Module fst_export 

Exporting the currently displayed variables to an FST waveform file.

Only the displayed variables (and only the hierarchy needed to reach them, not the full design hierarchy) are written out.

Structs

FstExportData 🔒

A self-contained snapshot of everything needed to write a set of variables (and only the hierarchy needed to reach them) to an FST file.

FstExportNode 🔒

A single node of the minimal scope tree needed to export a set of variables to FST.

Enums

FstExport 🔒

Backend-agnostic, owned snapshot of the data needed to write signals out to an FST file.

Functions

common_power_of_ten 🔒

Finds the largest power of ten that evenly divides every non-zero time stamp t in times. This tells us how much coarser than the source’s declared timescale the export’s timescale exponent can be (i.e. closer to zero) while still representing every required time stamp as an exact integer.

fst_scope_type 🔒

Maps a wellen scope type to its FST equivalent.

fst_var_direction 🔒

Maps a wellen variable direction to its FST equivalent.

fst_var_type 🔒

Maps a wellen variable type to its FST equivalent.

scale_time 🔒

Rescales a raw time stamp from the source’s timescale to the export’s timescale, given the precomputed divisor 10.pow(time_scale_shift) (see common_power_of_ten).

trailing_zeros_base10 🔒

Counts how many trailing (decimal) zeros n has, i.e. the largest k for which 10^k divides n evenly. n must be non-zero: 0 is a multiple of every power of ten, which would loop forever. Callers filter out zero time stamps beforehand.

write_fst_export_node 🔒

Recursively declares node’s scopes and variables in the FST header.

write_fst_export_var 🔒

Declares a single variable in the FST header, reusing an existing signal id if the same signal was already declared under a different variable name (aliasing).