Memory procedures

Module std::mem contains a set of utility procedures for working with random access memory.

Procedure	Description
memcopy	Copies n words from read_ptr to write_ptr. Stack transition looks as follows: [n, read_ptr, write_ptr, …] -> […] Cycles: 15 + 16n
pipe_double_words_to_memory	Moves an even number of words from the advice stack to memory. Input: [C, B, A, write_ptr, end_ptr, …] Output: [C, B, A, write_ptr, …] Where: - The words C, B, and A are the RPO hasher state - A is the capacity - C, B are the rate portion of the state - The value num_words = end_ptr - write_ptr must be positive and even Cycles: 10 + 9 * num_words / 2
pipe_words_to_memory	Moves an arbitrary number of words from the advice stack to memory. Input: [num_words, write_ptr, …] Output: [HASH, write_ptr’, …] Where HASH is the sequential RPO hash of all copied words. Cycles: - Even num_words: 48 + 9 * num_words / 2 - Odd num_words: 65 + 9 * round_down(num_words / 2)
pipe_preimage_to_memory	Moves an arbitrary number of words from the advice stack to memory and asserts it matches the commitment. Input: [num_words, write_ptr, COM, …] Output: [write_ptr’, …] Cycles: - Even num_words: 58 + 9 * num_words / 2 - Odd num_words: 75 + 9 * round_down(num_words / 2)

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Last update: January 17, 2024

Authors: avenbreaks