Commit Graph

76 Commits

Author SHA1 Message Date
Jeff Epler c4dafcef4f py/mpz: Avoid undefined behavior at integer overflow in mpz_hash.
Before this, ubsan would detect a problem when executing
hash(006699999999999999999999999999999999999999999999999999999999999999999999)

    ../../py/mpz.c:1539:20: runtime error: left shift of 1067371580458 by
    32 places cannot be represented in type 'mp_int_t' (aka 'long')

When the overflow does occur it now happens as defined by the rules of
unsigned arithmetic.
2018-05-21 12:48:26 +10:00
Damien George f75c7ad1a9 py/mpz: In mpz_clone, remove unused check for NULL dig.
This path for src->deg==NULL is never used because mpz_clone() is always
called with an argument that has a non-zero integer value, and hence has
some digits allocated to it (mpz_clone() is a static function private to
mpz.c all callers of this function first check if the integer value is zero
and if so take a special-case path, bypassing the call to mpz_clone()).

There is some unused and commented-out functions that may actually pass a
zero-valued mpz to mpz_clone(), so some TODOs are added to these function
in case they are needed in the future.
2018-02-25 22:59:19 +11:00
Damien George e784274430 py/mpz: In mpz_as_str_inpl, convert always-false checks to assertions.
There are two checks that are always false so can be converted to (negated)
assertions to save code space and execution time.  They are:

1. The check of the str parameter, which is required to be non-NULL as per
   the original comment that it has enough space in it as calculated by
   mp_int_format_size.  And for all uses of this function str is indeed
   non-NULL.

2. The check of the base parameter, which is already required to be between
   2 and 16 (inclusive) via the assertion in mp_int_format_size.
2017-12-29 14:17:55 +11:00
Damien George 9766fddcdc py/mpz: Simplify handling of borrow and quo adjustment in mpn_div.
The motivation behind this patch is to remove unreachable code in mpn_div.
This unreachable code was added some time ago in
9a21d2e070, when a loop in mpn_div was copied
and adjusted to work when mpz_dig_t was exactly half of the size of
mpz_dbl_dig_t (a common case).  The loop was copied correctly but it wasn't
noticed at the time that the final part of the calculation of num-quo*den
could be optimised, and hence unreachable code was left for a case that
never occurred.

The observation for the optimisation is that the initial value of quo in
mpn_div is either exact or too large (never too small), and therefore the
subtraction of quo*den from num may subtract exactly enough or too much
(but never too little).  Using this observation the part of the algorithm
that handles the borrow value can be simplified, and most importantly this
eliminates the unreachable code.

