The previous version could easily generate a large amount of padding
when the constant factor was significantly larger than the width of the
shift data input. This could lead to huge amounts of logic being
generated before then being optimized away at a huge performance and
memory cost.
Additionally and more critically, when the input width was not a
multiple of the constant factor, the input data was padded with 'x bits
to such a multiple before interspersing the 'x padding needed to align
the selectable windows to power-of-two offsets.
Such a final padding would not be correct for shifts besides $shiftx,
and the previous version did attempt to remove that final padding at the
end so that the native zero/sign/x-extension behavior of the shift cell
would be used, but since the last selectable window also got
power-of-two padding appended after the padding the code is trying to
remove got added, it did not actually fully remove it in some cases.
I changed the code to only add 'x padding between selectable windows,
leaving the last selectable window unpadded. This omits the need to add
final padding to a multiple of the constant factor in the first place.
In turn, that means the only 'x bits added are actually impossible to
select. As a side effect no padding is added when the constant factor is
equal to or larger than the width of the shift data input, also solving
the reported performance bug.
This fixes#4056
Renamed python script so that it sits next to the testbench file when alphabetically sorted.
Reverted `MAX_WIDTH` to full precision for truncation testing.
Expected values are now stored in full precision rather than truncating to the same value as the input.
i.e. 0x5a5a5a5a will truncate to 0x5a5a for write data but will remain 0x5a5a5a5a for expected read.
Adds TDP submodule to generator.
Adds shorthand expected signal to testbench (mostly to make it easier when I look at the vcd dump to figure out what I did wrong in tests).
Adds `double_sync_ram_sdp` to `common/blockram.v`, providing a test for two disjoint memories.
Refactor python blockram template to take a list of params to support the above.
Also change the smaller single TDP36K tests to also test `port_a_width` value.
Use python script to generate tests for both SDP and TDP across multiple sizes of RAM.
Adds sync_ram_sdp_(wwr|wrr) to common blockram.v for double width write and double width read respectively.
In preparation for substantial expansion of CXXRTL's runtime, this commit
reorganizes the files used by the implementation. Only minimal changes are
required in a consumer.
First, change:
-I$(yosys-config --datdir)/include
to:
-I$(yosys-config --datdir)/include/backends/cxxrtl/runtime
Second, change:
#include <backends/cxxrtl/cxxrtl.h>
to:
#include <cxxrtl/cxxrtl.h>
(and do the same for cxxrtl_vcd.h, etc.)
This expands the part-select tests with one additional module.
It specifically tests the different variants of the `peepopt`
optimizations `shiftadd` and `shiftmul`.
Not all these cases are actually transformed using `shiftadd`,
including them also checks if the correct variants are rejected.
- Add support for assignments within expressions, e.g., `x[y++] = z;` or
`x = (y *= 2) - 1;`. The logic is handled entirely within the parser
by injecting statements into the current procedural block.
- Add support for pre-increment/decrement statements, which are
behaviorally equivalent to post-increment/decrement statements.
- Fix non-standard attribute position used for post-increment/decrement
statements.
Jannis Harder
Martin Povišer
Krystine Sherwin
N. Engelhardt
Catherine
Lofty
phsauter
Zachary Snow
andyfox-rushc
Miodrag Milanovic