The semantics of an RTLIL constant that has less bits than its
declared bit width is zero padding. Therefore, if the output of
memory_collect will be used for simulation, truncating 'x from
the end of \INIT will produce incorrect simulation results.
As the TD tool doesn't accept the DRAM cell to contain unknown values in
the initial value, the initialzation support of DRAM is previously
skipped.
Now add the support by add a new pass to determine unknown values in the
initial value.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
During the addition of DRAM inferring support, the installation of
eagle_bb.v is accidentally removed.
Fix this issue.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
According to the datasheet of Anlogic Eagle FPGAs, The LUTs natively
in an Anlogic FPGA is LUT4 (in MSLICEs) and "Enhanced LUT5" (in
LSLICEs). An "Enhanced LUT5" can be divided into two LUT4s.
So a LUT5 will cost around 2x resource of a LUT4, and a LUT6 will cost
2x resource of a LUT5.
Change the -lut parameter passed to the abc command to pass this cost
info to the ABC process.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
As dffinit has already supported for different initialization strings
for DFFs and check for re-initialization, initialization of Anlogic
DFFs are now ready to go.
Support for set the init values of Anlogic DFFs.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Sometimes the FF cell might be initialized during the map process, e.g.
some FPGA platforms (Anlogic Eagle and Lattice ECP5 for example) has
only a "SR" pin for a FF for async reset, that resets the FF to the
initial value, which means the async reset value should be set as the
initial value. In this case the DFFINIT pass shouldn't reinitialize it
to a different value, which will lead to error.
Add a "-noreinit" parameter for the safeguard. If a FF is not
technically initialized before DFFINIT pass, the default value should be
set to x.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
On some platforms the string to initialize DFF might not be "high" and
"low", e.g. with Anlogic TD it's "SET" and "RESET".
Add a "-strinit" parameter for dffinit to allow specify the strings used
for high and low.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
The dbits of DRAM16X4 is wrong set to 2, which leads to waste of DRAM
bits.
Fix the dbits number in the RAM configuration.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
The MSLICEs on the Eagle series of FPGA can be configured as Distributed
RAM.
Enable to synthesis to DRAM.
As the Anlogic software suite doesn't support any 'bx to exist in the
initializtion data of DRAM, do not enable the initialization support of
the inferred DRAM.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
This reverts commit 43030db5ff.
For a synthesis tool, generating EG_LOGIC cells are a good choice, as
they can be furtherly optimized when PnR, although sometimes EG_LOGIC is
not as blackbox as EG_PHY cells (because the latter is more close to the
hardware implementation).
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Clifford Wolf
Larry Doolittle
Icenowy Zheng
whitequark
David Shah
makaimann