AM5728: PRU assembler instructions

Sung-IL

Part Number: AM5728

Dear Champs,

Could you please let me know where is document explain AM57x PRU assembler instructions?

I informed below url already, but my customer complain that it seems new instructions like MPY for PRUv3(AM57x/AM335x) are not fully listed is not listed.

http://processors.wiki.ti.com/index.php/PRU_Assembly_Instructions

e.g. my customer find some new instructions like MPY introduced in PRU v3 and don't know how he can use it.

Could you please let me know where the full PRU assembly instructions are listed?

Thanks and Best Regards,

SI.

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

The PRU experts have been notified. They will respond here.

0 Rogerio Almeida over 9 years ago in reply to Biser Gatchev-XID

TI__Mastermind 26215 points

Did you check this link?
processors.wiki.ti.com/.../PRU-ICSS_Migration_Guide:_AM335x_to_AM57x
there is another one if they have used AM437x before...
processors.wiki.ti.com/.../PRU-ICSS_Migration_Guide:_AM437x_to_AM57x
And for HW comparisons..
processors.wiki.ti.com/.../PRU-ICSS_Feature_Comparison

0 Sung-IL over 9 years ago in reply to Rogerio Almeida

TI__Mastermind 31220 points

Yes. of course.

what he want is to know assembler instructions and its details - descriptions and examples - to develop SW.
He should use assembly language in his PRU SW, but could not find any documents describing new assembly instructions for PRU v3.

Thanks and Best Regards,
SI.

0 Jason Reeder over 9 years ago in reply to Sung-IL

TI__Genius 10440 points

Please see section 30.1.5.3 in the AM5728 Technical Reference Manual (http://www.ti.com/lit/spruhz6). This section explains the MAC block in the PRU subsystem and also shows which registers must be loaded in order to use it.

That being said, there is no MPY instructions in the PRU instruction set. Registers R25-R29 are used to pass operands and results between the PRU core and the MAC block.

There is a C code example in the PRU Software Support Package that utilizes the MAC block for a multiply/accumulate loop (git.ti.com/.../PRU_MAC_Multiply_Accum). The C compiler recognizes the code could benefit from the use of the external MAC block and then generates the necessary instructions (using register R25-R29) to do so.

It is recommended that the C compiler be used if at all possible. But, if the customer would like to write assembly code then they can look at the generated assembly (from the C compiler) as an example on how to use the MAC block. The -k flag used during compile time will keep the generated assembly file and will be stored with the .asm file extension.

Jason Reeder

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AM5728: PRU assembler instructions