add layout experiment from

https://bugs.libre-soc.org/show_bug.cgi?id=713#c20

diff --git a/src/ieee754/part/layout_experiment.py b/src/ieee754/part/layout_experiment.py
new file mode 100644 (file)
index 0000000..ec57083
--- /dev/null
+++ b/src/ieee754/part/layout_experiment.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: LGPL-3-or-later
+# See Notices.txt for copyright information
+"""
+Links: https://bugs.libre-soc.org/show_bug.cgi?id=713#c20
+"""
+
+from collections.abc import Mapping
+from pprint import pprint
+# stuff to let it run as stand-alone script
+class Shape:
+    @staticmethod
+    def cast(v):
+        if isinstance(v, Shape):
+            return v
+        assert isinstance(v, int)
+        return Shape(v, False)
+
+    def __init__(self, width=1, signed=False):
+        self.width = width
+        self.signed = signed
+
+    def __repr__(self):
+        if self.signed:
+            return f"signed({self.width})"
+        return f"unsigned({self.width})"
+
+def signed(w):
+    return Shape(w, True)
+
+def unsigned(w):
+    return Shape(w, False)
+
+def PartitionPoints(pp):
+    return pp
+
+# main fn
+def layout(elwid, part_counts, lane_shapes):
+    if not isinstance(lane_shapes, Mapping):
+        lane_shapes = {i: lane_shapes for i in part_counts}
+    lane_shapes = {i: Shape.cast(lane_shapes[i]) for i in part_counts}
+    signed = lane_shapes[0].signed
+    assert all(i.signed == signed for i in lane_shapes.values())
+    part_wid = -min(-lane_shapes[i].width // c for i, c in part_counts.items())
+    part_count = max(part_counts.values())
+    width = part_wid * part_count
+    points = {}
+    for i, c in part_counts.items():
+        def add_p(p):
+            points[p] = points.get(p, False) | (elwid == i)
+        for start in range(0, part_count, c):
+            add_p(start * part_wid) # start of lane
+            add_p(start * part_wid + lane_shapes[i].width) # start of padding
+    points.pop(0, None)
+    points.pop(width, None)
+    return (PartitionPoints(points), Shape(width, signed), lane_shapes,
+        part_wid, part_count)
+
+if __name__ == '__main__':
+    part_counts = {
+        0: 1,
+        1: 1,
+        2: 2,
+        3: 4,
+    }
+
+    for i in range(4):
+        pprint((i, layout(i, part_counts, unsigned(3))))
+
+    for i in range(4):
+        l = {0: signed(5), 1: signed(6), 2: signed(12), 3: signed(24)}
+        pprint((i, layout(i, part_counts, l)))