From 031fafb3112f83dea18443f0c0b9e43418789e61 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 10 Feb 2020 14:40:20 +0000
Subject: [PATCH] bug #113, add range-limited random numbers more likely to get
 within the target range of the integer to be converted to

---
 src/ieee754/fcvt/test/rangelimited.py         | 34 ++++++++++++++
 src/ieee754/fcvt/test/test_fcvt_f2int_pipe.py | 45 +++++++++++++++----
 2 files changed, 71 insertions(+), 8 deletions(-)
 create mode 100644 src/ieee754/fcvt/test/rangelimited.py

diff --git a/src/ieee754/fcvt/test/rangelimited.py b/src/ieee754/fcvt/test/rangelimited.py
new file mode 100644
index 00000000..c81e2c37
--- /dev/null
+++ b/src/ieee754/fcvt/test/rangelimited.py
@@ -0,0 +1,34 @@
+"""creates fp numbers that are range-limited
+
+to properly test FPtoFP (higher to lower) and FPtoINT (higher to lower)
+it's no good having FP numbers that, statistically 99.99% of the time,
+are going to be converted to INF (max of the int or float).
+
+therefore, numbers need to be *specifically* generated that have a high
+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_float(fkls, mainwid, fracwid):
+    """create a floating-point number
+
+    range: +/- twice the bit-range
+    fractional part: to ensure that there's plenty to play with
+    """
+    mainwid = 1<<mainwid
+    fracwid = 1<<fracwid
+    v = float(randint(0, mainwid) - mainwid/2)
+    frac = float(randint(0, fracwid)-fracwid/2) / (fracwid/2)
+
+    # deliberately do them separate in case of overflow.
+    # if done as "fkls(v + frac)" it's not the same
+    x = fkls(v) + fkls(frac)
+    return x.bits
+
+def create_int(fkls, intwid):
+    """create a floating-point number to fit into an integer
+    """
+    return create_ranged_float(fkls, intwid+1, intwid+1)
+
diff --git a/src/ieee754/fcvt/test/test_fcvt_f2int_pipe.py b/src/ieee754/fcvt/test/test_fcvt_f2int_pipe.py
index 4e01d8c2..affd63d4 100644
--- a/src/ieee754/fcvt/test/test_fcvt_f2int_pipe.py
+++ b/src/ieee754/fcvt/test/test_fcvt_f2int_pipe.py
@@ -2,7 +2,8 @@
 """
 
 from ieee754.fcvt.pipeline import (FPCVTF2IntMuxInOut,)
-from ieee754.fpcommon.test.fpmux import runfp
+from ieee754.fpcommon.test.fpmux import (runfp, create_random)
+from ieee754.fcvt.test.rangelimited import create_int
 
 import sfpy
 from sfpy import Float64, Float32, Float16
@@ -92,22 +93,34 @@ def test_int_pipe_i32_f32():
 
 def test_int_pipe_f64_i64():
     dut = FPCVTF2IntMuxInOut(64, 64, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float64, 64))
+    vals += create_random(dut.num_rows, 64, True, 10)
     runfp(dut, 64, "test_fcvt_f2int_pipe_f64_i64", Float64, fcvt_f64_i64,
-                True, n_vals=100, opcode=0x1)
+                True, vals=vals, opcode=0x1)
 
 def test_int_pipe_f64_i32():
     # XXX TODO: reduce range of FP num to actually fit (almost) into I32
     # http://bugs.libre-riscv.org/show_bug.cgi?id=113
     dut = FPCVTF2IntMuxInOut(64, 32, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float64, 32))
+    vals += create_random(dut.num_rows, 32, True, 10)
     runfp(dut, 64, "test_fcvt_f2int_pipe_f64_i32", Float64, fcvt_f64_i32,
-                    True, n_vals=100, opcode=0x1)
+                    True, vals=vals, opcode=0x1)
 
 def test_int_pipe_f64_i16():
     # XXX TODO: reduce range of FP num to actually fit (almost) into I16
     # http://bugs.libre-riscv.org/show_bug.cgi?id=113
     dut = FPCVTF2IntMuxInOut(64, 16, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float64, 16))
+    vals += create_random(dut.num_rows, 16, True, 10)
     runfp(dut, 64, "test_fcvt_f2int_pipe_f64_i16", Float64, fcvt_f64_i16,
-                    True, n_vals=100, opcode=0x1)
+                    True, vals=vals, opcode=0x1)
 
 def test_int_pipe_f32_i32():
     dut = FPCVTF2IntMuxInOut(32, 32, 4, op_wid=1)
@@ -137,8 +150,12 @@ def test_int_pipe_ui16_f64():
 
 def test_int_pipe_f32_ui32():
     dut = FPCVTF2IntMuxInOut(32, 32, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float32, 32))
+    vals += create_random(dut.num_rows, 32, True, 10)
     runfp(dut, 32, "test_fcvt_f2int_pipe_f32_ui32", Float32, fcvt_f32_ui32,
-                    True, n_vals=100)
+                    True, vals=vals)
 
 def test_int_pipe_ui32_f64():
     dut = FPCVTIntMuxInOut(32, 64, 4, op_wid=1)
@@ -171,18 +188,30 @@ def test_int_pipe_ui32_f16():
 
 def test_int_pipe_f64_ui64():
     dut = FPCVTF2IntMuxInOut(64, 64, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float64, 64))
+    vals += create_random(dut.num_rows, 64, True, 10)
     runfp(dut, 64, "test_fcvt_f2int_pipe_f64_ui64", Float64, fcvt_f64_ui64,
-                    True, n_vals=100)
+                    True, vals=vals)
 
 def test_int_pipe_f64_ui32():
     dut = FPCVTF2IntMuxInOut(64, 32, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float64, 32))
+    vals += create_random(dut.num_rows, 32, True, 10)
     runfp(dut, 64, "test_fcvt_f2int_pipe_f64_ui32", Float64, fcvt_f64_ui32,
-                    True, n_vals=100)
+                    True, vals=vals)
 
 def test_int_pipe_f64_ui16():
     dut = FPCVTF2IntMuxInOut(64, 16, 4, op_wid=1)
+    vals = []
+    for i in range(100):
+        vals.append(create_int(Float64, 16))
+    vals += create_random(dut.num_rows, 16, True, 10)
     runfp(dut, 64, "test_fcvt_f2int_pipe_f64_ui16", Float64, fcvt_f64_ui16,
-                    True, n_vals=100)
+                    True, vals=vals)
 
 if __name__ == '__main__':
     for i in range(200):
-- 
2.30.2