The new code has been tested with DIG_SIZE=3 and DIG_SIZE=4 by dividing all
possible combinations of non-negative integers with between 0 and 3
(inclusive) mpz digits.
2017-12-29 14:05:48 +11:00
Damien George ae1be76d40 py/mpz: Apply a small code-size optimisation. 2017-12-19 15:45:56 +11:00
Damien George 374eaf5271 py/mpz: Fix pow3 function so it handles the case when 3rd arg is 1.
In this case the result should always be 0, even if 2nd arg is 0.
2017-12-19 15:42:58 +11:00
Alexander Steffen 55f33240f3 all: Use the name MicroPython consistently in comments
There were several different spellings of MicroPython present in comments,
when there should be only one.
2017-07-31 18:35:40 +10:00
Damien George 04552ff71b py: Implement raising a big-int to a negative power.
Before this patch raising a big-int to a negative power would just return
0.  Now it returns a floating-point number with the correct value.
2017-07-25 11:49:22 +10:00
Damien George 4d1fb6107f py/mpz: Make mpz_is_zero() an inline function.
It's more efficient as an inline function, and saves code size.
2017-07-25 11:32:04 +10:00
Damien George f85fd79c6c py/mpz: In mpn_sub, use existing function to remove trailing zeros. 2017-04-25 12:22:04 +10:00
Damien George c7aa86ce6f py/mpz: Strip trailing zeros from mpz value when set from bytes. 2017-04-25 12:06:10 +10:00
Damien George 6ed77bedbd py/mpz: Change type of "base" args from mp_uint_t to unsigned int. 2017-02-16 16:51:16 +11:00
Damien George eb90edb5c0 py/mpz: Remove obsolete declaration of mpz_as_str_size. 2017-02-16 16:51:16 +11:00
Damien George dcdcc43dad py/mpz: Convert mp_uint_t to size_t where appropriate. 2017-02-16 16:51:13 +11:00
Nicko van Someren df0117c8ae py: Added optimised support for 3-argument calls to builtin.pow()
Updated modbuiltin.c to add conditional support for 3-arg calls to
pow() using MICROPY_PY_BUILTINS_POW3 config parameter. Added support in
objint_mpz.c for for optimised implementation.
2017-02-02 22:23:10 +03:00
Paul Sokolovsky 1b42f5251f py/mpz: Implement mpz_set_from_bytes() as a foundation for int.from_bytes(). 2017-01-21 20:07:50 +03:00
Damien George 2d9440e2d1 py/mpz: Fix assertion in mpz_set_from_str which checks value of base. 2016-12-28 12:04:19 +11:00
Damien George e83f140463 py/mpz: Remove unreachable code in mpn_or_neg functions. 2016-12-14 10:39:41 +11:00
Pavol Rusnak 3679ee9b52 py: fix null pointer dereference in mpz.c, fix missing va_end in warning.c 2016-10-31 23:21:15 +03:00
Damien George 8bb7d958f1 py: Factor duplicated function to calculate size of formatted int. 2016-10-11 13:11:32 +11:00
Damien George df3e5d2b2f py/mpz: Use assert to verify mpz does not have a fixed digit buffer. 2016-10-11 13:00:56 +11:00
Damien George 48874942f0 py/mpz: In divmod, replace check for rhs!=0 with assert.
The check for division by zero is made by the caller of this function.
2016-10-11 13:00:01 +11:00
Damien George 460b086333 py/mpz: Fix mpn_div so that it doesn't modify memory of denominator.
Previous to this patch bignum division and modulo would temporarily
modify the RHS argument to the operation (eg x/y would modify y), but on
return the RHS would be restored to its original value.  This is not
allowed because arguments to binary operations are const, and in
particular might live in ROM.  The modification was to normalise the arg
(and then unnormalise before returning), and this patch makes it so the
normalisation is done on the fly and the arg is now accessed as read-only.

This change doesn't increase the order complexity of the operation, and
actually reduces code size.
2016-05-09 17:21:42 +01:00
Damien George 65402ab1ec py/mpz: Do Python style division/modulo within bignum divmod routine.
This patch consolidates the Python logic for division/modulo to one place
within the bignum code.
2016-05-08 22:21:21 +01:00
Damien George dc3faea040 py/mpz: Fix bug with overflowing C-shift in division routine.
When DIG_SIZE=32, a uint32_t is used to store limbs, and no normalisation
is needed because the MSB is already set, then there will be left and
right shifts (in C) by 32 of a 32-bit variable, leading to undefined
behaviour.  This patch fixes this bug.
2016-05-08 21:38:43 +01:00
Damien George ff1a96ce2c py/mpz: Add commented-out mpz_pow3_inpl function, to compute (x**y)%z.
This function computes (x**y)%z in an efficient way.  For large arguments
this operation is otherwise not computable by doing x**y and then %z.

It's currently not used, but is added in case it's useful one day.
2016-02-03 22:30:49 +00:00
Doug Currie 2e2e15cec2 py/mpz: Complete implementation of mpz_{and,or,xor} for negative args.
For these 3 bitwise operations there are now fast functions for
positive-only arguments, and general functions for arbitrary sign
arguments (the fast functions are the existing implementation).

By default the fast functions are not used (to save space) and instead
the general functions are used for all operations.

