From: Richard Henderson <richard.henderson@linaro.org>
To: David Hildenbrand <david@redhat.com>, qemu-devel@nongnu.org
Cc: Ivan Warren <ivan@vmfacility.fr>,
qemu-s390x@nongnu.org, Cornelia Huck <cohuck@redhat.com>,
Thomas Huth <thuth@redhat.com>
Subject: Re: [PATCH v2 4/6] s390x/tcg: Fix VECTOR SUBTRACT COMPUTE BORROW INDICATION
Date: Mon, 21 Oct 2019 08:23:49 -0700 [thread overview]
Message-ID: <f35bd898-b587-cdfa-07cd-a94f54a4518f@linaro.org> (raw)
In-Reply-To: <20191021085715.3797-5-david@redhat.com>
On 10/21/19 1:57 AM, David Hildenbrand wrote:
> 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: 1ee2d7ba72f6 ("s390x/tcg: Implement VECTOR SUBTRACT COMPUTE BORROW INDICATION")
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> target/s390x/translate_vx.inc.c | 7 ++++---
> target/s390x/vec_int_helper.c | 2 +-
> 2 files changed, 5 insertions(+), 4 deletions(-)
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
r~
next prev parent reply other threads:[~2019-10-21 15:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 8:57 [PATCH v2 0/6] s390x/tcg: Vector instruction fixes David Hildenbrand
2019-10-21 8:57 ` [PATCH v2 1/6] s390x/tcg: Fix VECTOR MULTIPLY LOGICAL ODD David Hildenbrand
2019-10-21 8:57 ` [PATCH v2 2/6] s390x/tcg: Fix VECTOR MULTIPLY AND ADD * David Hildenbrand
2019-10-21 8:57 ` [PATCH v2 3/6] s390x/tcg: Fix VECTOR SHIFT RIGHT ARITHMETIC BY BYTE David Hildenbrand
2019-10-21 8:57 ` [PATCH v2 4/6] s390x/tcg: Fix VECTOR SUBTRACT COMPUTE BORROW INDICATION David Hildenbrand
2019-10-21 15:23 ` Richard Henderson [this message]
2019-10-21 8:57 ` [PATCH v2 5/6] s390x/tcg: Fix VECTOR SUBTRACT WITH " David Hildenbrand
2019-10-21 15:23 ` Richard Henderson
2019-10-21 8:57 ` [PATCH v2 6/6] s390x/tcg: Fix VECTOR SUBTRACT WITH BORROW COMPUTE " David Hildenbrand
2019-10-21 15:24 ` Richard Henderson
2019-10-21 16:01 ` [PATCH v2 0/6] s390x/tcg: Vector instruction fixes Cornelia Huck
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