# neoh
NeoH (or NeoHDL) is a declarative HDL, proficient in creating extremely fast and secure testbenches, with complete support for SystemVerilog, as it transpiles into said HDL.
## Features
• Modular "blocks", improves on "modules" in SystemVerilog:
```SystemVerilog
block Example(in a, in b, out c) logic {
ret tempassign c [always 7:0] <= a + b;
}
// NOTE tempassign assign a value to a variable for only that block. The [always MSB:LSB] identifier can be assigned to either the result, or expression.
```
• Improves on "interfaces":
```SystemVerilog
piece ExampleBus {
in addr, in data, out ready
}
pieced block Example(ExampleBus <= bus){}
```
• Improved hierarchy support:
```SystemVerilog
block top(in x, in y, out z) logic {
n1 passparams example(x,y,z);
ret z <= n1;
}
```
• Easier macros with "known":
```SystemVerilog
known macro1 <= clk, rst;
// pass into block
block macroeater(in clk, in rst) {}
```
• Testbenches are easier now:
```SystemVerilog
testbench random target(RandomBlock){
getvars(signal1, signal2, !signal3, clk, rst);
// "!" before a var (in getvars) indicates it should never be included, if, for example, "*" is passed as an argument (which means "all")
when(BEGIN){
put signal1 <= 1;
/10 expect(signal2 == 1);
pulse len(clk), gap(rst);
/50 watchfor req <= ack & /100 out(status);
writefile(mode vcd, file output.vcd);
}
}
```
• Along with "testgroups":
```SystemVerilog
testgroup ExampleGroup {
do tb_random;
same {
tb1
tb2
} // "same" = synchronous running;
}
```
• Typing "always_ff" is easier now 🙃:
```SystemVerilog
aff posedge(clk) or negedge(rst) {}
```
# In Conclusion...
• It provides a more declarative way to write testbenches.
• No more boilerplate code with complex hierarchies.
• And more modular syntax.
## Installation
Ensure you have [Rust/Cargo](https://rustup.rs/) installed.
```bash
cargo install neoh
```
## Quick Start
Create a file called main.neoh:
```SystemVerilog
// main.neoh
block Example(in a, in b, out c) logic {
ret c <= a + b;
}
testbench Verification target(Example) {
getvars(a, b, c);
when(BEGIN) {
put a <= 1;
put b <= 2;
/100 out("Hello Neo!");
}
}
```
Compile it:
```bash
neoh simple.neoh
# Generates simple.sv
```
# Contributing
We welcome contributions! Please fork the repository and submit a pull request.
1. Run
`cargo test`
to ensure changes pass.
2. Add tests for new features in `/tests`.