https://github.com/mhx/libembedded
Modern C++ for Embedded Systems
https://github.com/mhx/libembedded
c-plus-plus c-plus-plus-11 constexpr cpp cpp-library cpp11 embedded embedded-applications embedded-cpp embedded-systems iir-filters mit-license modern-cpp
Last synced: about 2 months ago
JSON representation
Modern C++ for Embedded Systems
- Host: GitHub
- URL: https://github.com/mhx/libembedded
- Owner: mhx
- License: other
- Created: 2021-02-20T17:05:20.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2022-02-18T14:00:49.000Z (over 3 years ago)
- Last Synced: 2025-03-24T05:13:21.576Z (2 months ago)
- Topics: c-plus-plus, c-plus-plus-11, constexpr, cpp, cpp-library, cpp11, embedded, embedded-applications, embedded-cpp, embedded-systems, iir-filters, mit-license, modern-cpp
- Language: C++
- Homepage:
- Size: 1.48 MB
- Stars: 14
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://www.codacy.com/gh/mhx/libembedded/dashboard?utm_source=github.com&utm_medium=referral&utm_content=mhx/libembedded&utm_campaign=Badge_Grade)
# libembedded - Modern C++ for Embedded Systems
This library will hopefully, over time, become a collection of useful,
modern C++ abstractions, with a particular focus on being useful in
the context of embedded systems.
The goal for this library is to provide abstractions that
- work nicely without exceptions and RTTI enabled,
- work nicely without dynamic memory allocation and
- require only C++11 compliant compilers.
# What's inside
## A polymorphic function wrapper with in-place storage
`embedded::function` is loosely modeled after `std::function` and inspired
by both SG14's `inplace_function` and `folly::Function`. It requires no
dynamic memory allocation, but, contrary to `etl::delegate`, is able to
wrap lambdas and other function objects as long as they fit into the
in-place storage.
## A circular buffer adapter
The `circular_buffer_adapter` template allows the construction of circular
buffers on top of a arbitrary, and possibly persistent, memory. This means
that you can easily build circular buffers on top of EEPROM sections.
## Variable length integers
`embedded::varint` implements encoding and decoding of interger values to
and from byte streams, using as few bytes as possible, and independent of
byte order.
## Type traits
A few type traits have been back-ported from later C++ standards. More
will be added on-demand.
## An experimental compile-time IIR filter design library
This library (in `embedded/signal`) can be used to directly design IIR
filters in C++ code without any run-time overhead. This is currently in
experimental state as the interface isn't yet settled and there's quite
a few things that are still missing. However, you can do things like:
```
constexpr auto design =
iirfilter<>(1000.0).lowpass(chebyshev1<8>(3.0), 40.0).sos();
auto filter = design.instance();
for (;;) {
output(filter(input()));
}
```
This will design an 8th-order Chebyshev Type I low-pass filter with
3 dB of passband ripple, a sample rate of 1 kHz and a cutoff frequency
of 40 Hz. All filter coefficients will be determined at compile-time
and the run-time filter code is extremely efficient. For example, this
is the full ARM assembly for the above code, but using a second-order
filter:
```
process():
push {r3, lr}
vpush.64 {d8, d9, d10}
vldr.32 s17, .L5
vldr.32 s20, .L5+4
vldr.32 s19, .L5+8
vmov.f32 s16, s17
vldr.32 s18, .L5+12
.L2:
bl input()
vmul.f32 s13, s0, s20
vmov.f32 s15, s0
vldr.32 s12, .L5+16
vadd.f32 s14, s16, s13
vmul.f32 s16, s14, s18
vmls.f32 s13, s14, s12
vmov.f32 s0, s14
vnmls.f32 s16, s15, s19
vadd.f32 s16, s16, s17
vmov.f32 s17, s13
bl output(float)
b .L2
.L5:
.word 0
.word 1005574271
.word 1013962879
.word -1075339548
.word 1062851613
```
The library is also able to build fixed-point arithmetic filters
if a suitable fixed-point implementation is provided
(e.g. [fpm](https://github.com/MikeLankamp/fpm)).
You can find examples in the `examples` directory of the repo.
## Experimental compile-time math library
This is primarily used by the compile-time filter design library and
currently only contains the minimum functionality needed to implement
the filter design. It does contain things like `constexpr` functions
(provided either via `libstdc++`'s non-standard builtins or via the
[gcem library](https://github.com/kthohr/gcem)), `constexpr` complex
numbers and `constexpr` vectors.