TMS320C6678: Y<- Y+AxB calculation

Hitoshi Sugawara

Mastermind 19960 points

Part Number: TMS320C6678

Hi Experts,

According to the application note FSPRUGH7, Fixed point 16x16 MACs per cycle is 32.

Let me clarify whether 32 of "Y<- Y+AxB" can be done at one cycle or not.
If not, please let me know how many calculation could be done at one cycle.

Thank you and best regards,
Hitoshi

over 5 years ago

0 lding over 5 years ago

TI__Guru* 95265 points

Hi,

Sorry for the late response. In my belief, MAC means Multiply-Accumulate. However, I looked those instructions in TMS320C66x DSP Literature Number: SPRUGH7 November 2010 CPU and Instruction Set, I didn't find out how to do multiply and addition in the same cycle. I am still checking that.

Regards, Eric

0 lding over 5 years ago in reply to lding

TI__Guru* 95265 points

Hi,

You need one cycle for the multiply, then another cycle for the addition.

Regards, Eric

0 Hitoshi Sugawara over 5 years ago in reply to lding

TI__Mastermind 19960 points

Hi Eric,

Thank you for your info.
Let me clarify the exact cycles for 32 of "Y<- Y+AxB".

Is it done with 1 cycle (32 of MACs) + 1 cycle for the multiply+ 1 cycle for addition = 3 cycles for 32 of "Y<- Y+AxB"?

Am I making sense?

Thank you for you double check.
Best regards,

Hitoshi

0 lding over 5 years ago in reply to Hitoshi Sugawara

TI__Guru* 95265 points

Hi,

No, it is 1 cycles of 32 of MACs (this is the multiply) + 1 cycle of addition.

Regards, Eric

0 Hitoshi Sugawara over 5 years ago in reply to lding

TI__Mastermind 19960 points

Hi Eric,

Thank you for the cycles.
I understood.

Best regards,

Hitoshi

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TMS320C6678: Y<- Y+AxB calculation