Bugfixes to fp_prime_random_ex #4
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When we ask to generate a prime whose size is a multiple of 8, the code wrongly computes the mask as 0x00 instead of 0xFF, so the generated prime always has the MSB set to 0x80 (the highest bit is OR'ed later in the code).
This is the only instance of dynamic memory in TFM. It can be avoided by writing directly into the dp[] array, and it does not violate C aliasing rules which specifically allow access on objects through char*. It does not matter the platform-specific representation of digits since we are filling them with random data anyway.
There are potential issues with weird platforms were not all bits of a fp_digit are used (padding bits), plus it makes it harder to do reproducible testing of algorithms.
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Updated after mailing-list reviews: remove possibly unportable code, and fixed more bugs discovered by accurate testing. |
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This needs rebasing and some love. Seeing that this is a really old PR, I'm making a reboot PR and doing the work |
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Reboot in #39, closing this |
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This branch contains some fixes to fp_prime_random_ex. See the specific commits. Specifically: