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authorSerge Vakulenko <serge.vakulenko@gmail.com>2015-07-05 23:14:50 -0700
committerLeon Alrae <leon.alrae@imgtec.com>2015-09-18 09:20:48 +0100
commitceb0ee147df35adc7b705da1c84a4624c9cabb21 (patch)
treea87800759b1e4d48231346889f882d3afbb8401c /util/qemu-error.c
parentb307446e04232b3a87e9da04886895a8e5a4a407 (diff)
downloadfocaccia-qemu-ceb0ee147df35adc7b705da1c84a4624c9cabb21.tar.gz
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pic32: use LCG algorithm for generated random index of TLBWR instruction
The LFSR algorithm, used for generating random TLB indexes for TLBWR
instruction, was inclined to produce a degenerate sequence in some cases.
For example, for 16-entry TLB size and Wired=1, it gives: 15, 6, 7, 2,
7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2...
When replaced with LCG algorithm from ISO/IEC 9899 standard, the sequence
looks much better, with about the same computational effort needed.

Signed-off-by: Serge Vakulenko <serge.vakulenko@gmail.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Diffstat (limited to 'util/qemu-error.c')
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