void *address, int count)
void inss(int port, void *address, int count)
void insl(int port, void *address, int count)
void outsb(int port, void *address, int count)
void outss(int port, void *address, int count)
void outsl(int port, void *address, int count)
DESCRIPTION
The x86 implementation provides functions to allow kernel
code written in C to access the I/O address space. On sev-
eral other architectures such as the PowerPC and Strongarm,
the platform-dependent code provides similar functions to
access devices with an I/O space interface, even when that
is memory mapped, to encourage portability of device
drivers.
Inb, ins and inl apply the corresponding hardware instruc-
tion to fetch the next byte, short or long from the I/O
port. Outb, outs and outl output a value to the I/O port.
The remaining functions transfer count bytes, shorts, or
longs using programmed I/O between a memory address and
port. Functions insX copy values into memory; functions
outsX copy values from memory. The count is in elements,
not bytes.
SOURCE
/sys/src/9/pc/l.s
Page 1 Plan 9 (printed 12/21/24)
INB(9) INB(9)
SEE ALSO
dma(9)
Page 2 Plan 9 (printed 12/21/24)