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2002-07-30 Joel Sherrill <joel@OARcorp.com>

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* miscellaneous.t: Added some markups for fonts and clarified
	some places.
This commit is contained in:
Joel Sherrill
2002-07-31 00:13:25 +00:00
parent 24c6364869
commit 2d35d1124f
2 changed files with 26 additions and 16 deletions
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5
doc/porting/ChangeLog
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@@ -1,3 +1,8 @@
2002-07-30 Joel Sherrill <joel@OARcorp.com>
* miscellaneous.t: Added some markups for fonts and clarified
some places.
2002-03-27 Ralf Corsepius <corsepiu@faw.uni-ulm.de>
* Makefile.am: Remove AUTOMAKE_OPTIONS.

37
doc/porting/miscellaneous.t
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@@ -10,7 +10,7 @@
@section Fatal Error Default Handler
The _CPU_Fatal_halt routine is the default fatal error handler. This
The @code{_CPU_Fatal_halt} routine is the default fatal error handler. This
routine copies _error into a known place -- typically a stack location or
a register, optionally disables interrupts, and halts/stops the CPU. It
is prototyped as follows and is often implemented as a macro:
@@ -46,7 +46,8 @@ peripheral controllers.
@subsection Specifying Processor Endianness
The CPU_BIG_ENDIAN and CPU_LITTLE_ENDIAN are set to specify the endian
The @code{CPU_BIG_ENDIAN} and @code{CPU_LITTLE_ENDIAN} are
set to specify the endian
format used by this microprocessor. These macros should not be set to the
same value. The following example illustrates how these macros should be
set on a processor family that is big endian.
@@ -60,18 +61,22 @@ set on a processor family that is big endian.
In a networked environment, each program communicating must agree on the
format of data passed between the various systems in the networked
application. Routines such as ntohl() and htonl() are used to convert
application. Routines such as @code{ntohl()}
and @code{htonl()} are used to convert
between the common network format and the native format used on this
particular host system. Although RTEMS has a portable implementation of
these endian conversion routines, it is often possible to implement these
routines more efficiently in a processor specific fashion.
The CPU_HAS_OWN_HOST_TO_NETWORK_ROUTINES is set to TRUE when the port
The @code{CPU_HAS_OWN_HOST_TO_NETWORK_ROUTINES} is set to TRUE when the port
provides its own implementation of the network to host and host to network
family of routines. This set of routines include the following:
@itemize @bullet
@item XXX list of routines in bullets
@item @code{ntohl()}
@item @code{ntohs()}
@item @code{htonl()}
@item @code{htons()}
@end itemize
The following example illustrates how this macro should be set when the
@@ -84,7 +89,7 @@ by this port:
@section Extra Stack for MPCI Receive Thread
The CPU_MPCI_RECEIVE_SERVER_EXTRA_STACK macro is set to the amount of
The @code{CPU_MPCI_RECEIVE_SERVER_EXTRA_STACK} macro is set to the amount of
stack space above the minimum thread stack space required by the MPCI
Receive Server Thread. This macro is needed because in a multiprocessor
system the MPCI Receive Server Thread must be able to process all
@@ -96,12 +101,12 @@ directives.
@subsection Endian Swap Unsigned Integers
The port should provide routines to swap sixteen (CPU_swap_u16) and
thirty-bit (CPU_swap_u32) unsigned integers. These are primarily used in
The port should provide routines to swap sixteen (@code{CPU_swap_u16}) and
thirty-bit (@code{CPU_swap_u32}) unsigned integers. These are primarily used in
two areas of RTEMS - multiprocessing support and the network endian swap
routines. The CPU_swap_u32 routine must be implemented as a static
routines. The @code{CPU_swap_u32} routine must be implemented as a static
routine rather than a macro because its address is taken and used
indirectly. On the other hand, the CPU_swap_u16 routine may be
indirectly. On the other hand, the @code{CPU_swap_u16} routine may be
implemented as a macro.
Some CPUs have special instructions that swap a 32-bit quantity in a
@@ -112,7 +117,7 @@ try to access the same "chunk" with the wrong endian. Another good reason
is that on some CPUs, the endian bit endianness for ALL fetches -- both
code and data -- so the code will be fetched incorrectly.
The following is an implementation of the CPU_swap_u32 routine that will
The following is an implementation of the @code{CPU_swap_u32} routine that will
work on any CPU. It operates by breaking the unsigned thirty-two bit
integer into four byte-wide quantities and reassemblying them.
@@ -141,8 +146,8 @@ in the shared memory driver and in network applications using the ntohl()
family of routines.
Most microprocessor families have rotate instructions which can be used to
greatly improve the CPU_swap_u32 routine. The most common way to do this
is to:
greatly improve the @code{CPU_swap_u32} routine. The most common
way to do this is to:
@example
swap least significant two bytes with 16-bit rotate
@@ -158,9 +163,9 @@ try to access the same "chunk" with the wrong endian. Another good reason
is that on some CPUs, the endian bit endianness for ALL fetches -- both
code and data -- so the code will be fetched incorrectly.
Similarly, here is a portable implementation of the CPU_swap_u16 routine.
Just as with the CPU_swap_u32 routine, the porter should provide a better
implementation if possible.
Similarly, here is a portable implementation of the @code{CPU_swap_u16}
routine. Just as with the @code{CPU_swap_u32} routine, the porter
should provide a better implementation if possible.
@example
#define CPU_swap_u16( value ) \