source: rtems/c/README.DOS @ 9e738b65

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tools
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The RTEMS build procedure was designed with the capabilitiies of a 
typical UNIX computer in mind.  Making this procedure work under MS-DOS
is not that difficult but requires that MS-DOS versions of a number
of UNIX utilities be acquired and installed.  For time being, the 
best advice which can be offered is:

    "This is a nasty question, since when I first set up the DOS machine
     (long before I acquired RTEMS) I ftp'd a bunch of different tool
     sets (all from SimTel), and then picked individual tools from each 
     set that worked best for me.  The djgpp tools are probably a good 
     starting point, especially to get a working sed.  Next the gnu tools 
     in SimTel/msdos/gnuish, and then others.  Sorry I can't give you more
     specific names.  The only real requirement for the tools is that
     they *must* accept redirection of command line arguments from a file
     using the '@' notation (i.e., "mkdir @/tmp/args" reads the argument
     list from file /tmp/args)."

There is a special version (source and executable) of GNU make 3.71 for
MS-DOS which minimizes the amount of memory used by recursive makes
available on lancelot.gcs.redstone.army.mil in the directory: ... XXX

go32
----
go32 dumps the stack when a program seg-faults, and if this happens while
on an alternate stack an infinite loop can ensue.  Setting the environment
variable GO32="core /tmp/core" will prevent more than 20 lines or
so of stack information from being dumped after a crash, and the output
will go to a file rather than the screen.

The go32 debuggers get confused by the relocated stacks used by tasks,
and tend to crash when variables are inspected.

make directory
--------------
gcc-go32.cfg is used for cross compiling to the go32 environment under RTEMS,
while djgcc.cfg is used for "native" compilation; i.e. under MSDOS rather
than under RTEMS.  The difference is that "native" compilation uses the djgpp
I/O libraries, while "cross" compilation uses the RTEMS I/O libraries.

djgcc.cfg is identical to gcc.cfg, except for the omission of the -pipe
option.

djgcc include files
-------------------
In general, we use RTEMS include files because these contain the proper
declarations for the libc, and in particular, the stdio functions.
When calling go32-specific functions it is necessary to include some 
djgpp include files, as well.  Unfortunately, there are some disagreements
between RTEMS and djgpp as to how certain functions and types are 
declared.  In these cases, I have modified to RTEMS source to special-
case the differences.

cpu-specific files
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rtems/c/src/exec/cpu/i80386 is intended to contain 386-specific
functions for RTEMS.  Since under djgpp we do not have *complete*
control of the processor, we must cooperate with the djgpp runtime
environment, this directory cannot be shared between the go32 port
and other 386 BSPs.

other
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* F12 will immediately abort the program.
See libbsp/i80386/go32/iosupp/inch.c.

* libbsp/i80386/go32/timer uses the on-board timer chip by default.
However, if executing on a Pentium processor you can use the on-chip
64-bit cycle counter, which counts at whatever clock rate your processor
runs at.  To use this, compile with -DPENTIUM