reduce the number of wires to have one per form/field pair instead of one per insn/field pair

crates/cpu/src/decoder/simple_power_isa.rs

@@ -20,14 +20,9 @@ use crate::{
         array_vec::{ArrayVec, Length},
     },
 };
-use fayalite::{
-    int::{BoolOrIntType, UIntInRange},
-    module::wire_with_loc,
-    prelude::*,
-    ty::StaticType,
-};
+use fayalite::{int::UIntInRange, module::wire_with_loc, prelude::*, ty::StaticType};
 use std::{
-    collections::{BTreeMap, btree_map::Entry},
+    collections::{BTreeMap, HashMap, hash_map::Entry},
     ops::RangeInclusive,
 };
 
@@ -136,7 +131,7 @@ const VSX_MNEMONICS: &[&str] = &[
 ];
 
 #[derive(Debug)]
-struct DecodeState {
+struct DecodeState<'a> {
     mnemonic: &'static str,
     arguments: Option<&'static str>,
     conditions: Option<&'static str>,
@@ -147,6 +142,7 @@ struct DecodeState {
     first_input: Expr<UInt<32>>,
     second_input: Expr<HdlOption<UInt<32>>>,
     second_input_used: Expr<Bool>,
+    field_wires: &'a mut HashMap<String, HashMap<Expr<UInt>, Expr<UInt>>>,
 }
 
 trait FieldSet {
@@ -320,7 +316,7 @@ fn cr_bit_flag_index(
     (MOpRegNum::power_isa_cr_reg(field_num), flag_index)
 }
 
-impl DecodeState {
+impl DecodeState<'_> {
     fn form(&self) -> &'static str {
         let mut title_words = self
             .header
@@ -399,6 +395,26 @@ impl DecodeState {
             (var.trim(), value.trim())
         })
     }
+    fn get_field_wire(&mut self, value: Expr<UInt>, name: &str) -> Expr<UInt> {
+        let form = self.form();
+        let width = value.ty().width();
+        let wire_name =
+            format!("{form}_{name}_{width}").replace(|c: char| !c.is_ascii_alphanumeric(), "_");
+        match self
+            .field_wires
+            .entry(wire_name.clone())
+            .or_default()
+            .entry(value)
+        {
+            Entry::Vacant(entry) => {
+                let wire = wire_with_loc(&wire_name, SourceLocation::caller(), value.ty());
+                connect(wire, value);
+                entry.insert(wire);
+                wire
+            }
+            Entry::Occupied(entry) => *entry.get(),
+        }
+    }
     #[hdl]
     fn decode_word(
         &mut self,
@@ -478,27 +494,19 @@ impl DecodeState {
                 };
                 field_pieces.filled_pieces.push(field);
                 if field_pieces.filled_pieces.len() == field_pieces.piece_count {
-                    let wire = wire_with_loc(
-                        &format!("{}_{name}", self.mnemonic)
-                            .replace(|c: char| !c.is_ascii_alphanumeric(), "_"),
-                        SourceLocation::caller(),
-                        UInt[field_pieces
-                            .filled_pieces
-                            .iter()
-                            .map(|v| v.ty().width())
-                            .sum::<usize>()],
-                    );
+                    let filled_pieces = std::mem::take(&mut field_pieces.filled_pieces);
                     // filled_pieces are in lsb to msb order
-                    let mut filled_pieces = field_pieces.filled_pieces.drain(..);
+                    let mut filled_pieces = filled_pieces.into_iter();
                     let Some(mut value) = filled_pieces.next() else {
                         unreachable!();
                     };
-                    let mut shift = value.ty().width();
+                    let mut value_width = value.ty().width();
                     for next_value in filled_pieces {
-                        value = value | (next_value << shift);
-                        shift += next_value.ty().width();
+                        value = value | (next_value << value_width);
+                        value_width += next_value.ty().width();
                     }
-                    connect(wire, value);
+                    value = value.cast_to(UInt[value_width]);
+                    let wire = self.get_field_wire(value, name);
                     fields.insert(name, wire);
                 }
             } else {
@@ -523,8 +531,8 @@ impl DecodeState {
         let mut f = Some(f);
         #[hdl]
         #[track_caller]
-        fn run<FS: FieldSet, F: FnOnce(&mut DecodeState, FS)>(
-            this: &mut DecodeState,
+        fn run<'a, FS: FieldSet, F: FnOnce(&mut DecodeState<'a>, FS)>(
+            this: &mut DecodeState<'a>,
             matches: Expr<Bool>,
             fields: &mut BTreeMap<&str, Expr<UInt>>,
             f: &mut Option<F>,
@@ -2082,23 +2090,25 @@ impl DecodeState {
     }
 }
 
