create x86_64 BSP

[Joel Sherrill]

On 8/7/2015 8:38 AM, Gedare Bloom wrote:
> An x86_64 BSP would be a welcome addition for testing purposes, which
> Amar is interested in, and for getting another 64-bit target ported.
> The best place to start would be to read the CPU supplement and BSP
> porting guide. Any new architecture will need a GCC toolchain, which
> is relatively straightforward but takes some time to add the correct
> config lines into GCC. I've CC'd Hesham, as he has the most recent
> experience with porting RTEMS to new architectures, so he might know
> where you can find more information.

That's about the task list. You definitely have to get the tools
for x86_64-rtems building. You will have to file FSF paperwork if
you do the port. I am pretty quick at these so can take a swing
at giving you a patch. Then you (like Hesham did) can figure out
if I missed anything or didn't tweak it correctly.

The next step is to get a stub port (score/cpu) and stub bsp
(libbsp/x86_64) building with the toolset. That gives you
a buildable framework to place code in.

Beyond that, I recommend starting at the linker script and
start code and just working straight through what is needed
for hello world. Then add the clock driver and run ticker.
Followed by a benchmark timer driver.

An early investigation step is running base code compiled
with x86_64-elf on qemu. If that works, you have great
executable references for linker script, start code, and
basic console IO.

setjmp/longjmp in newlib are a handy starting point for
context switch code.

Growth from there will likely be leveraging modern peripherals
from pc386.

> Gedare
>
> On Fri, Aug 7, 2015 at 2:19 AM, punit vara <punitvara at gmail.com> wrote:
>> I have thought of creating BSP for x86_64 but unfortunately I was busy
>> in my exam and class hectic schedule.Shall I create or work on  BSP
>> for X86_64  ?
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>

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Joel Sherrill, Ph.D.             Director of Research & Development
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