WIP linking next_pc stages together

crates/cpu/src/config.rs

@@ -35,6 +35,7 @@ pub struct CpuConfig {
     pub out_reg_num_width: usize,
     pub fetch_width: NonZeroUsize,
     pub max_branches_per_fetch: NonZeroUsize,
+    pub max_fetches_in_flight: NonZeroUsize,
     pub log2_fetch_width_in_bytes: u8,
     /// default value for [`UnitConfig::max_in_flight`]
     pub default_unit_max_in_flight: NonZeroUsize,
@@ -55,6 +56,12 @@ impl CpuConfig {
         };
         v
     };
+    pub const DEFAULT_MAX_FETCHES_IN_FLIGHT: NonZeroUsize = {
+        let Some(v) = NonZeroUsize::new(16) else {
+            unreachable!();
+        };
+        v
+    };
     pub const DEFAULT_LOG2_FETCH_WIDTH_IN_BYTES: u8 = 3;
     pub const DEFAULT_UNIT_MAX_IN_FLIGHT: NonZeroUsize = {
         let Some(v) = NonZeroUsize::new(8) else {
@@ -68,6 +75,7 @@ impl CpuConfig {
             out_reg_num_width: Self::DEFAULT_OUT_REG_NUM_WIDTH,
             fetch_width: Self::DEFAULT_FETCH_WIDTH,
             max_branches_per_fetch: Self::DEFAULT_MAX_BRANCHES_PER_FETCH,
+            max_fetches_in_flight: Self::DEFAULT_MAX_FETCHES_IN_FLIGHT,
             log2_fetch_width_in_bytes: Self::DEFAULT_LOG2_FETCH_WIDTH_IN_BYTES,
             default_unit_max_in_flight: Self::DEFAULT_UNIT_MAX_IN_FLIGHT,
             rob_size,
@@ -138,11 +146,20 @@ impl CpuConfig {
 #[hdl(get(|c| c.fetch_width.get()))]
 pub type CpuConfigFetchWidth<C: PhantomConstGet<CpuConfig>> = DynSize;
 
+#[hdl(get(|c| c.fetch_width.get() * 2))]
+pub type TwiceCpuConfigFetchWidth<C: PhantomConstGet<CpuConfig>> = DynSize;
+
 #[hdl(get(|c| c.max_branches_per_fetch.get()))]
 pub type CpuConfigMaxBranchesPerFetch<C: PhantomConstGet<CpuConfig>> = DynSize;
 
+#[hdl(get(|c| c.max_fetches_in_flight.get()))]
+pub type CpuConfigMaxFetchesInFlight<C: PhantomConstGet<CpuConfig>> = DynSize;
+
 #[hdl(get(|c| c.log2_fetch_width_in_bytes.into()))]
 pub type CpuConfigLog2FetchWidthInBytes<C: PhantomConstGet<CpuConfig>> = DynSize;
 
 #[hdl(get(|c| c.fetch_width_in_bytes()))]
 pub type CpuConfigFetchWidthInBytes<C: PhantomConstGet<CpuConfig>> = DynSize;
+
+#[hdl(get(|c| c.rob_size.get()))]
+pub type CpuConfigRobSize<C: PhantomConstGet<CpuConfig>> = DynSize;

crates/cpu/src/next_pc/next_pc.mermaid

@@ -16,10 +16,7 @@ stateDiagram-v2
     br_pred --> post_decode
     post_decode --> next_pc: cancel following
 
-    state "Rename\nDispatch\nExecute" as execute
-    post_decode --> execute
-
-    state "Retire" as retire
-    execute --> retire
-    retire --> [*]
-    retire --> next_pc: cancel following
+    state "Execute/Retire" as execute_retire
+    post_decode --> execute_retire
+    execute_retire --> [*]
+    execute_retire --> next_pc: cancel following

crates/cpu/src/util/array_vec.rs

@@ -165,6 +165,9 @@ impl<T: Type, N: Size> ArrayVec<T, N> {
             Err(value)
         }
     }
+    pub fn truncate_sim(this: &mut SimValue<Self>, len: usize) {
+        *this.len = len.min(*this.len);
+    }
     pub fn mapped_ty<U: Type>(self, new_element_ty: U) -> ArrayVec<U, N> {
         ArrayVec {
             elements: ArrayType[new_element_ty][N::from_usize(self.elements.len())],