On 21/10/20 4:51 pm, Sebastian Huber wrote:
> On 21/10/2020 07:42, Chris Johns wrote:
>
>> On 21/10/20 4:31 pm, Sebastian Huber wrote:
>>> On 21/10/2020 02:25, Chris Johns wrote:
>>>
>>>> On 21/10/20 3:04 am, Sebastian Huber wrote:
>>>>> ---
>>>>> bsps/arm/shared/start/linkcmds.base | 4 ++--
>>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/bsps/arm/shared/start/linkcmds.base
>>>>> b/bsps/arm/shared/start/linkcmds.base
>>>>> index d0663cf97e..8fa127ce08 100644
>>>>> --- a/bsps/arm/shared/start/linkcmds.base
>>>>> +++ b/bsps/arm/shared/start/linkcmds.base
>>>>> @@ -290,7 +290,7 @@ SECTIONS {
>>>>> .fast_text : ALIGN_WITH_INPUT {
>>>>> bsp_section_fast_text_begin = .;
>>>> What is `fast text` (and fast data)? I have not heard of this before and I
>>>> cannot find anything on it?
>>> I added this section 11 years ago as a section for code which could reside
>>> in a
>>> faster memory. For example, normal code could reside on a 16-bit SDRAM and
>>> the
>>> fast code on an internal 32-bit SRAM in a chip without a cache. In the
>>> recent
>>> Cortex-M7 BSPs, the fast text is mapped to the ITCM.
>> OK. Is anything written up about this?
> No, maybe we should add something about this in the arm BSP section of the
> user
> manual.
That would be helpful.
>> For example is allocating variables
>> automatic or can I control allocation to it?
>
> You just have to place a function or variable with the section attribute into
> these sections:
>
> bsps/arm/include/bsp/linker-symbols.h:#define BSP_FAST_TEXT_SECTION \
> bsps/arm/include/bsp/linker-symbols.h- RTEMS_SECTION(".bsp_fast_text")
>
> bsps/arm/include/bsp/linker-symbols.h:#define BSP_FAST_DATA_SECTION \
> bsps/arm/include/bsp/linker-symbols.h- RTEMS_SECTION(".bsp_fast_data")
I think would be good to document otherwise no one will know it exists or how it
can be used.
Chris
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