Looks like my idea of what a "borrow" is was wrong. The PoP says:
"If the resulting subtraction results in a carry out of bit zero, a value
of one is placed in the corresponding element of the first operand;
otherwise, a value of zero is placed in the corresponding element"
As clarified by Richard, all we have to do is invert the result.
Fixes: 1ee2d7ba72 ("s390x/tcg: Implement VECTOR SUBTRACT COMPUTE BORROW INDICATION")
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20191021085715.3797-5-david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
23e797749f