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.
The type is an unsigned 8-bit value, since bytes objects are exactly
that. And it's also sensible for unicode strings to return unsigned
values when accessed in a byte-wise manner (CPython does not allow this).
All tests in basics/ directory can now run and pass using 64-bit unix
port with only a 16k heap (./run-tests --heapsize 16k). Tests in this
directory should remain small so they can be used for ports with a
small heap.
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.
Eg: '{:{}}'.format(123, '>20')
@pohmelie was the original author of this patch, but @dpgeorge made
significant changes to reduce code size and improve efficiency.
Antonin ENFRUN
Paul Sokolovsky
Damien George
Doug Currie
pohmelie