circuitpython/tests/basics/int_small.py
Damien George 12c66be2b8 tests: Add some tests to improve coverage.
Used gcov to find some parts of vm.c, runtime.c, obj.c that were not
covered by any tests.  Still need to use gcov more thoroughly.
2015-01-29 00:44:11 +00:00

74 lines
1.4 KiB
Python

# This tests small int range for 32-bit machine
# Small ints are variable-length encoded in MicroPython, so first
# test that encoding works as expected.
print(0)
print(1)
print(-1)
# Value is split in 7-bit "subwords", and taking into account that all
# ints in Python are signed, there're 6 bits of magnitude. So, around 2^6
# there's "turning point"
print(63)
print(64)
print(65)
print(-63)
print(-64)
print(-65)
# Maximum values of small ints on 32-bit platform
print(1073741823)
# Per python semantics, lexical integer is without a sign (i.e. positive)
# and '-' is unary minus operation applied to it. That's why -1073741824
# (min two-complement's negative value) is not allowed.
print(-1073741823)
# Operations tests
a = 0x3fffff
print(a)
a *= 0x10
print(a)
a *= 0x10
print(a)
a += 0xff
print(a)
# This would overflow
#a += 1
a = -0x3fffff
print(a)
a *= 0x10
print(a)
a *= 0x10
print(a)
a -= 0xff
print(a)
# This still doesn't overflow
a -= 1
print(a)
# This would overflow
#a -= 1
# negative shifts are not allowed
try:
a << -1
except ValueError:
print("ValueError")
try:
a >> -1
except ValueError:
print("ValueError")
# Shifts to big amounts are undefined behavior in C and is CPU-specific
# These are compile-time constexprs
print(1 >> 32)
print(1 >> 64)
print(1 >> 128)
# These are runtime calcs
a = 1
print(a >> 32)
print(a >> 64)
print(a >> 128)