Previously, memories were silently discarded by the JSON backend, making
round-tripping modules with them crash.
Since there are already some users using JSON to implement custom
external passes that use memories (and infer width/size from memory
ports), let's fix this by just making JSON backend and frontend support
memories as first-class objects.
Processes are still not supported, and will now cause a hard error.
Fixes#1908.
As per suggestion made in https://github.com/YosysHQ/yosys/pull/1987, now:
RTLIL::wire holds an is_signed field.
This is exported in JSON backend
This is exported via dump_rtlil command
This is read in via ilang_parser
Fixes#1823.
This will allow nextpnr to reuse the default value information already
present in yosys cells_sim.v and avoid duplicating (and probably
desyncing) this information.
This increases compatibility with certain older parsers in some cases
that worked before commit 15fae357 but do not work with the current
compat-int mode
Before, the rules for encoding parameters in JSON were as follows:
- if the parameter is not a string:
- if it is exactly 32 bits long and there are no z or x bits, emit it
as an int
- otherwise, emit it as a string made of 0/1/x/z characters
- if the parameter is a string:
- if it contains only 0/1/x/z characters, append a space at the end
to distinguish it from a non-string
- otherwise, emit it directly
However, this caused a problem in the json11 parser used in nextpnr:
yosys emits unsigned ints, and nextpnr parses them as signed, using
the value of INT_MIN for values that overflow the signed int range.
This caused destruction of LUT5 initialization values. Since both
nextpnr and yosys parser can also accept 32-bit parameters in the
same encoding as other widths, let's just remove that special case.
The old behavior is still left behind a `-compat-int` flag, in case
someone relies on it.
o Not all derived methods were marked 'override', but it is a great
feature of C++11 that we should make use of.
o While at it: touched header files got a -*- c++ -*- for emacs to
provide support for that language.
o use YS_OVERRIDE for all override keywords (though we should probably
use the plain keyword going forward now that C++11 is established)
Marcelina Kościelnicka
whitequark
Vamsi K Vytla
R. Ou
Clifford Wolf
Miodrag Milanovic
Ben Widawsky
Henner Zeller
Sebastian Kuzminsky
Larry Doolittle