<br><br><div class="gmail_quote">2009/7/29 Mike Panetta <span dir="ltr"><<a href="mailto:mprtems@bellsouth.net">mprtems@bellsouth.net</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im"><br>
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----- Original Message ----<br>
> From: Joel Sherrill <<a href="mailto:joel.sherrill@oarcorp.com">joel.sherrill@oarcorp.com</a>><br>
> To: Mike Panetta <<a href="mailto:mprtems@bellsouth.net">mprtems@bellsouth.net</a>>; "<a href="mailto:rtems-users@rtems.org">rtems-users@rtems.org</a>" <<a href="mailto:rtems-users@rtems.org">rtems-users@rtems.org</a>><br>
> Sent: Friday, July 24, 2009 10:41:21 AM<br>
> Subject: Re: Cortex-M3 support?<br>
><br>
> Sebastian Huber has been reworking the ARM exception code so<br>
> make sure you are on today's head and talking to him.<br>
<br>
</div>I don't have his email address, should it be in the list archives?<br>
He has not posted recently in reply to this message, so I am<br>
not quite sure how to contact him.<br>
<div class="im"></div></blockquote><div><br>Add Sebastian Huber in the loop. He might be busy with LPC porting now.<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im"><br>
><br>
> In general terms, you want to start with the CPU core and<br>
> ignore the peripherals.<br>
><br>
> + make sure the multilib variant is in the tools<br>
> + make sure the multilib variant is properly supported<br>
> by cpukit/score/arm and the libnetworking cksum routines.<br>
<br>
</div>Its in the tools, but the score code seems to be dependent on<br>
non thumb ASM so it will not compile for the Cortex-M3.<br>
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Specifically the context switching code is explicitly in ARM mode.<br>
<div class="im"></div></blockquote><div><br>You can refer to make/custom/rtl22xx_t.cfg and rtl22xx_t BSP. This is a Thumb BSP. Try the "-mcpu=cortex-m3 -mthumb" flag for cortext-m3. I think no one have ever tried the cortex-m3 flag with rtems tool chain yet, hoping it works for you. Btw, minimum code size for rtl22xx_t is about 16K with 2K .bss/.data space, and the binary removed the filesystem and libc overhead. What is your requirement for RAM and ROM space?<br>
<br>For the assembly code. The cortex family does not need to change to ARM mode when run the privilege instructions. So you can change the mode switch macro like align. Furthermore, cortex adds some registers like basepri, psp which is critical to the thread switch. You will have to add code to handle these.<br>
<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="im"><br>
><br>
> If you have a non-RTEMS "no OS" arm-elf toolset which can<br>
> produce working executables for you, then you are almost<br>
> ready for a very minimal BSP.<br>
><br>
> + Use the linker script as base with additions for<br>
> workspace related symbols<br>
> + Use the crt0.S from it (change call main -> boot_card)<br>
> + implement a polled console using the libgloss support.<br>
> + Use the "dummy idle task clock driver"<br>
<br>
</div>As soon as I can figure the best way to get the score code to<br>
compile that will be my next step, using the rtems supplied tools. :)<br>
<div class="im"><br>
><br>
> At the moment, I think the avr, m32c, adn m32r BSPs are the closest<br>
> examples to this minimal point.<br>
><br>
> That gives you enough to run tests with no interrupts.<br>
><br>
> Sebastian will need to step in for exception processing.<br>
<br>
</div>Waiting to hear from him.<br>
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><br>
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Thanks again,<br>
<font color="#888888">Mike<br>
</font><div><div></div><div class="h5"><br>
><br>
> -- Joel Sherrill, Ph.D. Director of Research & Development<br>
> joel.sherrill@OARcorp.com On-Line Applications Research<br>
> Ask me about RTEMS: a free RTOS Huntsville AL 35805<br>
> Support Available (256) 722-9985<br>
<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>Thanks & Best Regards!<br><br>Ray, Xu <br>PEP Technology<br>