From bafebf85951b432d966ae8a22027fa5ca931cccb Mon Sep 17 00:00:00 2001
From: Arnav Sacheti <36746504+arnavsacheti@users.noreply.github.com>
Date: Sun, 19 Oct 2025 21:35:17 -0700
Subject: [PATCH] refactor to use base listener for busdecoder

---
 src/peakrdl_busdecoder/body/__init__.py       |  2 +
 .../body/combinational_body.py                |  4 +-
 src/peakrdl_busdecoder/body/struct_body.py    | 14 ++++-
 src/peakrdl_busdecoder/cpuif/base_cpuif.py    |  9 +---
 src/peakrdl_busdecoder/decoder.py             | 51 ++++++------------
 src/peakrdl_busdecoder/exporter.py            | 21 +++++---
 src/peakrdl_busdecoder/listener.py            | 29 +++++++++++
 src/peakrdl_busdecoder/module_tmpl.sv         | 16 +++---
 src/peakrdl_busdecoder/struct_generator.py    | 52 +++++++++++++++++++
 tests/requirements.txt                        |  3 --
 10 files changed, 136 insertions(+), 65 deletions(-)
 create mode 100644 src/peakrdl_busdecoder/listener.py
 create mode 100644 src/peakrdl_busdecoder/struct_generator.py
 delete mode 100644 tests/requirements.txt

diff --git a/src/peakrdl_busdecoder/body/__init__.py b/src/peakrdl_busdecoder/body/__init__.py
index d8c7574..75289ee 100644
--- a/src/peakrdl_busdecoder/body/__init__.py
+++ b/src/peakrdl_busdecoder/body/__init__.py
@@ -2,11 +2,13 @@ from .body import Body, SupportsStr
 from .combinational_body import CombinationalBody
 from .for_loop_body import ForLoopBody
 from .if_body import IfBody
+from .struct_body import StructBody
 
 __all__ = [
     "Body",
     "CombinationalBody",
     "ForLoopBody",
     "IfBody",
+    "StructBody",
     "SupportsStr",
 ]
diff --git a/src/peakrdl_busdecoder/body/combinational_body.py b/src/peakrdl_busdecoder/body/combinational_body.py
index 75fa6ad..8556882 100644
--- a/src/peakrdl_busdecoder/body/combinational_body.py
+++ b/src/peakrdl_busdecoder/body/combinational_body.py
@@ -6,5 +6,5 @@ from .body import Body
 class CombinationalBody(Body):
     def __str__(self) -> str:
         return f"""always_comb begin
-            {indent(super().__str__(), "    ")}
-        end"""
+{indent(super().__str__(), "    ")}
+end"""
diff --git a/src/peakrdl_busdecoder/body/struct_body.py b/src/peakrdl_busdecoder/body/struct_body.py
index 215d955..a460c4c 100644
--- a/src/peakrdl_busdecoder/body/struct_body.py
+++ b/src/peakrdl_busdecoder/body/struct_body.py
@@ -4,12 +4,22 @@ from .body import Body
 
 
 class StructBody(Body):
-    def __init__(self, name: str, packed: bool = True) -> None:
+    def __init__(self, name: str, typedef: bool = False, packed: bool = False) -> None:
         super().__init__()
         self._name = name
+        self._typedef = typedef
         self._packed = packed
 
