add range-focussed fp64/32-to-32/16 downconversion tests

these create a number that is *almost* in the target range so that it
will hit the min/max (inf) limit some of the time but not all

diff --git a/src/ieee754/fcvt/test/rangelimited.py b/src/ieee754/fcvt/test/rangelimited.py
index c81e2c37ed2a34a8861af4c17131c3e7d53699ce..eacb35341d5f267e4648a64a8c1e4c284dd9cfd1 100644 (file)
--- a/src/ieee754/fcvt/test/rangelimited.py
+++ b/src/ieee754/fcvt/test/rangelimited.py
@@ -11,6 +11,26 @@ probability of being within the target range or just outside of it
 from random import randint
 from sfpy import Float16, Float32, Float64
 
+def create_ranged_target(fkls, target):
+    """create a targetted floating-point number just within
+       the min/max range, by +/- 0.5%
+    """
+    if randint(0, 1) == 1:
+        target = -target
+    res = fkls(target)
+    fracwid = 1<<50 # biiig number...
+    frac = float(randint(0, fracwid)-fracwid/2) / (fracwid/2) # +/- 0.99999
+    frac = (frac + 500.0) / 500.0 # change to 0.1%
+    res = res * fkls(frac)
+
+    return res.bits
+
+def create_ranged_fp16(fkls):
+    return create_ranged_target(fkls, 65519.0)
+
+def create_ranged_fp32(fkls):
+    return create_ranged_target(fkls, 3.402823466E38)
+
 def create_ranged_float(fkls, mainwid, fracwid):
     """create a floating-point number
 
@@ -32,3 +52,14 @@ def create_int(fkls, intwid):
     """
     return create_ranged_float(fkls, intwid+1, intwid+1)
 
+if __name__ == '__main__':
+    for i in range(10):
+        x = create_ranged_fp16(Float32)
+        print (Float32(x))
+        x = Float32(x)
+        print (Float16(x))
+    for i in range(10):
+        x = create_ranged_fp32(Float64)
+        print (Float64(x))
+        x = Float64(x)
+        print (Float32(x))

diff --git a/src/ieee754/part_bits/__init__.py b/src/ieee754/part_bits/__init__.py
new file mode 100644 (file)
index 0000000..e69de29