From: Jacob Lifshay <programmerjake@gmail.com>
Date: Mon, 4 Jul 2022 10:42:27 +0000 (-0700)
Subject: add FPFormat.get_exponent_value to get an unbiased exponent corrected for subnormals
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=da903f9bc46de51cae1f4a8fd9e9ea2d83bd572a;p=ieee754fpu.git

add FPFormat.get_exponent_value to get an unbiased exponent corrected for subnormals
---

diff --git a/src/ieee754/fpcommon/fpbase.py b/src/ieee754/fpcommon/fpbase.py
index 9f537e02..84768edc 100644
--- a/src/ieee754/fpcommon/fpbase.py
+++ b/src/ieee754/fpcommon/fpbase.py
@@ -320,6 +320,17 @@ class FPFormat:
             x |= Const(0, signed(1))
         return x - self.exponent_bias
 
+    def get_exponent_value(self, x):
+        """ returns the exponent of its input number, x, adjusted for the
+        mathematically correct subnormal exponent.
+        """
+        x = self.get_exponent_field(x)
+        if isinstance(x, Value) and not x.shape().signed:
+            # convert x to signed without changing its value,
+            # since exponents can be negative
+            x |= Const(0, signed(1))
+        return x + (x == self.exponent_denormal_zero) - self.exponent_bias
+
     def get_mantissa_field(self, x):
         """ returns the mantissa of its input number, x
         """