+    @property
+    def name(self) -> str:
+        return self._name
+
     def __str__(self) -> str:
-        return f"""typedef struct {"packed " if self._packed else ""} {{
+        if self._typedef:
+            return f"""typedef struct {"packed " if self._packed else ""}{{
+{indent(super().__str__(), "    ")}
+}} {self._name};"""
+
+        return f"""struct {{
 {indent(super().__str__(), "    ")}
 }} {self._name};"""
diff --git a/src/peakrdl_busdecoder/cpuif/base_cpuif.py b/src/peakrdl_busdecoder/cpuif/base_cpuif.py
index 13bf734..33d1161 100644
--- a/src/peakrdl_busdecoder/cpuif/base_cpuif.py
+++ b/src/peakrdl_busdecoder/cpuif/base_cpuif.py
@@ -83,7 +83,7 @@ class BaseCpuif:
         jj_env.filters["is_pow2"] = is_pow2  # type: ignore
         jj_env.filters["roundup_pow2"] = roundup_pow2  # type: ignore
         jj_env.filters["address_slice"] = self.get_address_slice  # type: ignore
-        jj_env.filters["get_path"] = lambda x: get_indexed_path(self.exp.ds.top_node, x, "i") # type: ignore
+        jj_env.filters["get_path"] = lambda x: get_indexed_path(self.exp.ds.top_node, x, "i")  # type: ignore
 
         context = {
             "cpuif": self,
@@ -97,9 +97,4 @@ class BaseCpuif:
         addr = node.raw_absolute_address - self.exp.ds.top_node.raw_absolute_address
         size = node.size
 
-        addr_msb = clog2(addr + size) - 1
-        addr_lsb = clog2(addr)
-
-        if addr_msb == addr_lsb:
-            return f"{cpuif_addr}[{addr_lsb}]"
-        return f"{cpuif_addr}[{addr_msb}:{addr_lsb}]"
+        return f"({cpuif_addr} - 'h{addr:x})[{clog2(size) - 1}:0]"
diff --git a/src/peakrdl_busdecoder/decoder.py b/src/peakrdl_busdecoder/decoder.py
index 38330b9..84e2ae6 100644
--- a/src/peakrdl_busdecoder/decoder.py
+++ b/src/peakrdl_busdecoder/decoder.py
@@ -2,10 +2,11 @@ from collections import deque
 from enum import Enum
 
 from systemrdl.node import AddressableNode
-from systemrdl.walker import RDLListener, RDLSimpleWalker, WalkerAction
+from systemrdl.walker import WalkerAction
 
 from .body import Body, ForLoopBody, IfBody
 from .design_state import DesignState
+from .listener import BusDecoderListener
 from .sv_int import SVInt
 from .utils import get_indexed_path
 
@@ -23,30 +24,17 @@ class DecodeLogicFlavor(Enum):
         return f"cpuif_{self.value}_sel"
 
 
-class AddressDecode:
-    def __init__(self, flavor: DecodeLogicFlavor, ds: DesignState) -> None:
-        self._flavor = flavor
-        self._ds = ds
-
-    def walk(self) -> str:
-        walker = RDLSimpleWalker()
-        dlg = DecodeLogicGenerator(self._flavor, self._ds)
-        walker.walk(self._ds.top_node, dlg, skip_top=True)
-        return str(dlg)
-
-
-class DecodeLogicGenerator(RDLListener):
+class DecodeLogicGenerator(BusDecoderListener):
     def __init__(
         self,
-        flavor: DecodeLogicFlavor,
         ds: DesignState,
+        flavor: DecodeLogicFlavor,
     ) -> None:
-        self._ds = ds
+        super().__init__(ds)
         self._flavor = flavor
 
         self._decode_stack: deque[Body] = deque()  # Tracks decoder body
         self._cond_stack: deque[str] = deque()  # Tracks conditions nested for loops
-        self._array_stride_stack: deque[int] = deque()  # Tracks nested array strids
 
         # Initial Stack Conditions
         self._decode_stack.append(IfBody())
@@ -55,15 +43,19 @@ class DecodeLogicGenerator(RDLListener):
         # Generate address bounds
         addr_width = self._ds.addr_width
         l_bound = SVInt(
-            node.raw_address_offset,
+            node.raw_absolute_address,
             addr_width,
         )
         u_bound = l_bound + SVInt(node.total_size, addr_width)
 
