Improvements to ARM small Karatsuba muls #34
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The new functions ARM_MACRO_SIM_ABBREV_TAC and X86_MACRO_SIM_ABBREV_TAC are designed as analogs of ...SUBROUTINE_SIM_TAC but are a bit more flexible (allowing the subgoal to be generated from a template and proved per instance instead of requiring a general theorem) as well as doing a bit more work to infer parameters from the current state. This also tweaks away the need to use "word(pc + 0)" instead of just "word pc" in subroutine simulation, and makes a few other changes to clean up loading in conjunction with other theories: - Use fully-expanded form of the p_25519 = 2^255 - 19 constant as in https://github.com/jrh13/hol-light/blob/master/EC/curve25519.ml - Rename the x86 mask registers "k1" -> "kmask1" etc. (otherwise they steal too much namespace for something not currently used). - Partially evaluate some quotations in NONOVERLAPPING_TAC. Less brittle and slightly faster as a result.
The ARM functions that involve multiplying 4-digit (256-bit) numbers at the top level previously used an integrated "arbitrary degree Karatsuba" algorithm. This switches from the ADK approach to a classic 2-level Karatsuba, which seems a slight performance improvement on many relevant microarchitectures. The _alt forms designed for faster microarchitectures are unchanged and still use straightforward schoolbook arrays.
nebeid
approved these changes
Jun 10, 2022
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