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arch(3): document #P/realmodemem file

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cinap_lenrek 2017-12-23 04:45:22 +01:00
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commit 9c6897e848
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7
sys/man/3/arch
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@ -15,6 +15,7 @@ arch \- architecture-specific information and control
.B /dev/iow
.B /dev/irqalloc
.B /dev/msr
.B /dev/realmodemem
.SH DESCRIPTION
This device presents textual information about PC hardware and allows
user-level control of the I/O ports on x86-class machines.
@ -129,6 +130,12 @@ Reads and writes to
.I msr
go to the P4/P6/Core/Core2/AMD64 MSRs.
.PP
The
.I realmodemem
file provides access to the first megabyte of memory. This
allows reading BIOS data structures and option ROMs.
Writing is limited to the VGA framebuffer at [0xA0000-0xBFFFF].
.PP
Reads and writes to
.I ec
transfer bytes from and to the embedded controller.