+        array_stack = list(self._array_stride_stack)
+        if node.array_dimensions:
+            array_stack = array_stack[: -len(node.array_dimensions)]
+
         # Handle arrayed components
         l_bound_comp = [str(l_bound)]
         u_bound_comp = [str(u_bound)]
-        for i, stride in enumerate(self._array_stride_stack):
+        for i, stride in enumerate(array_stack):
             l_bound_comp.append(f"({addr_width}'(i{i})*{SVInt(stride, addr_width)})")
             u_bound_comp.append(f"({addr_width}'(i{i})*{SVInt(stride, addr_width)})")
 
@@ -82,30 +74,20 @@ class DecodeLogicGenerator(RDLListener):
         return []
 
     def enter_AddressableComponent(self, node: AddressableNode) -> WalkerAction | None:
+        action = super().enter_AddressableComponent(node)
+
         conditions: list[str] = []
         conditions.extend(self.cpuif_addr_predicate(node))
         conditions.extend(self.cpuif_prot_predicate(node))
 
         condition = " && ".join(f"({c})" for c in conditions)
 
-        if node.array_dimensions:
-            assert node.array_stride is not None, "Array stride should be defined for arrayed components"
-            # Collect strides for each array dimension
-            current_stride = node.array_stride
-            strides: list[int] = []
-            for dim in reversed(node.array_dimensions):
-                strides.append(current_stride)
-                current_stride *= dim
-            strides.reverse()
-            self._array_stride_stack.extend(strides)
-
         # Generate condition string and manage stack
         if isinstance(self._decode_stack[-1], IfBody) and node.array_dimensions:
             # arrayed component with new if-body
             self._cond_stack.append(condition)
             for i, dim in enumerate(
                 node.array_dimensions,
-                start=len(self._array_stride_stack) - len(node.array_dimensions),
             ):
                 fb = ForLoopBody(
                     "int",
@@ -120,10 +102,7 @@ class DecodeLogicGenerator(RDLListener):
             with self._decode_stack[-1].cm(condition) as b:
                 b += f"{self._flavor.cpuif_select}.{get_indexed_path(self._ds.top_node, node)} = 1'b1;"
 
-        # if node.external:
-        #     return WalkerAction.SkipDescendants
-
-        return WalkerAction.Continue
+        return action
 
     def exit_AddressableComponent(self, node: AddressableNode) -> None:
         if not node.array_dimensions:
@@ -148,7 +127,7 @@ class DecodeLogicGenerator(RDLListener):
             else:
                 self._decode_stack[-1] += b
 
-            self._array_stride_stack.pop()
+        super().exit_AddressableComponent(node)
 
     def __str__(self) -> str:
         body = self._decode_stack[-1]
diff --git a/src/peakrdl_busdecoder/exporter.py b/src/peakrdl_busdecoder/exporter.py
index fbeeb14..0e4accb 100644
--- a/src/peakrdl_busdecoder/exporter.py
+++ b/src/peakrdl_busdecoder/exporter.py
@@ -2,17 +2,20 @@ import os
 from datetime import datetime
 from importlib.metadata import version
 from pathlib import Path
-from typing import TYPE_CHECKING, TypedDict
+from typing import TYPE_CHECKING, Any, TypedDict
 
 import jinja2 as jj
 from systemrdl.node import AddrmapNode, RootNode
+from systemrdl.walker import RDLSteerableWalker
 from typing_extensions import Unpack
 
 from .cpuif import BaseCpuif
 from .cpuif.apb4 import APB4Cpuif
-from .decoder import AddressDecode, DecodeLogicFlavor
+from .decoder import DecodeLogicFlavor, DecodeLogicGenerator
 from .design_state import DesignState
 from .identifier_filter import kw_filter as kwf
+from .listener import BusDecoderListener
+from .struct_generator import StructGenerator
 from .sv_int import SVInt
 from .validate_design import DesignValidator
 
