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| author | Xiretza <xiretza@xiretza.xyz> | 2020-04-08 19:30:47 +0200 |
|---|---|---|
| committer | Xiretza <xiretza@xiretza.xyz> | 2020-05-28 22:59:03 +0200 |
| commit | 17163cf43a6b6eec9aac44f6a4463dda54b8ed68 (patch) | |
| tree | 02dd1e144c36eb40565cbb792726c7d8d4573eb4 /backends/smv | |
| parent | 0d99522b3c2ca2502129110e09f9988874e37abc (diff) | |
| download | yosys-17163cf43a6b6eec9aac44f6a4463dda54b8ed68.tar.gz yosys-17163cf43a6b6eec9aac44f6a4463dda54b8ed68.tar.bz2 yosys-17163cf43a6b6eec9aac44f6a4463dda54b8ed68.zip | |
Add flooring modulo operator
The $div and $mod cells use truncating division semantics (rounding
towards 0), as defined by e.g. Verilog. Another rounding mode, flooring
(rounding towards negative infinity), can be used in e.g. VHDL. The
new $modfloor cell provides this flooring modulo (also known as "remainder"
in several languages, but this name is ambiguous).
This commit also fixes the handling of $mod in opt_expr, which was
previously optimized as if it was $modfloor.
Diffstat (limited to 'backends/smv')
| -rw-r--r-- | backends/smv/smv.cc | 5 | ||||
| -rw-r--r-- | backends/smv/test_cells.sh | 4 |
2 files changed, 5 insertions, 4 deletions
diff --git a/backends/smv/smv.cc b/backends/smv/smv.cc index 7113ebc97..2fc7099f4 100644 --- a/backends/smv/smv.cc +++ b/backends/smv/smv.cc @@ -358,7 +358,8 @@ struct SmvWorker continue; } - if (cell->type.in(ID($div), ID($mod))) + // SMV has a "mod" operator, but its semantics don't seem to be well-defined - to be safe, don't generate it at all + if (cell->type.in(ID($div)/*, ID($mod), ID($modfloor)*/)) { int width_y = GetSize(cell->getPort(ID::Y)); int width = max(width_y, GetSize(cell->getPort(ID::A))); @@ -366,7 +367,7 @@ struct SmvWorker string expr_a, expr_b, op; if (cell->type == ID($div)) op = "/"; - if (cell->type == ID($mod)) op = "mod"; + //if (cell->type == ID($mod)) op = "mod"; if (cell->getParam(ID::A_SIGNED).as_bool()) { diff --git a/backends/smv/test_cells.sh b/backends/smv/test_cells.sh index 63de465c0..ae832ce00 100644 --- a/backends/smv/test_cells.sh +++ b/backends/smv/test_cells.sh @@ -7,8 +7,8 @@ mkdir -p test_cells.tmp cd test_cells.tmp # don't test $mul to reduce runtime -# don't test $div and $mod to reduce runtime and avoid "div by zero" message -../../../yosys -p 'test_cell -n 5 -w test all /$alu /$fa /$lcu /$lut /$macc /$mul /$div /$mod' +# don't test $div/$mod/$modfloor to reduce runtime and avoid "div by zero" message +../../../yosys -p 'test_cell -n 5 -w test all /$alu /$fa /$lcu /$lut /$macc /$mul /$div /$mod /$modfloor' cat > template.txt << "EOT" %module main |