Floating-point support in fud (#2318)

Extract floating-point support for `fud` from
#1928

calyx-py/calyx/numeric_types.py

@@ -7,6 +7,7 @@
 from decimal import Decimal, getcontext
 import math
 import logging as log
+import struct
 
 
 class InvalidNumericType(Exception):
@@ -335,3 +336,25 @@ def bitnum_to_fixed(bitnum: Bitnum, int_width: int) -> FixedPoint:
         int_width=int_width,
         is_signed=bitnum.is_signed,
     )
+
+
+@dataclass
+class FloatingPoint(NumericType):
+    """Represents a floating point number."""
+
+    def __init__(self, value: str, width: int, is_signed: bool):
+        super().__init__(value, width, is_signed)
+
+        if self.bit_string_repr is None and self.hex_string_repr is None:
+            # The decimal representation was passed in.
+            packed = struct.pack("!f", float(self.string_repr))
+            unpacked = struct.unpack(">I", packed)[0]
+            self.bit_string_repr = f"{unpacked:0{self.width}b}"
+            self.uint_repr = int(self.bit_string_repr, 2)
+            self.hex_string_repr = np.base_repr(self.uint_repr, 16)
+
+    def to_dec(self, round_place: int):
+        float_value = struct.unpack(
+            "!f", int(self.bit_string_repr, 2).to_bytes(4, byteorder="big")
+        )[0]
+        return round(float_value, round_place)

fud/fud/stages/verilator/json_to_dat.py

@@ -1,6 +1,6 @@
 import simplejson as sjson
 import numpy as np
-from calyx.numeric_types import FixedPoint, Bitnum, InvalidNumericType
+from calyx.numeric_types import FixedPoint, Bitnum, FloatingPoint, InvalidNumericType
 from pathlib import Path
 from fud.errors import Malformed
 import logging as log
@@ -14,7 +14,7 @@ def float_to_fixed(value: float, N: int) -> float:
     return round(value * w) / float(w)
 
 
-def parse_dat(path, args):
+def parse_dat(path, is_bn, args):
     """Parses a number with the given numeric type
     arguments from the array at the given `path`.
     """
@@ -34,12 +34,15 @@ def parse(hex_value: str):
         hex_value = f"0x{hex_value}"
         if "int_width" in args:
             return FixedPoint(hex_value, **args).str_value()
-        else:
+        elif is_bn:
             bn = Bitnum(hex_value, **args)
             if bn.is_undef:
                 return bn.str_value()
             else:
                 return int(bn.str_value())
+        else:
+            fp = FloatingPoint(hex_value, **args)
+            return fp.to_dec(round_place=2)
 
     with path.open("r") as f:
         lines = []
@@ -90,11 +93,14 @@ def provided(x, y):
         )
 
 
-def convert(x, round: bool, is_signed: bool, width: int, int_width=None):
+def convert(x, round: bool, is_signed: bool, width: int, is_bn: bool, int_width=None):
     with_prefix = False
     # If `int_width` is not defined, then this is a `Bitnum`
     if int_width is None:
-        return Bitnum(x, width, is_signed).hex_string(with_prefix)
+        if is_bn:
+            return Bitnum(x, width, is_signed).hex_string(with_prefix)
+        else:
+            return FloatingPoint(x, width, is_signed).hex_string(with_prefix)
 
     try:
         return FixedPoint(x, width, int_width, is_signed).hex_string(with_prefix)
@@ -133,14 +139,16 @@ def convert2dat(output_dir, data, extension, round: bool):
         numeric_type = format["numeric_type"]
         is_signed = format["is_signed"]
 
-        if numeric_type not in {"bitnum", "fixed_point"}:
-            raise InvalidNumericType('Fud only supports "fixed_point" and "bitnum".')
+        if numeric_type not in {"bitnum", "fixed_point", "ieee754_float"}:
+            raise InvalidNumericType(
+                'Fud only supports "fixed_point", "bitnum", and "ieee754_float".'
+            )
 
         is_fp = numeric_type == "fixed_point"
         if is_fp:
             width, int_width = parse_fp_widths(format)
         else:
-            # `Bitnum`s only have a bit width.
+            # `Bitnum`s and `FloatingPoint`s only have a bit width
             width = format["width"]
             int_width = None
 
@@ -154,7 +162,8 @@ def convert2dat(output_dir, data, extension, round: bool):
 
         with path.open("w") as f:
             for v in arr.flatten():
-                f.write(convert(v, round, is_signed, width, int_width) + "\n")
+                is_bn = numeric_type == "bitnum"
+                f.write(convert(v, round, is_signed, width, is_bn, int_width) + "\n")
 
         shape[k]["shape"] = list(arr.shape)
         shape[k]["numeric_type"] = numeric_type
@@ -185,8 +194,9 @@ def convert2json(input_dir, extension):
         # for building the FixedPoint or Bitnum classes.
         args = form.copy()
         del args["shape"]
+        is_bn = args["numeric_type"] == "bitnum"
         del args["numeric_type"]
-        arr = parse_dat(path, args)
+        arr = parse_dat(path, is_bn, args)
         if form["shape"] == [0]:
             raise Malformed(
                 "Data format shape",

runt.toml

@@ -213,6 +213,7 @@ paths = [
   "tests/correctness/ref-cells/*.futil",
   "tests/correctness/sync/*.futil",
   "tests/correctness/static-interface/*.futil",
+  "tests/correctness/ieee754-float/*.futil",
 ]
 cmd = """
 fud exec --from calyx --to jq \

tests/correctness/ieee754-float/parse-and-print.expect

@@ -0,0 +1,9 @@
+{
+  "inp": [
+    15.12
+  ],
+  "out": [
+    15.12,
+    0.56
+  ]
+}

tests/correctness/ieee754-float/parse-and-print.futil

@@ -0,0 +1,38 @@
+import "primitives/core.futil";
+import "primitives/memories/seq.futil";
+import "primitives/float.futil";
+
+component main() -> () {
+    cells {
+        f = std_float_const(0, 32, 0.56);
+        @external inp = seq_mem_d1(32, 1, 1);
+        @external out = seq_mem_d1(32, 2, 2);
+    }
+
+    wires {
+        group set_in {
+            inp.addr0 = 1'd0;
+            inp.content_en = 1'd1;
+            set_in[done] = inp.done;
+        }
+        group write_from_in {
+            out.content_en = 1'd1;
+            out.addr0 = 2'd0;
+            out.write_en = 1'd1;
+            out.write_data = inp.read_data;
+            write_from_in[done] = out.done;
+        }
+        group write_from_const {
+            out.content_en = 1'd1;
+            out.addr0 = 2'd1;
+            out.write_en = 1'd1;
+            out.write_data = f.out;
+            write_from_const[done] = out.done;
+        }
+    }
+    control {
+        set_in;
+        write_from_in;
+        write_from_const;
+    }
+}

tests/correctness/ieee754-float/parse-and-print.futil.data

@@ -0,0 +1,23 @@
+{
+    "inp": {
+        "data": [
+            15.1239
+        ],
+        "format": {
+            "numeric_type": "ieee754_float",
+            "is_signed": false,
+            "width": 32
+        }
+    },
+    "out": {
+        "data": [
+            0.0,
+            0.0
+        ],
+        "format": {
+            "numeric_type": "ieee754_float",
+            "is_signed": false,
+            "width": 32
+        }
+    }
+}