@@ -32,7 +35,6 @@ if TYPE_CHECKING:
 
 class BusDecoderExporter:
     cpuif: BaseCpuif
-    address_decode: type[AddressDecode]
     ds: DesignState
 
     def __init__(self, **kwargs: Unpack[ExporterKwargs]) -> None:
@@ -56,6 +58,7 @@ class BusDecoderExporter:
             undefined=jj.StrictUndefined,
         )
         self.jj_env.filters["kwf"] = kwf
+        self.jj_env.filters["walk"] = self.walk
 
     def export(self, node: RootNode | AddrmapNode, output_dir: str, **kwargs: Unpack[ExporterKwargs]) -> None:
         """
@@ -98,7 +101,6 @@ class BusDecoderExporter:
 
         # Construct exporter components
         self.cpuif = cpuif_cls(self)
-        self.address_decode = AddressDecode
 
         # Validate that there are no unsupported constructs
         DesignValidator(self).do_validate()
@@ -108,8 +110,9 @@ class BusDecoderExporter:
             "current_date": datetime.now().strftime("%Y-%m-%d"),
             "version": version("peakrdl-busdecoder"),
             "cpuif": self.cpuif,
-            "address_decode": self.address_decode,
-            "DecodeLogicFlavor": DecodeLogicFlavor,
+            "cpuif_decode": DecodeLogicGenerator,
+            "cpuif_select": StructGenerator,
+            "cpuif_decode_flavor": DecodeLogicFlavor,
             "ds": self.ds,
             "SVInt": SVInt,
         }
@@ -125,3 +128,9 @@ class BusDecoderExporter:
         template = self.jj_env.get_template("module_tmpl.sv")
         stream = template.stream(context)
         stream.dump(module_file_path)
+
+    def walk(self, listener_cls: type[BusDecoderListener], **kwargs: Any) -> BusDecoderListener:
+        walker = RDLSteerableWalker()
+        listener = listener_cls(self.ds, **kwargs)
+        walker.walk(self.ds.top_node, listener, skip_top=True)
+        return str(listener)
diff --git a/src/peakrdl_busdecoder/listener.py b/src/peakrdl_busdecoder/listener.py
new file mode 100644
index 0000000..d459d58
--- /dev/null
+++ b/src/peakrdl_busdecoder/listener.py
@@ -0,0 +1,29 @@
+from collections import deque
+
+from systemrdl.node import AddressableNode, RegNode
+from systemrdl.walker import RDLListener, WalkerAction
+
+from .design_state import DesignState
+
+
+class BusDecoderListener(RDLListener):
+    def __init__(self, ds: DesignState) -> None:
+        self._array_stride_stack: deque[int] = deque()  # Tracks nested array strides
+        self._ds = ds
+
+    def enter_AddressableComponent(self, node: AddressableNode) -> WalkerAction | None:
+        if node.array_dimensions:
+            assert node.array_stride is not None, "Array stride should be defined for arrayed components"
+            self._array_stride_stack.extend(node.array_dimensions)
+
+        if isinstance(node, RegNode):
+            return WalkerAction.SkipDescendants
+        return WalkerAction.Continue
+
+    def exit_AddressableComponent(self, node: AddressableNode) -> None:
+        if node.array_dimensions:
+            for _ in node.array_dimensions:
+                self._array_stride_stack.pop()
+
+    def __str__(self) -> str:
+        return ""
diff --git a/src/peakrdl_busdecoder/module_tmpl.sv b/src/peakrdl_busdecoder/module_tmpl.sv
index 9f6cb7b..bc06565 100644
--- a/src/peakrdl_busdecoder/module_tmpl.sv
+++ b/src/peakrdl_busdecoder/module_tmpl.sv
@@ -32,23 +32,21 @@ module {{ds.module_name}}
     logic [{{cpuif.data_width-1}}:0] cpuif_wr_data;
     logic [{{cpuif.data_width//8-1}}:0] cpuif_wr_byte_en;
 
