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The-OpenROAD-Project / OpenSTA

OpenSTA engine
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set_input_transition -clock not supported #4

Closed kunalg123 closed 5 years ago

kunalg123 commented 5 years ago

Hi In some of our constraints file, we have below constraint 1) set_input_transition -clock clk -min -rise 102 [get_ports mem_rdata0 ]

But instead, openSTA uses below 2) set_input_transition -min -rise 102 [get_ports mem_rdata0 ]

While using 1) OpenSTA gives an error that -clock option not supported. Any reason? We wanted to keep consistent SDC constraints across different tools for benchmarking and evaluation. Can you please let know your thoughts?

jjcherry56 commented 5 years ago

set_input_delay -clock is supported. If you have a testcase that show otherwise you should submit it.

jjcherry56 commented 5 years ago

Note that the title of the issue does not match the command in the body of the issue. set_input_transition -clock is not supported. It is basically meaningless because transition times are merged. Separate transition times are not used for each clock in delay calculation.

kunalg123 commented 5 years ago

set_input_delay -clock is supported. If you have a testcase that show otherwise you should submit it.

--> kunalg123 - Thanks James. set_input_delay is supported. I meant set_input_transition

Note that the title of the issue does not match the command in the body of the issue. set_input_transition -clock is not supported. It is basically meaningless because transition times are merged. Separate transition times are not used for each clock in delay calculation.

--> kunalg123 - Title and body corrected. Actually, you are right regarding set_input_transition, and prior to using this, I was using set_driving_cell for IO's I was referring to below SDC document snippet to define constraints, tried setting set_input_transition for saw ports and saw this issue. Do you want to re-check on this constraint definition from Synopsys? Or shall i close this issue? (Please let me know if you are able to see the attachment)

set_input_transition_definition

kunalg123 commented 5 years ago

Hi James Did you had a chance to look into the syntax? Do you want me to close this issue?

jjcherry56 commented 5 years ago

I understand the syntax. Using the -clock argument is meaningless with graph based delay calculation so it flagged as unsupported. If you omit it you will get the same result,

On Saturday, November 10, 2018, kunalg123 notifications@github.com wrote:

Hi James Did you had a chance to look into the syntax? Do you want me to close this issue?

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