Stack allocation

Antoine Mignon

Other Parts Discussed in Thread: HALCOGEN

Hello,

I'm running some performance test on the TMS570LS3137HDK. I managed to execute benchmarks from SDRAM with the code sections, data, bss and sysmem in the SDRAM. The next step is to put the stack in the SDRAM.

However, HalcoGen (03.02.02) does not allow me to configure the stack as I want. I tried to modify the linker command file (see below) without success.

--retain="*(.intvecs)"
--heap_size=0x80000
--stack_size=0x80000

/*----------------------------------------------------------------------------*/
/* Memory Map                                                                 */

MEMORY
{
    VECTORS (X)  : origin=0x00000000 length=0x00000020
    FLASH0  (RX) : origin=0x00000020 length=0x0017FFE0
    FLASH1  (RX) : origin=0x00180000 length=0x00180000
    STACKS  (RW) : origin=0x80000000 length=0x00080000
    RAM     (RW) : origin=0x08000000 length=0x00040000


    SDRAM1  (RWX): origin=0x80080000 length=0x0017FFFF
    SDRAM2  (RWX): origin=0x80200000 length=0x001FFFFF
    SDRAM3  (RWX): origin=0x80400000 length=0x001FFFFF
    SDRAM4  (RWX): origin=0x80600000 length=0x001FFFFF
}

/*----------------------------------------------------------------------------*/
/* Section Configuration                                                      */

SECTIONS
{
    .intvecs : {} > VECTORS
    .text    : {} > FLASH0 | FLASH1
    .const   : {} > FLASH0 | FLASH1
    .cinit   : {} > FLASH0 | FLASH1
    .pinit   : {} > FLASH0 | FLASH1
    .bss     : {} > SDRAM1
    .data    : {} > SDRAM1
    .stack   : {} > STACKS
    .sysmem  : {} > SDRAM1

   .sdram_section2 : RUN = SDRAM2, LOAD = FLASH0|FLASH1, TABLE(BINIT)
   .sdram_section3 : RUN = SDRAM3, LOAD = FLASH0|FLASH1, TABLE(BINIT)
   .sdram_section4 : RUN = SDRAM4, LOAD = FLASH0|FLASH1, TABLE(BINIT)
}

Is there any way to put the stack in the SDRAM ?

Regards,

Antoine

over 9 years ago

0 Anthony F. Seely over 9 years ago

TI__Guru 68920 points

Antoine,

you could change:

.stack   : {} > STACKS

to

    .stack   : {} > SDRAM


for more information see the linker documentation




but i would not recommend this.  the external SDRAM is not protected by ECC and access time is much slower.

-Anthony

0 Antoine Mignon over 9 years ago in reply to Anthony F. Seely

Prodigy 140 points

Hi Anthony,

STACKS has its origin in the SDRAM (0x8000000). So my linker configuration should be compliant with your answer. According to the linker documentation .stack section should appear in the segment allocation map but it does not.

I know about the bad performance that will come with putting the stack in the SDRAM. I want to evaluate the drop of performance.

My CCS project is in the attached archive.

Regards,

Antoine

6131.ti_perf_meas.zip

0 Anthony F. Seely over 9 years ago in reply to Antoine Mignon

TI__Guru 68920 points

Good point - missed that.

sys_core.asm seems to be controlling the location of the stack:

;-------------------------------------------------------------------------------
; Initialize Stack Pointers

.def _coreInitStackPointer_
.asmfunc

_coreInitStackPointer_

cps #17
ldr sp, fiqSp
cps #18
ldr sp, irqSp
cps #23
ldr sp, abortSp
cps #27
ldr sp, undefSp
cps #31
ldr sp, userSp
cps #19
ldr sp, svcSp
bx lr

userSp .word 0x08000000+0x00001000
svcSp .word 0x08000000+0x00001000+0x00000100
fiqSp .word 0x08000000+0x00001000+0x00000100+0x00000100
irqSp .word 0x08000000+0x00001000+0x00000100+0x00000100+0x00000100
abortSp .word 0x08000000+0x00001000+0x00000100+0x00000100+0x00000100+0x00000100
undefSp .word 0x08000000+0x00001000+0x00000100+0x00000100+0x00000100+0x00000100+0x00000100

I tried changing the "RAM Base Address" on the <device>->RAM tab but this seems to be fixed.
So you would need to override this by manually editing the sys_core.asm file.

You can make a copy of the file w. a different name for now and exclude the generated file from the build.
(Because the user code comments do not appear in C).
I'll submit a ticket on the issue but it's a bit unusual of a use case IMO as this isn't really
how the part is designed to operate.

0 Anthony F. Seely over 9 years ago in reply to Anthony F. Seely

TI__Guru 68920 points

Antoine,

Did you change this section and get it to work? Here's the ticket number SDOCM00122164 still showing as just submitted.

0 Antoine Mignon over 9 years ago in reply to Anthony F. Seely

Prodigy 140 points

Hi Anthony,

As the EMIF is initialized using the stack it is not possible to change the address of the stack pointers before the init is done. But if the addresses are changed after it works.

Based on _coreInitStackPointer_, I have added a function in sys_core.asm to modify the stack addresses (see below). This function is called between the end of the initialization and the call of the main() application :

    .def     _coreSetStackPointerInSDRAM_
    .asmfunc

_coreSetStackPointerInSDRAM_

        cps   #17
        ldr   sp,       fiqSpSDRAM
        cps   #18
        ldr   sp,       irqSpSDRAM
        cps   #23
        ldr   sp,       abortSpSDRAM
        cps   #27
        ldr   sp,       undefSpSDRAM
        cps   #31
        ldr   sp,       userSpSDRAM
        cps   #19
        ldr   sp,       svcSpSDRAM
        bx    lr

userSpSDRAM  .word 0x80000000
svcSpSDRAM   .word 0x80000000+0x0007FB00
fiqSpSDRAM   .word 0x80000000+0x0007FB00+0x00000100
irqSpSDRAM   .word 0x80000000+0x0007FB00+0x00000100+0x00000100
abortSpSDRAM .word 0x80000000+0x0007FB00+0x00000100+0x00000100+0x00000100
undefSpSDRAM .word 0x80000000+0x0007FB00+0x00000100+0x00000100+0x00000100+0x00000100

    .endasmfunc

Thanks for your help.

Antoine

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Stack allocation