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author | Serge Vakulenko <serge.vakulenko@gmail.com> | 2015-07-05 23:14:50 -0700 |
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committer | Leon Alrae <leon.alrae@imgtec.com> | 2015-09-18 09:20:48 +0100 |
commit | ceb0ee147df35adc7b705da1c84a4624c9cabb21 (patch) | |
tree | a87800759b1e4d48231346889f882d3afbb8401c /target-openrisc/exception_helper.c | |
parent | b307446e04232b3a87e9da04886895a8e5a4a407 (diff) | |
download | qemu-ceb0ee147df35adc7b705da1c84a4624c9cabb21.zip qemu-ceb0ee147df35adc7b705da1c84a4624c9cabb21.tar.gz qemu-ceb0ee147df35adc7b705da1c84a4624c9cabb21.tar.bz2 |
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 'target-openrisc/exception_helper.c')
0 files changed, 0 insertions, 0 deletions