.\" $OpenBSD: inb.2,v 1.3 2003/03/06 04:07:37 david Exp $
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.\" Copyright (c) 2002 Matthieu Herrb
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.Dd July 6, 2002
.Dt LIBALPHA 2
.Os
.Sh NAME
.Nm dense_base ,
.Nm inb ,
.Nm inl ,
.Nm inw ,
.Nm ioperm ,
.Nm map_memory ,
.Nm outb ,
.Nm outl ,
.Nm outw ,
.Nm readb ,
.Nm readl ,
.Nm readw , 
.Nm unmap_memory ,
.Nm writeb , 
.Nm writel ,
.Nm writew
.Nd Alpha devices I/O ports and memory access functions
.Sh SYNOPSIS
.Ft u_int64_t
.Fn dense_base "void"
.Ft u_int8_t
.Fn inb "u_int32_t port"
.Ft u_int32_t
.Fn inl "u_int32_t port"
.Ft u_int16_t
.Fn inw "u_int32_t port"
.Ft int
.Fn ioperm "unsigned long from" "unsigned long num" "int on"
.Ft void *
.Fn map_memory "u_int32_t address" "u_int32_t size"
.Ft void
.Fn outb "u_int32_t port" "u_int8_t val"
.Ft void
.Fn outl "u_int32_t port" "u_int32_t val"
.Ft void
.Fn outw "u_int32_t port" "u_int16_t val"
.Ft u_int8_t
.Fn readb "void *handle" "u_int32_t offset"
.Ft u_int32_t
.Fn readl "void *handle" "u_int32_t offset"
.Ft u_int16_t
.Fn readw "void *handle" "u_int32_t offset"
.Ft void
.Fn unmap_memory "void *handle" "u_int32_t size"
.Ft void
.Fn writeb "void *handle" "u_int32_t offset" "u_int8_t val"
.Ft void
.Fn writel "void *handle" "u_int32_t offset" "u_int32_t val"
.Ft void
.Fn writew "void *handle" "u_int32_t offset" "u_int16_t val"
.Sh DESCRIPTION
The functions in libalpha give userland programs access to the I/O
ports on the OpenBSD/alpha platform. 
.Pp
The 
.Fn in*
functions return data read from the specified I/O port. 
.Pp
The 
.Fn out*
functions write data to the specified I/O port. 
.Pp
.Fn ioperm
enables access to the specified port numbers if 
.Fa on
is 
.Dv TRUE
and disables access if 
.Fa on
is 
.Dv FALSE . 
.Pp 
The 
.Fn map_memory 
function allows a user program to map part of a device memory.
.Pp
The 
.Fn unmap_memory
function unmaps memory that was previously mapped by
.Fn map_memory . 
.Pp
The
.Fn read*
functions read data from device memory previously mapped by
.Fn map_memory . 
.Pp
The 
.Fn write*
functions write data to the device memory previously mapped by
.Fn map_memory .
.\" .Sh EXAMPLES
.\" TBW
.Sh HISTORY
These functions originally appeared in
.Fx .
.Sh CAVEATS
Only BWX bus access method is supported for now. Machines requiring
swiz type access are not supported. 
.Pp
Root credentials are needed to use these functions.