These instructions use addressing with a "base address", meaning
that if register r0 is used, it is always treated as zero, no matter
what value is stored in the register. So we have to make sure not
to use register r0 for these instructions in our tests. There was
no problem with GCC so far since it seems to always pick other
registers by default, but Clang likes to chose register r0, too,
so we have to use the "a" constraint to make sure that it does
not pick r0 here.
Message-Id: <20220301093911.1450719-1-thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
PACK fails on the test from the Principles of Operation: F1F2F3F4
becomes 0000234C instead of 0001234C due to an off-by-one error.
Furthermore, it overwrites one extra byte to the left of F1.
If len_dest is 0, then we only want to flip the 1st byte and never loop
over the rest. Therefore, the loop condition should be > and not >=.
If len_src is 1, then we should flip the 1st byte and pack the 2nd.
Since len_src is already decremented before the loop, the first
condition should be >=, and not >.
Likewise for len_src == 2 and the second condition.
Signed-off-by: Pavel Zbitskiy <pavel.zbitskiy@gmail.com>
Message-Id: <20180821025104.19604-7-pavel.zbitskiy@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Thomas Huth
Pavel Zbitskiy