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
For SVAs that have an explicit clock and are contained in a procedure
which conditionally executes the assertion, verific expresses this using
a mux with one input connected to constant 1 and the other output
connected to an SVA_AT. The existing code only handled the case where
the first input is connected to 1. This patch also handles the other
case.
The `-keepdc` option prevents merging flipflops with dont-care bits in
their initial value, as, in general, this is not a valid transform for
formal verification.
The keepdc option of `opt` is passed along to `opt_merge` now.
- Prevent unmatched expected error patterns from self-matching
- Prevent infinite recursion on unmatched expected warnings
- Always print the error message for unmatched error patterns
- Add test coverage for all unmatched message types
- Add test coverage for excess matched logs and warnings
Anlogic FPGAs all have two kinds of BRAMs, one is 9bit*1K when being
true dual port (or 18bit*512 when simple dual port), the other is
16bit*2K.
Supports mapping of these two kinds of BRAMs. 9Kbit BRAM in SDP mode and
32Kbit BRAM with 8bit width are not support yet.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
The preprocessor currently destroys double slash containing escaped
identifiers (for example \a//b ). This is due to next_token trying to
convert single line comments (//) into /* */ comments. This then leads
to an unintuitive error message like this:
ERROR: syntax error, unexpected '*'
This patch fixes the error by recognizing escaped identifiers and
returning them as single token. It also adds a testcase.
