how to use #pragma for memory allocation in c6670

satya phani tej nittala

Other Parts Discussed in Thread: CCSTUDIO

hi all,

i am using c6670 multicore dsp. for writing the c code i am using ccstudio v5.5. I have a look up table of size 65536. i want to keep it in the ram . so i tried,

unsigned int ctab[65536];

#pragma DATA_ALIGN(ctab, 128);

#pragma DATA_SECTION(ctab, ".edma_ddr");

But error occured when i tried to build it

error #10099-D: program will not fit into available memory. run placement with alignment fails for section ".sysmem" size 0x1dcd6500

how to use pragma for memories?

over 10 years ago

0 one and zero over 10 years ago

TI__Mastermind 18136 points

Hi,

the pragma's need to be in front of the
unsigned int ctab[65536];
line.

Are you referring .edma_ddr in the linker command file?

Kind regards,
one and zero

0 satya phani tej nittala over 10 years ago in reply to one and zero

Prodigy 190 points

NO I'M NOT REFERRING TO THEM. to prevent further errors in the future, how to use pragma, and which section of memory should i use. please help me.

regards
phani tej

0 one and zero over 10 years ago in reply to satya phani tej nittala

TI__Mastermind 18136 points

You need to refer you're generated section .edma_ddr

E.G.:

MEMORY
{

L2_MEM: origin = 0x00800000 length = 0x00080000 /* This is for local SRAM, could be used as cache. */

SL2: origin = 0x0C000000 length = 0x0040000

DDR3: origin = 0x80000000 length = depending on the size of your DDR3 memory
}
SECTIONS
{
vectors > VECS
.text > PMEM
.data > BMEM
.stack > BMEM
.bss > BMEM
.sysmem > BMEM
.cinit > BMEM
.const > BMEM
.cio > BMEM
.far > BMEM
.edma_ddr > DDR3
}

Kind regards,
one and zero

0 satya phani tej nittala over 10 years ago in reply to one and zero

Prodigy 190 points

can i directly refer to SHRAM or LOCAL_L2_SRAM instead of .edma_ddr. If yes, how?

one more question is , will there be any difference in the number of machine cycles taken by the processor for fetch operation when using SHRAM and LOCAL_L2_SRAM

0 one and zero over 10 years ago in reply to satya phani tej nittala

TI__Mastermind 18136 points

No you can't directly map into a memory location. You need to go through the linker command file.

for performance figures please check the Throughput Performance Guide for C66x KeyStone Devices

Kind regards,

one and zero

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how to use #pragma for memory allocation in c6670