add tools

tools/decode_float.py

@@ -0,0 +1,12 @@
+import struct
+import sys
+
+with open(sys.argv[1], 'r') as f:
+    buf = f.read()
+
+nums = [int(i.strip(), 16) for i in buf.split(',') if i.strip()]
+
+for num in nums:
+    data = struct.pack("<I", num)
+    f, = struct.unpack("<f", data)
+    print(f, 1024 * f)

tools/float_table.py

@@ -0,0 +1,73 @@
+nums = """
+        0 	0.001953125 	0.00390625 	0.005859375 	0.0078125 	0.009765625 	0.01171875 	0.013671875
+ 	0.015625 	0.017578125 	0.01953125 	0.021484375 	0.0234375 	0.025390625 	0.02734375 	0.029296875
+ 	0.03125 	0.03515625 	0.0390625 	0.04296875 	0.046875 	0.05078125 	0.0546875 	0.05859375
+ 	0.0625 	0.0703125 	0.078125 	0.0859375 	0.09375 	0.1015625 	0.109375 	0.1171875
+ 	0.125 	0.140625 	0.15625 	0.171875 	0.1875 	0.203125 	0.21875 	0.234375
+ 	0.25 	0.28125 	0.3125 	0.34375 	0.375 	0.40625 	0.4375 	0.46875
+ 	0.5 	0.5625 	0.625 	0.6875 	0.75 	0.8125 	0.875 	0.9375
+ 	1 	1.125 	1.25 	1.375 	1.5 	1.625 	1.75 	1.875
+ 	2 	2.25 	2.5 	2.75 	3 	3.25 	3.5 	3.75
+ 	4 	4.5 	5 	5.5 	6 	6.5 	7 	7.5
+ 	8 	9 	10 	11 	12 	13 	14 	15
+ 	16 	18 	20 	22 	24 	26 	28 	30
+ 	32 	36 	40 	44 	48 	52 	56 	60
+ 	64 	72 	80 	88 	96 	104 	112 	120
+ 	128 	144 	160 	176 	192 	208 	224 	240
+"""
+
+nums = [float(i) for i in nums.split()]
+
+def parse_043_float(i):
+    get_significand = lambda i: (i >> 0) & 0b111
+    get_exponent = lambda i: (i >> 3) & 0b1111
+    # ieee_754_bias = 2 ** (4 - 1) - 1
+    bias = 7
+
+    exponent = get_exponent(i)
+    significand = get_significand(i)
+
+    base = 8
+    if exponent > 0:
+        significand |= 0b1000
+    else:
+        # denormal
+        if significand == 0:
+            significand = 0b0001
+            base = 16
+        exponent = 1
+
+    value = (significand / base) * 2 ** (exponent - bias)
+    return value
+
+for i, num in enumerate(nums):
+    if num == 0:
+        continue
+    assert num == parse_043_float(i)
+
+assert max(range(128)) == 127
+assert min(range(128)) == 0
+
+def find_nearest(n):
+    value = parse_043_float(0)
+    nearest = 0
+    nearest_diff = abs(value - n)
+
+    for i in range(1, 128):
+        value = parse_043_float(i)
+        diff = abs(value - n)
+        if diff < nearest_diff:
+            nearest = i
+            nearest_diff = diff
+
+    return nearest, parse_043_float(nearest)
+
+if __name__ == "__main__":
+    import sys
+    number = sys.argv[1]
+    if '.' in number:
+        number = float(number)
+        print("nearest", number, *find_nearest(number))
+    else:
+        number = int(number, 10)
+        print(parse_043_float(number))

tools/pascal.py

@@ -0,0 +1,14 @@
+def tri(parents, depth):
+    if depth == 20:
+        return
+
+    new = [1] * (len(parents) + 1)
+    for i in range(1, len(parents)):
+        new[i] = parents[i] + parents[i - 1]
+    if len(new) % 2 == 1:
+        div = sum(new)
+        print(list(reversed([new[i] / div for i in range(len(new) // 2 + 1)])))
+    tri(new, depth + 1)
+
+parents = [1, 2, 1]
+tri(parents, 2)