For more pessimistic power propagation for combinational circuits, the user should be able to enable a mode assume signals can switch on both posedge and negedge of the relevant clock.
For example, consider a NAND2 Z=!(AB) with density(A)=density(B)=0.5 toggles/cycle, duty(A)=0.5.
Assuming A, B, and Z can toggle only on the posedge clock should give a density(Z)=0.375.
Assuming they can toggle on either posedge or negedge gives a density(Z)=0.4375 according to:
- The clock toggles twice in each cycle
- For any given edge, the probability of A or B switching is 0.25, and all signals are equally likely.
- There are 6 possible transitions out of 16 where Z where the probability of each transition is given below for a sum of 0.21875
00 to 11 | 0.5*0.5*0.25*0.25 = 0.015625
01 to 11 | 0.5*0.5*0.25*0.75 = 0.046875
10 to 11 | 0.046875
11 to 00 | 0.015625
11 to 01 | 0.046875
11 to 10 | 0.046875
- For a given cycle, there are two chances for a transition so the density of Z is 2 * 0.21875 = 0.4375
This issue is to add a command where the user can switch propagation to the 2nd mode described above.
For more pessimistic power propagation for combinational circuits, the user should be able to enable a mode assume signals can switch on both posedge and negedge of the relevant clock.
For example, consider a NAND2 Z=!(AB) with density(A)=density(B)=0.5 toggles/cycle, duty(A)=0.5.
Assuming A, B, and Z can toggle only on the posedge clock should give a density(Z)=0.375.
Assuming they can toggle on either posedge or negedge gives a density(Z)=0.4375 according to:
This issue is to add a command where the user can switch propagation to the 2nd mode described above.