Add test case for NaN and -0 handling to fpmax

[ieee754fpu.git] / src / ieee754 / fpmax / test / test_fpmax_pipe.py

diff --git a/src/ieee754/fpmax/test/test_fpmax_pipe.py b/src/ieee754/fpmax/test/test_fpmax_pipe.py
index 65823f3f5daf4ed8c3c3936af4f8ba1b565c667e..a2f2174ea123bdca002e3751e37712a2736e9725 100644 (file)
--- a/src/ieee754/fpmax/test/test_fpmax_pipe.py
+++ b/src/ieee754/fpmax/test/test_fpmax_pipe.py
@@ -3,19 +3,41 @@
 
 from ieee754.fpmax.pipeline import (FPMAXMuxInOut)
 from ieee754.fpcommon.test.fpmux import runfp
+from ieee754.fpcommon.test.case_gen import run_pipe_fp
+from ieee754.fpcommon.test import unit_test_single
 
 from sfpy import Float16, Float32, Float64
 import math
 
+
 def fpmax_f32_max(a, b):
-    
+    # Apparently, sfpy doesn't include a min or max function. Python's
+    # min/max work, however python min/max are not IEEE754 Compliant
+    # (namely, they don't behave correctly with NaNs
+    # IEEE754 defines max(num, NaN) and max(NaN, num) as both
+    # returning num (and the same for min)
     if math.isnan(a) or math.isnan(b):
         if math.isnan(a) and math.isnan(b):
             return Float32(float('nan'))
         else:
             return b if math.isnan(a) else a
-                    
-    if a > b:
+    if a.bits & (1<<31) != b.bits & (1<<31):
+        return b if a.bits & (1<<31) else a
+    elif a > b:
+        return a
+    else:
+        return b
+
+
+def fpmax_f32_min(a, b):
+    if math.isnan(a) or math.isnan(b):
+        if math.isnan(a) and math.isnan(b):
+            return Float32(float('nan'))
+        else:
+            return b if math.isnan(a) else a
+    if a.bits & (1<<31) != b.bits & (1<<31):
+        return a if a.bits & (1<<31) else b
+    elif a < b:
         return a
     else:
         return b
@@ -27,6 +49,31 @@ def test_fpmax_f32_max():
           n_vals=100, opcode=0x0)
 
 
+def test_fpmax_f32_min():
+    dut = FPMAXMuxInOut(32, 4)
+    runfp(dut, 32, "test_fpmax_f32_min", Float32, fpmax_f32_min,
+          n_vals=100, opcode=0x1)
+
+def nan_testcases():
+    nan = Float32(float('nan')).bits
+    yield nan, Float32(1.0).bits
+    yield Float32(1.0).bits, nan
+    yield nan, nan
+    yield Float32(0.0).bits, Float32(-0.0).bits
+    yield Float32(-0.0).bits, Float32(0.0).bits
+
+def test_fpmax_f32_nans():
+    dut = FPMAXMuxInOut(32, 4)
+    run_pipe_fp(dut, 32, "test_fpmax_f32_max_nans", unit_test_single,
+                Float32, nan_testcases, fpmax_f32_max, 5,
+                opcode=0b0)
+    run_pipe_fp(dut, 32, "test_fpmax_f32_min_nans", unit_test_single,
+                Float32, nan_testcases, fpmax_f32_min, 5,
+                opcode=0b1)
+
+
 if __name__ == '__main__':
+    test_fpmax_f32_nans()
     for i in range(50):
         test_fpmax_f32_max()
+        test_fpmax_f32_min()