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Re: [PATCH v2 4/6] s390x/tcg: Fix VECTOR SUBTRACT COMPUTE BORROW INDICAT
From: |
Richard Henderson |
Subject: |
Re: [PATCH v2 4/6] s390x/tcg: Fix VECTOR SUBTRACT COMPUTE BORROW INDICATION |
Date: |
Mon, 21 Oct 2019 08:23:49 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
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 <address@hidden>
> ---
> 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 <address@hidden>
r~
- [PATCH v2 0/6] s390x/tcg: Vector instruction fixes, David Hildenbrand, 2019/10/21
- [PATCH v2 1/6] s390x/tcg: Fix VECTOR MULTIPLY LOGICAL ODD, David Hildenbrand, 2019/10/21
- [PATCH v2 2/6] s390x/tcg: Fix VECTOR MULTIPLY AND ADD *, David Hildenbrand, 2019/10/21
- [PATCH v2 3/6] s390x/tcg: Fix VECTOR SHIFT RIGHT ARITHMETIC BY BYTE, David Hildenbrand, 2019/10/21
- [PATCH v2 6/6] s390x/tcg: Fix VECTOR SUBTRACT WITH BORROW COMPUTE BORROW INDICATION, David Hildenbrand, 2019/10/21
- [PATCH v2 5/6] s390x/tcg: Fix VECTOR SUBTRACT WITH BORROW INDICATION, David Hildenbrand, 2019/10/21
- [PATCH v2 4/6] s390x/tcg: Fix VECTOR SUBTRACT COMPUTE BORROW INDICATION, David Hildenbrand, 2019/10/21
- Re: [PATCH v2 4/6] s390x/tcg: Fix VECTOR SUBTRACT COMPUTE BORROW INDICATION,
Richard Henderson <=
- Re: [PATCH v2 0/6] s390x/tcg: Vector instruction fixes, Cornelia Huck, 2019/10/21