start plumbing process blocks

doc/examples/clockdiv.fut

@@ -0,0 +1,12 @@
+module clockdiv_2 (
+	input wire clk,
+	input wire rst,
+	output wire out_clk
+) {
+	proc (clk) {
+		match (rst) {
+			0 => out_clk = 0,
+			1 => out_clk = ~out_clk,
+		}
+	}
+}

src/frontend.rs

@@ -135,11 +135,12 @@ pub fn lower_module(pa_module: parser::Module) -> Result<String, CompileError> {
         );
         ir_module.add_wire(wire);
     }
-    for stmt in pa_module.statements {
-        match stmt {
-            parser::Statement::Assign(assignment) => {
+    for item in pa_module.items {
+        match item {
+            parser::ModuleItem::Assign(assignment) => {
                 lower_assignment(&context, &mut ir_module, assignment)?
             }
+            parser::ModuleItem::Proc(proc) => todo!("lowering process")
         }
     }
     ir_module.write_rtlil(&mut writer);

src/main.rs

@@ -8,6 +8,7 @@ use std::fs::File;
 use std::io::prelude::*;
 use std::path::PathBuf;
 use structopt::StructOpt;
+use nom::error::convert_error;
 
 #[derive(Debug, StructOpt)]
 #[structopt(name = "example", about = "An example of StructOpt usage.")]
@@ -28,9 +29,10 @@ fn main() {
     let input = parser::Span::new(input);
     let parsed = parser::parse(input);
     match parsed {
-        Err(nom::Err::Error(_err) | nom::Err::Failure(_err)) => {
-            // TODO: get this working again
-            // print!("{}", convert_error(input, err))
+        Err(nom::Err::Error(err) | nom::Err::Failure(err)) => {
+            // TODO: get pretty errors again
+            // print!("{}", convert_error(*input, err))
+            print!("{}", err);
         }
         Err(_) => (),
         Ok(res) => {

src/parser.rs

@@ -66,12 +66,37 @@ pub struct PortDecl<'a> {
 pub struct Module<'a> {
     pub name: &'a str,
     pub ports: Vec<PortDecl<'a>>,
-    pub statements: Vec<Statement<'a>>,
+    pub items: Vec<ModuleItem<'a>>,
 }
 
 #[derive(Debug)]
-pub enum Statement<'a> {
+pub enum ModuleItem<'a> {
     Assign(Assign<'a>),
+    Proc(ProcBlock<'a>),
+}
+
+#[derive(Debug)]
+pub struct ProcBlock<'a> {
+    pub net: Span<'a>,
+    pub items: Vec<ProcStatement<'a>>,
+}
+
+#[derive(Debug)]
+pub enum ProcStatement<'a> {
+    IfElse(IfElseBlock),
+    Assign,
+    Match(MatchBlock<'a>),
+}
+
+// TODO: postponed because annoying to implement
+#[derive(Debug)]
+pub struct IfElseBlock {
+}
+
+#[derive(Debug)]
+pub struct MatchBlock<'a> {
+    expr: Expression<'a>,
+    arms: Vec<(&'a str, ProcStatement<'a>)>
 }
 
 #[derive(Debug)]
@@ -180,7 +205,7 @@ fn expression(input: Span) -> IResult<Span, Expression> {
     ))(input)
 }
 
-fn assign_statement(input: Span) -> IResult<Span, Statement> {
+fn assign_statement(input: Span) -> IResult<Span, Assign> {
     context(
         "assignment",
         delimited(
@@ -188,10 +213,10 @@ fn assign_statement(input: Span) -> IResult<Span, Statement> {
             map(
                 separated_pair(ws0(identifier), char('='), ws0(expression)),
                 |(lhs, expr)| {
-                    Statement::Assign(Assign {
+                    Assign {
                         lhs: (*lhs.fragment()),
                         expr,
-                    })
+                    }
                 },
             ),
             ws0(char(';')),
@@ -199,6 +224,47 @@ fn assign_statement(input: Span) -> IResult<Span, Statement> {
     )(input)
 }
 
