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Cortex A8 Instruction Cycle Timing

Note: This was originally posted on 17th March 2011 at http://forums.arm.com

Hi) sorry for bad English

I need to count latency for two instruction, and all I have is the arm cortex A 8 documantation(charter 16) !
but I have no idea how can do this work using that documantation(

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0 Dung Tran over 12 years ago

Note: This was originally posted on 17th June 2011 at http://forums.arm.com

Hi Estienne.
Thank you very much for your explanation.

for MRS and MSR: there is a lot of instruction that I've not found real cycle timing and I do not have time to test.

Now I understand how hard to find cycle timing for all instructions.
For not found instructions, you treat them as unrecognized, right?
I tried some instructions such as: SETEND, BLKP, SMI, SMC and your cycle count module said unrecognized.

Take the last version (but keep the previous one because I've change a lot of things).

How can I get the lastest version. Is it here: http://pulsar.websha...x-A8-cycle.xlsx
I found some instructions are updated. For example, SUBS pc, lr, #imm isn't in "cortex-A8-cycle.xlsx" but it is available in http://pulsar.websha...ult.php?lng=fr.

For example I remove all the STM and LDM rules. There is to many case. Now I build this rules automaticaly in the cycle counter.

I can't understand why there is too many cases. I guess you calculate how many registers and get how many cycle by the formula in specs.
Please explain for me if you can.
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0 Dung Tran over 12 years ago

Note: This was originally posted on 17th June 2011 at http://forums.arm.com

Hi Estienne.
Thank you very much for your explanation.

for MRS and MSR: there is a lot of instruction that I've not found real cycle timing and I do not have time to test.

Now I understand how hard to find cycle timing for all instructions.
For not found instructions, you treat them as unrecognized, right?
I tried some instructions such as: SETEND, BLKP, SMI, SMC and your cycle count module said unrecognized.

Take the last version (but keep the previous one because I've change a lot of things).

How can I get the lastest version. Is it here: http://pulsar.websha...x-A8-cycle.xlsx
I found some instructions are updated. For example, SUBS pc, lr, #imm isn't in "cortex-A8-cycle.xlsx" but it is available in http://pulsar.websha...ult.php?lng=fr.

For example I remove all the STM and LDM rules. There is to many case. Now I build this rules automaticaly in the cycle counter.

I can't understand why there is too many cases. I guess you calculate how many registers and get how many cycle by the formula in specs.
Please explain for me if you can.
Cancel
Vote up 0 Vote down

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