-    logic cpuif_rd_ack [{{cpuif.addressable_children|length}}];
-    logic cpuif_rd_err [{{cpuif.addressable_children|length}}];
-    logic [{{cpuif.data_width-1}}:0] cpuif_rd_data [{{cpuif.addressable_children|length}}];
+    logic cpuif_rd_ack;
+    logic cpuif_rd_err;
+    logic [{{cpuif.data_width-1}}:0] cpuif_rd_data;
 
     //--------------------------------------------------------------------------
     // Child instance signals
     //--------------------------------------------------------------------------
-    typedef struct packed {
-        
-    } cpuif_sel_t;
+    {{cpuif_select|walk|indent(4)}}
     cpuif_sel_t cpuif_wr_sel;
     cpuif_sel_t cpuif_rd_sel;
 
     //--------------------------------------------------------------------------
     // Slave <-> Internal CPUIF <-> Master
     //--------------------------------------------------------------------------
-    {{-cpuif.get_implementation()|indent}}
+    {{-cpuif.get_implementation()|indent(4)}}
 
     //--------------------------------------------------------------------------
     // Write Address Decoder
@@ -59,7 +57,7 @@ module {{ds.module_name}}
 
         if (cpuif_req && cpuif_wr_en) begin
             // A write request is pending
-            {{address_decode(DecodeLogicFlavor.WRITE, ds).walk()|indent(12)}}
+            {{cpuif_decode|walk(flavor=cpuif_decode_flavor.WRITE)|indent(12)}}
         end else begin
             // No write request, all select signals remain 0
         end
@@ -74,7 +72,7 @@ module {{ds.module_name}}
 
         if (cpuif_req && cpuif_rd_en) begin
             // A read request is pending
-            {{address_decode(DecodeLogicFlavor.READ, ds).walk()|indent(12)}}
+            {{cpuif_decode|walk(flavor=cpuif_decode_flavor.READ)|indent(12)}}
         end else begin
             // No read request, all select signals remain 0
         end
diff --git a/src/peakrdl_busdecoder/struct_generator.py b/src/peakrdl_busdecoder/struct_generator.py
new file mode 100644
index 0000000..d7718c0
--- /dev/null
+++ b/src/peakrdl_busdecoder/struct_generator.py
@@ -0,0 +1,52 @@
+from collections import deque
+
+from systemrdl.node import AddressableNode
+from systemrdl.walker import WalkerAction
+
+from .body import Body, StructBody
+from .design_state import DesignState
+from .identifier_filter import kw_filter as kwf
+from .listener import BusDecoderListener
+
+
+class StructGenerator(BusDecoderListener):
+    def __init__(
+        self,
+        ds: DesignState,
+    ) -> None:
+        super().__init__(ds)
+
+        self._stack: deque[Body] = deque()
+        self._stack.append(StructBody("cpuif_sel_t", True, True))
+
+    def enter_AddressableComponent(self, node: AddressableNode) -> WalkerAction | None:
+        action = super().enter_AddressableComponent(node)
+
+        if node.children():
+            # Push new body onto stack
+            body = StructBody(f"cpuif_sel_{node.inst_name}_t", True, True)
+            self._stack.append(body)
+
+        return action
+
+    def exit_AddressableComponent(self, node: AddressableNode) -> None:
+        type = "logic"
+
+        if node.children():
+            body = self._stack.pop()
+            if body and isinstance(body, StructBody):
+                self._stack.appendleft(body)
+                type = body.name
+
+        name = kwf(node.inst_name)
+
+        if node.array_dimensions:
+            for dim in node.array_dimensions:
+                name += f"[{dim}]"
+
+        self._stack[-1] += f"{type} {name};"
+
+        super().exit_AddressableComponent(node)
+
+    def __str__(self) -> str:
+        return "\n".join(map(str, self._stack))
diff --git a/tests/requirements.txt b/tests/requirements.txt
deleted file mode 100644
index b8b8f50..0000000
--- a/tests/requirements.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-pytest
-systemrdl-compiler
-jinja2