wip: deferred OLMC mapping stuff

compiler/src/fitter.rs

@@ -1,5 +1,5 @@
 use crate::pcf::PcfFile;
-use crate::yosys_parser::{GalOLMC, Graph, NamedPort, Net};
+use crate::yosys_parser::{GalOLMC, GalSop, Graph, NamedPort, Net, Node};
 use galette::blueprint::Blueprint;
 use galette::chips::Chip;
 use log::info;
@@ -16,12 +16,63 @@ pub enum MappingError {
     #[error("Could not find the SOP input")]
     MissingSOP,
 
+    #[error("Could not find a sop to fit {0}")]
+    SopTooBig(usize),
+
     #[error("Unknown error")]
     Unknown,
 }
 
 // attempt to map graph into blueprint
 
+/// Acquire the SOP associated with the OLMC. If it's 
+fn get_sop_for_olmc(graph: &Graph, olmc_idx: usize) -> Result<GalSop, MappingError> {
+    let input = graph.get_node_port_conns(olmc_idx, "A");
+    assert_eq!(input.len(), 1, "OLMC input should have one netadjpair");
+    let other_node = input[0].get_other(olmc_idx);
+    let sop = graph
+        .get_node(other_node.0)
+        .ok_or(MappingError::MissingSOP)?;
+    if let Node::Sop(s) = sop {
+        Ok(s.clone())
+    } else {
+        Err(MappingError::MissingSOP)
+    }
+}
+
+fn map_remaining_olcm(graph: &Graph, olmc: usize, unused: Vec<(usize, usize)>) -> Result<usize, MappingError> {
+    // (index, size)
+    let mut chosen_row: Option<(usize, usize)> = None;
+    // FIXME: implement.
+    let sopsize: usize = get_sop_for_olmc(graph, olmc)?.parameters.depth as usize;
+
+    for (olmc_idx, size) in unused {
+        match chosen_row {
+            None => {
+                if size > sopsize {
+                    chosen_row = Some((olmc_idx, size));
+                }
+            }
+            Some(r) => {
+                // we do the comparison (size > SOP Size)
+                if size < r.1 && size > sopsize {
+                    chosen_row = Some((olmc_idx, size));
+                }
+            }
+        }
+    }
+    // at the end, if we have chosen a row, we can swap it in.
+    match chosen_row {
+        Some((row, size)) => {
+            info!("mapping {olmc} size {sopsize} to row {row} with size {size}");
+            Ok(row)
+        },
+        None => {
+            Err(MappingError::SopTooBig(sopsize))
+        }
+    } 
+}
+
 #[derive(Debug, Clone)]
 struct GALMapEntry(GalOLMC, usize); // data and the entry in the graph
 
@@ -35,8 +86,10 @@ pub fn graph_convert(graph: &Graph, pcf: PcfFile, chip: Chip) -> anyhow::Result<
 
     let mut deferrals: Vec<usize> = Vec::new();
 
+    // For all the OLMCs in the graph, we either map it directly since it's constrained to a pin,
+    // or we defer it to later.
     for o in graph.get_olmc_idx() {
-        // find all the nodes named
+        // find all the
         let others: Vec<Net> = graph
             .get_node_port_conns(o, "Y")
             .iter()
@@ -56,6 +109,7 @@ pub fn graph_convert(graph: &Graph, pcf: PcfFile, chip: Chip) -> anyhow::Result<
                 let olmc_row = chip
                     .pin_to_olmc(pin.try_into()?)
                     .ok_or(MappingError::Unknown)?;
+                // TODO: check size of row vs size of SOP
                 info!("Found a real pin to map: Mapping node {o} onto row {olmc_row}");
                 olmcmap[olmc_row] = Some(o);
             }
@@ -72,8 +126,7 @@ pub fn graph_convert(graph: &Graph, pcf: PcfFile, chip: Chip) -> anyhow::Result<
     // to map remainders, we need to find the smallest SOP.
     //
     // Vec<(olmc_index,size)>
-    let unused_rows =
+    let unused_rows = olmcmap
-        olmcmap
         .iter()
         .enumerate()
         .filter_map(|(i, x)| if !x.is_some() { Some(i) } else { None })
@@ -81,28 +134,6 @@ pub fn graph_convert(graph: &Graph, pcf: PcfFile, chip: Chip) -> anyhow::Result<
     // find the smallest row that fits.
 
     let olmc = deferrals[0];
-    let mut chosen_row: Option<(usize, usize)> = None;
-    // FIXME: implement.
-    let sopsize = 0;
-
-    for (olmc_idx, size) in unused_rows {
-
-        match chosen_row {
-            None => {
-                if size > sopsize {
-                    chosen_row = Some((olmc_idx, size));
-                }
-            },
-            Some(r) => {
-                // we do the comparison (size > SOP Size)
-                if size < r.1 && size > sopsize {
-                    chosen_row = Some((olmc_idx, size));
-                }
-            }
-        }
-    }
-
-
 
     Ok(bp)
 }