diff options
| author | whitequark <whitequark@whitequark.org> | 2020-12-21 02:15:55 +0000 |
|---|---|---|
| committer | whitequark <whitequark@whitequark.org> | 2020-12-21 02:20:34 +0000 |
| commit | b9721bedf01ca1f536bbf13ba761333c6867bd29 (patch) | |
| tree | 5a262c642e0f07230fc81cc7a1a39344603a77a3 /backends/cxxrtl/cxxrtl.h | |
| parent | 40ca9d038b1e657b9b9ac17e7e5a2969c9922e00 (diff) | |
| download | yosys-b9721bedf01ca1f536bbf13ba761333c6867bd29.tar.gz yosys-b9721bedf01ca1f536bbf13ba761333c6867bd29.tar.bz2 yosys-b9721bedf01ca1f536bbf13ba761333c6867bd29.zip | |
cxxrtl: speed up bit repeats (sign extends, etc).
On Minerva SoC SRAM, depending on the compiler, this change improves
overall time by 4-7%.
Diffstat (limited to 'backends/cxxrtl/cxxrtl.h')
| -rw-r--r-- | backends/cxxrtl/cxxrtl.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/backends/cxxrtl/cxxrtl.h b/backends/cxxrtl/cxxrtl.h index 3c315c7df..0a6bcb849 100644 --- a/backends/cxxrtl/cxxrtl.h +++ b/backends/cxxrtl/cxxrtl.h @@ -317,6 +317,14 @@ struct value : public expr_base<value<Bits>> { return sext_cast<NewBits>()(*this); } + // Bit replication is far more efficient than the equivalent concatenation. + template<size_t Count> + CXXRTL_ALWAYS_INLINE + value<Bits * Count> repeat() const { + static_assert(Bits == 1, "repeat() is implemented only for 1-bit values"); + return *this ? value<Bits * Count>().bit_not() : value<Bits * Count>(); + } + // Operations with run-time parameters (offsets, amounts, etc). // // These operations are used for computations. |