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2001
IEEE

Architectural Enhancements for Fast Subword Permutations with Repetitions in Cryptographic Applications

10 years 24 days ago
Architectural Enhancements for Fast Subword Permutations with Repetitions in Cryptographic Applications
We propose two new instructions, swperm and sieve, that can be used to efficiently complete an arbitrary bit-level permutation of an n-bit word with or without repetitions. Permutations with repetitions are rearrangements of an ordered set in which elements may replace other elements in the set; such permutations are useful in cryptographic algorithms. On a 4-way superscalar processor, an arbitrary 64-bit permutation with repetitions of 1-bit subwords can be completed in 11 instructions and only 4 cycles using the two proposed instructions. For subwords of size 4 bits or greater, an arbitrary permutation with repetitions of a 64-bit register can be completed in a single cycle using a single swperm instruction. This improves upon previous permutation instruction proposals that require log(r) sequential instructions to permute r subwords of a 64-bit word without repetitions. Our method requires fewer instructions to permute 4-bit or larger subwords packed in a 64-bit register and fewer ...
John Patrick McGregor, Ruby B. Lee
Added 16 Mar 2010
Updated 16 Mar 2010
Type Conference
Year 2001
Where ICCD
Authors John Patrick McGregor, Ruby B. Lee
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