0a59938574
For certain operands to mpn_div, the existing code path for `DIG_SIZE == MPZ_DBL_DIG_SIZE / 2` had a bug in it where borrow could still overflow in the `(x >= *n || *n - x <= borrow)` branch, ie `borrow + x - (mpz_dbl_dig_t)*n` overflows the borrow variable. In such cases the subsequent right-shift of borrow would not bring in the overflow bit, leading to an error in the result. An example division that had overflow when MPZ_DIG_SIZE = 16 is `(2 ** 48 - 1) ** 2 // (2 ** 48 - 1)`. This is fixed in this commit by simplifying the code and handling the low digits of borrow first, and then the upper bits (to shift down) separately. There is no longer a distinction between `DIG_SIZE < MPZ_DBL_DIG_SIZE / 2` and `DIG_SIZE == MPZ_DBL_DIG_SIZE / 2`. This commit also simplifies the second part of the calculation so that borrow does not need to be negated (instead the code just works knowing that borrow is negative and using + instead of - in calculations involving borrow). Fixes #6777. Signed-off-by: Damien George <damien@micropython.org> |
||
|---|---|---|
| .. | ||
| basics | ||
| cmdline | ||
| cpydiff | ||
| esp32 | ||
| extmod | ||
| feature_check | ||
| float | ||
| import | ||
| inlineasm | ||
| internal_bench | ||
| io | ||
| jni | ||
| micropython | ||
| misc | ||
| multi_bluetooth | ||
| multi_net | ||
| net_hosted | ||
| net_inet | ||
| perf_bench | ||
| pyb | ||
| pybnative | ||
| qemu-arm | ||
| stress | ||
| thread | ||
| unicode | ||
| unix | ||
| wipy | ||
| README | ||
| run-internalbench.py | ||
| run-multitests.py | ||
| run-natmodtests.py | ||
| run-perfbench.py | ||
| run-tests | ||
| run-tests-exp.py | ||
| run-tests-exp.sh | ||
README
This directory contains tests for various functionality areas of MicroPython. To run all stable tests, run "run-tests" script in this directory. Tests of capabilities not supported on all platforms should be written to check for the capability being present. If it is not, the test should merely output 'SKIP' followed by the line terminator, and call sys.exit() to raise SystemExit, instead of attempting to test the missing capability. The testing framework (run-tests in this directory, test_main.c in qemu_arm) recognizes this as a skipped test. There are a few features for which this mechanism cannot be used to condition a test. The run-tests script uses small scripts in the feature_check directory to check whether each such feature is present, and skips the relevant tests if not. Tests are generally verified by running the test both in MicroPython and in CPython and comparing the outputs. If the output differs the test fails and the outputs are saved in a .out and a .exp file respectively. For tests that cannot be run in CPython, for example because they use the machine module, a .exp file can be provided next to the test's .py file. A convenient way to generate that is to run the test, let it fail (because CPython cannot run it) and then copy the .out file (but not before checking it manually!) When creating new tests, anything that relies on float support should go in the float/ subdirectory. Anything that relies on import x, where x is not a built-in module, should go in the import/ subdirectory.