+/// parse a statement that is valid inside a proc block
+fn proc_statement(input: Span) -> IResult<Span, ProcStatement> {
+    map(
+        nom::character::complete::anychar,
+        |_| {
+            ProcStatement::Match(MatchBlock {
+                expr: Expression::Ident("asdf"),
+                arms: Vec::new(),
+            })
+        }
+    )(input)
+}
+
+fn proc_block(input: Span) -> IResult<Span, ProcBlock> {
+    context(
+        "proc block",
+        map(
+            tuple((
+                ws0(tag("proc")),
+                ws0(delimited(char('('), ws0(identifier), char(')'))),
+                ws0(delimited(char('{'), many0(ws0(proc_statement)), char('}')))
+            )),
+            |(_, net, items)| {
+                ProcBlock {
+                    net,
+                    items,
+                }
+            }
+        )
+    )(input)
+
+}
+
+fn module_item(input: Span) -> IResult<Span, ModuleItem> {
+    alt((
+        map(assign_statement, |assig| ModuleItem::Assign(assig)),
+        map(proc_block, |proc| ModuleItem::Proc(proc)),
+    ))(input)
+}
+
+/// parse a top-level module declaration
 pub fn module(input: Span) -> IResult<Span, Module> {
     context(
         "module",
@@ -209,14 +275,14 @@ pub fn module(input: Span) -> IResult<Span, Module> {
                 ws0(delimited(char('('), ws0(ports_list), char(')'))),
                 ws0(delimited(
                     char('{'),
-                    many1(ws0(assign_statement)),
+                    many1(ws0(module_item)),
                     char('}'),
                 )),
             )),
-            |(_, name, ports, statements)| Module {
+            |(_, name, ports, items)| Module {
                 name: (*name.fragment()),
                 ports,
-                statements,
+                items,
             },
         ),
     )(input)

src/rtlil.rs

@@ -1,5 +1,7 @@
 mod sync;
 
+use sync::Process;
+
 #[derive(Debug, Default)]
 pub struct ILWriter {
     data: String,
@@ -120,6 +122,7 @@ pub struct Module {
     name: String,
     wires: Vec<Wire>,
     cells: Vec<Cell>,
+    processes: Vec<Process>,
     connections: Vec<(SigSpec, SigSpec)>,
     gen_id: i32,
 }
@@ -131,6 +134,7 @@ impl Module {
             wires: Default::default(),
             cells: Default::default(),
             connections: Default::default(),
+            processes: Default::default(),
             gen_id: 0,
         }
     }
@@ -147,6 +151,10 @@ impl Module {
         self.cells.push(cell)
     }
 
+    pub fn add_process(&mut self, proc: Process) {
+        self.processes.push(proc)
+    }
+
     pub fn make_genid(&mut self, stem: &str) -> String {
         let res = format!("${}${}", stem, self.gen_id);
         self.gen_id += 1;
@@ -160,6 +168,7 @@ impl RtlilWrite for Module {
         writer.indent();
         writer.write_iter(&self.wires);
         writer.write_iter(&self.cells);
+        writer.write_iter(&self.processes);
         for conn in &self.connections {
             writer.write_line(&format!("connect {} {}", conn.0, conn.1))
         }

src/rtlil/sync.rs

@@ -1,26 +1,31 @@
 use crate::rtlil::{RtlilWrite, SigSpec};
 
+#[derive(Debug)]
 pub struct Process {
     id: String,
     root_case: CaseRule,
     sync_rules: Vec<SyncRule>,
 }
 
+#[derive(Debug)]
 pub struct CaseRule {
     assign: Vec<(SigSpec, SigSpec)>,
     switches: Vec<SwitchRule>,
 }
 
+#[derive(Debug)]
 pub struct SwitchRule {
     signal: String,
     cases: Vec<CaseRule>,
 }
 
+#[derive(Debug)]
 pub struct SyncRule {
     cond: SyncCond,
     assign: Vec<(SigSpec, SigSpec)>,
 }
 
+#[derive(Debug)]
 pub enum SyncCond {
     Always,
     Posedge(String),