memtest.py

#!/usr/bin/env python

from __future__ import print_function

from prettytable import PrettyTable

MEMORY_UPPER_LIMIT = float(16 * 2<<39)

a = -2
b = a + 1
print('a = %s (%s)' % (a, hex(id(a))))
print('b = %s (%s)' % (b, hex(id(b))))
print('a,b offset = %s' % hex(id(a) - id(b))) # 24 bytes offset???

x = a
y = b
t = t = PrettyTable(['mem_addr', 'int', 'offset', 'direction'])
# while id(x)>=id(y):
for i in range(258):
    x += 1
    y += 1
    offset = id(x) - id(y)
    direction = (
        'high -> low'
        if offset > 0
        else 'low -> high')
    try: t.add_row([
            '%s (%0.16f%%)' % (hex(id(x)), x / MEMORY_UPPER_LIMIT),
            x,
            '%s B' % (offset),
            direction])
    except Exception as error:
        raise error

# do it once more
x += 1
y += 1
offset = id(x) - id(y)
direction = (
    'high -> low'
    if offset > 0
    else 'low -> high')
try: t.add_row([
        '%s (%0.16f%%)' % (hex(id(x)), x / MEMORY_UPPER_LIMIT),
        x,
        '%s B' % (offset),
        direction])
except Exception as error:
    raise error
finally:
    print (t)