Enable MICROPY_OPT_MPZ_BITWISE to use the fast functions for positive
arguments.
2016-02-03 22:13:39 +00:00
Damien George 2adf7ec3dd py/mpz: Fix conversion of float to mpz so it works on big endian archs. 2016-01-08 17:56:58 +00:00
Paul Sokolovsky b3be4710aa py/mpz: Normalize (remove leading zeros) xor operation result. 2015-11-22 22:03:18 +02:00
Damien George 2065373f67 py/mpz: Fix bignum anding of large negative with smaller positive int. 2015-10-01 22:35:06 +01:00
Damien George 2f4e8511cd py/mpz: Force rhs of mpz_shl_inpl/mpz_shr_inpl to be unsigned.
Python semantics are that rhs of shift must be non-negative, so there's
no need to handle negative values in the underlying mpz implementation.
2015-10-01 18:01:37 +01:00
Damien George 4c02e54298 py/mpz: Raise NotImplError instead of failing assertion. 2015-10-01 17:57:36 +01:00
Damien George 9472907ae1 py: Fix handling of negative numbers in struct.pack of q/Q. 2015-04-25 23:51:14 +01:00
Damien George 271d18eb08 py: Support conversion of bignum to bytes.
This gets int.to_bytes working for bignum, and also struct.pack with 'q'
and 'Q' args on 32-bit machines.

Addresses issue #1155.
2015-04-25 23:16:39 +01:00
Damien George f66ee4dfd7 py/mpz.c: Fix bug with shl not truncating zero digits correctly. 2015-04-22 23:16:49 +01:00
Damien George 4dea922610 py: Adjust some spaces in code style/format, purely for consistency. 2015-04-09 15:29:54 +00:00
Damien George 848dd0e762 py: Make some mpz functions static and remove unused ones. 2015-03-12 22:48:45 +00:00
Damien George a2e383820d py: Clean up and comment out unused functions in mpz. 2015-03-02 12:58:06 +00:00
Damien George a9dc9b8f6d py: Fix comparison of minus-zero long int. 2015-01-27 17:47:38 +00:00
David Steinberg 8d427b7ab7 py: Fix issue in mpz_set_from_float() when mp_int_t is larger than float 2015-01-24 20:54:28 +00:00
David Steinberg c585ad1020 py: Move mp_float_t related defines to misc.h 2015-01-24 20:54:28 +00:00
Damien George ff8dd3f486 py, unix: Allow to compile with -Wunused-parameter.
See issue #699.
2015-01-20 12:47:20 +00:00
Damien George 963a5a3e82 py, unix: Allow to compile with -Wsign-compare.
See issue #699.
2015-01-16 17:47:07 +00:00
Damien George 58056b0f43 py: Fix handling of "0" mpz in some functions. 2015-01-09 20:58:58 +00:00
Damien George 6fd4b36bc5 py: Raise exception if trying to convert inf/nan to int. 2015-01-02 23:04:09 +00:00
David Steinberg 6e0b6d02db py: Fix float to int conversion for large exponents. 2015-01-02 22:31:41 +00:00
Damien George 51dfcb4bb7 py: Move to guarded includes, everywhere in py/ core.
Addresses issue #1022.
2015-01-01 20:32:09 +00:00
Damien George e0ac194f4f py: Fix rshift and not of zero/one edge cases in mpz.
Addresses issue #1027.
2014-12-31 19:35:01 +00:00
stijn 0e557facb9 mpz: Fix 64bit msvc build
msvc does not treat 1L a 64bit integer hence all occurences of shifting it left or right
result in undefined behaviour since the maximum allowed shift count for 32bit ints is 31.
Forcing the correct type explicitely, stored in MPZ_LONG_1, solves this.
2014-10-30 23:00:24 +00:00
Damien George 42f3de924b py: Convert [u]int to mp_[u]int_t where appropriate.
Addressing issue #50.
2014-10-03 17:44:14 +00:00