-type DecodeFn = fn(&mut DecodeState);
+type DecodeFn = fn(&mut DecodeState<'_>);
 
 const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
-    (&["b", "ba", "bl", "bla"], DecodeState::decode_b_ba_bl_bla),
+    (&["b", "ba", "bl", "bla"], |state| {
+        DecodeState::decode_b_ba_bl_bla(state)
+    }),
     (
         &[
             "bc", "bca", "bcl", "bcla", "bclr", "bclrl", "bcctr", "bcctrl", "bctar", "bctarl",
         ],
-        DecodeState::decode_bc_bclr_bcctr_bctar,
+        |state| DecodeState::decode_bc_bclr_bcctr_bctar(state),
     ),
     (
         &[
             "crand", "crnand", "cror", "crxor", "crnor", "creqv", "crandc", "crorc",
         ],
-        DecodeState::decode_crand_crnand_cror_crxor_crnor_creqv_crandc_crorc,
+        |state| DecodeState::decode_crand_crnand_cror_crxor_crnor_creqv_crandc_crorc(state),
     ),
-    (&["mcrf"], DecodeState::decode_mcrf),
+    (&["mcrf"], |state| DecodeState::decode_mcrf(state)),
     (&["sc", "scv"], |_state| {
         // TODO
     }),
@@ -2108,14 +2118,14 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
             "plha", "lhax", "lhau", "lhaux", "lwz", "plwz", "lwzx", "lwzu", "lwzux", "lwa", "plwa",
             "lwax", "lwaux", "ld", "pld", "ldx", "ldu", "ldux",
         ],
-        DecodeState::decode_load_8_16_32_64_bit,
+        |state| DecodeState::decode_load_8_16_32_64_bit(state),
     ),
     (
         &[
             "stb", "pstb", "stbx", "stbu", "stbux", "sth", "psth", "sthx", "sthu", "sthux", "stw",
             "pstw", "stwx", "stwu", "stwux", "std", "pstd", "stdx", "stdu", "stdux",
         ],
-        DecodeState::decode_store_8_16_32_64_bit,
+        |state| DecodeState::decode_store_8_16_32_64_bit(state),
     ),
     (&["lq", "plq", "stq", "pstq"], |_state| {
         // TODO
@@ -2132,43 +2142,46 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
     (&["lswi", "lswx", "stswi", "stswx"], |_state| {
         // load/store string are intentionally not implemented
     }),
-    (&["addi", "paddi"], DecodeState::decode_addi_paddi),
-    (&["addis"], DecodeState::decode_addis),
-    (&["addpcis"], DecodeState::decode_addpcis),
-    (&["add", "add.", "addo", "addo."], DecodeState::decode_add),
-    (&["addic", "addic."], DecodeState::decode_addic),
-    (
-        &["subf", "subf.", "subfo", "subfo."],
-        DecodeState::decode_subf_subfc,
-    ),
-    (&["subfic"], DecodeState::decode_subfic),
-    (
-        &["addc", "addc.", "addco", "addco."],
-        DecodeState::decode_addc,
-    ),
-    (
-        &["subfc", "subfc.", "subfco", "subfco."],
-        DecodeState::decode_subf_subfc,
-    ),
-    (
-        &["adde", "adde.", "addeo", "addeo."],
-        DecodeState::decode_adde,
-    ),
-    (
-        &["subfe", "subfe.", "subfeo", "subfeo."],
-        DecodeState::decode_subfe,
-    ),
+    (&["addi", "paddi"], |state| {
+        DecodeState::decode_addi_paddi(state)
+    }),
+    (&["addis"], |state| DecodeState::decode_addis(state)),
+    (&["addpcis"], |state| DecodeState::decode_addpcis(state)),
+    (&["add", "add.", "addo", "addo."], |state| {
+        DecodeState::decode_add(state)
+    }),
+    (&["addic", "addic."], |state| {
+        DecodeState::decode_addic(state)
+    }),
+    (&["subf", "subf.", "subfo", "subfo."], |state| {
+        DecodeState::decode_subf_subfc(state)
+    }),
+    (&["subfic"], |state| DecodeState::decode_subfic(state)),
+    (&["addc", "addc.", "addco", "addco."], |state| {
+        DecodeState::decode_addc(state)
+    }),
+    (&["subfc", "subfc.", "subfco", "subfco."], |state| {
+        DecodeState::decode_subf_subfc(state)
+    }),
+    (&["adde", "adde.", "addeo", "addeo."], |state| {
+        DecodeState::decode_adde(state)
+    }),
+    (&["subfe", "subfe.", "subfeo", "subfeo."], |state| {
+        DecodeState::decode_subfe(state)
+    }),
     (
         &[
             "addme", "addme.", "addmeo", "addmeo.", "addze", "addze.", "addzeo", "addzeo.",
