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The previously generated logic assumed an unconstrained past value in the initial state and did not handle 'x values. While the current formal verification flow uses 2-valued logic, SVA value change expressions require a past value of 'x during the initial state to behave in the expected way (i.e. to consider both an initial 0 and an initial 1 as $changed and an initial 1 as $rose and an initial 0 as $fell). This patch now generates logic that at the same time a) provides the expected behavior in a 2-valued logic setting, not depending on any dont-care optimizations, and b) properly handles 'x values in yosys simulation |
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| .. | ||
| .gitignore | ||
| basic00.sv | ||
| basic01.sv | ||
| basic02.sv | ||
| basic03.sv | ||
| basic04.sv | ||
| basic04.vhd | ||
| basic05.sv | ||
| basic05.vhd | ||
| counter.sv | ||
| extnets.sv | ||
| Makefile | ||
| runtest.sh | ||
| sva_not.sv | ||
| sva_range.sv | ||
| sva_throughout.sv | ||
| sva_value_change_changed.sv | ||
| sva_value_change_rose.sv | ||
| sva_value_change_sim.sv | ||
| sva_value_change_sim.ys | ||