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Honored Contributor I
717 Views

Does using register structs affect timing at all (does fitter keep them together?)

Does declaring a register packed structure affect the layout of the registers? (and therefore timing?) 

 

For example, 

 

typedef struct packed { 

bit [31:0] ntp_time; 

bit [15:0] index; 

bit [15:0] value; 

bit [15:0] tag; 

} _mystruct; 

 

_mystruct table[64]; 

 

Does it matter to the fitter that I grouped all these elements together? Or would it be better to separate them instead: 

reg [63:0][31:0] ntp_time; 

reg [63:0][15:0] index; 

reg [63:0][15:0] value; 

reg [63:0][15:0] tag; 

 

Using data structures helps me stay organized, but I'm trying to find out if it affects my timing.
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Highlighted
Honored Contributor I
4 Views

How you code it will make no difference. It is the register-register timing that matters - and this wont change when you change the code structure.

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