             "subfme", "subfme.", "subfmeo", "subfmeo.", "subfze", "subfze.", "subfzeo", "subfzeo.",
         ],
-        DecodeState::decode_addme_subfme_addze_subfze,
+        |state| DecodeState::decode_addme_subfme_addze_subfze(state),
     ),
     (&["addex"], |_state| {
         // TODO
     }),
-    (&["neg", "neg.", "nego", "nego."], DecodeState::decode_neg),
+    (&["neg", "neg.", "nego", "nego."], |state| {
+        DecodeState::decode_neg(state)
+    }),
     (
         &[
             "mulli", "mullw", "mullw.", "mullwo", "mullwo.", "mulhw", "mulhw.", "mulhwu", "mulhwu.",
@@ -2209,12 +2222,12 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
             // TODO
         },
     ),
-    (&["cmpi"], DecodeState::decode_cmpi),
-    (&["cmp"], DecodeState::decode_cmp),
-    (&["cmpli"], DecodeState::decode_cmpli),
-    (&["cmpl"], DecodeState::decode_cmpl),
-    (&["cmprb"], DecodeState::decode_cmprb),
-    (&["cmpeqb"], DecodeState::decode_cmpeqb),
+    (&["cmpi"], |state| DecodeState::decode_cmpi(state)),
+    (&["cmp"], |state| DecodeState::decode_cmp(state)),
+    (&["cmpli"], |state| DecodeState::decode_cmpli(state)),
+    (&["cmpl"], |state| DecodeState::decode_cmpl(state)),
+    (&["cmprb"], |state| DecodeState::decode_cmprb(state)),
+    (&["cmpeqb"], |state| DecodeState::decode_cmpeqb(state)),
     (&["twi", "tw", "tdi", "td"], |_state| {
         // TODO
     }),
@@ -2223,18 +2236,18 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
     }),
     (
         &["andi.", "andis.", "ori", "oris", "xori", "xoris"],
-        DecodeState::decode_andis_oris_xoris,
+        |state| DecodeState::decode_andis_oris_xoris(state),
     ),
     (
         &[
             "and", "and.", "xor", "xor.", "nand", "nand.", "or", "or.", "orc", "orc.", "nor",
             "nor.", "eqv", "eqv.", "andc", "andc.",
         ],
-        DecodeState::decode_and_xor_nand_or_orc_nor_eqv_andc,
+        |state| DecodeState::decode_and_xor_nand_or_orc_nor_eqv_andc(state),
     ),
     (
         &["extsb", "extsb.", "extsh", "extsh.", "extsw", "extsw."],
-        DecodeState::decode_extsb_extsh_extsw,
+        |state| DecodeState::decode_extsb_extsh_extsw(state),
     ),
     (&["cmpb"], |_state| {
         // TODO
@@ -2264,7 +2277,7 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
             "slw", "slw.", "srw", "srw.", "srawi", "srawi.", "sraw", "sraw.", "sld", "sld.",
             "sradi", "sradi.", "srd", "srd.", "srad", "srad.",
         ],
-        DecodeState::decode_shift,
+        |state| DecodeState::decode_shift(state),
     ),
     (&["extswsli", "extswsli."], |_state| {
         // TODO
@@ -2292,7 +2305,7 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
             // TODO
         },
     ),
-    (&["mcrxrx"], DecodeState::decode_mcrxrx),
+    (&["mcrxrx"], |state| DecodeState::decode_mcrxrx(state)),
     (
         &[
             "mtocrf", "mtcrf", "mfocrf", "mfcr", "setb", "setbc", "setbcr", "setnbc", "setnbcr",
@@ -2301,7 +2314,7 @@ const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
             // TODO
         },
     ),
-    (&["pnop"], DecodeState::decode_pnop),
+    (&["pnop"], |state| DecodeState::decode_pnop(state)),
     (FP_MNEMONICS, |_state| {
         // TODO(FP)
     }),
@@ -2395,6 +2408,7 @@ pub fn decode_one_insn() {
             assert!(!duplicate, "duplicate mnemonic in DECODE_FNS: {mnemonic:?}");
         }
     }
+    let mut field_wires = Default::default();
     for insn in Instructions::get().instructions() {
         for header in insn.header() {
             for mnemonic_line in header.mnemonics().lines() {
@@ -2438,6 +2452,7 @@ pub fn decode_one_insn() {
                     first_input,
                     second_input,
                     second_input_used,
+                    field_wires: &mut field_wires,
                 });
             }
         }