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Re: [qemu-s390x] [PATCH v1] s390x: Add floating-point extension facility
From: |
David Hildenbrand |
Subject: |
Re: [qemu-s390x] [PATCH v1] s390x: Add floating-point extension facility to "qemu" cpu model |
Date: |
Tue, 12 Feb 2019 12:04:35 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
On 12.02.19 12:02, David Hildenbrand wrote:
> The floating-point extension facility implemented certain changes to
> BFP, HFP and DFP instructions.
>
> As we don't implement HFP/DFP, we can ignore those completely. Related
> to BFP, the changes include
> - SET BFP ROUNDING MODE (SRNMB) instruction
> - BFP-rounding-mode field in the FPC register is changed to 3 bits
> - CONVERT FROM LOGICAL instructions
> - CONVERT TO LOGICAL instructions
> - Changes (rounding mode + XxC) added to
> -- CONVERT TO FIXED
> -- CONVERT FROM FIXED
> -- LOAD FP INTEGER
> -- LOAD ROUNDED
> -- DIVIDE TO INTEGER
>
> For TCG, we don't implement DIVIDE TO INTEGER, and it is harder to
> implement, so skip that. Also, as we don't implement PFPO, we can skip
> changes to that as well. The other parts are now implemented, we can
> indicate the facility.
>
> z14 PoP mentiones that "The floating-point extension facility is installed
> in the z/Architecture architectural mode. When bit 37 is one, bit 42 is
> also one.", meaning that the DFP (decimal-floating-point) facility also
> has to be inidicated. We can ignore that for now.
>
> Signed-off-by: David Hildenbrand <address@hidden>
This is the same patch as 15/15, refer to 0/15 as cover letter instead.
--
Thanks,
David / dhildenb
- Re: [qemu-s390x] [Qemu-devel] [PATCH v1 10/15] s390x/tcg: Refactor saving/restoring the bfp rounding mode, (continued)
- [qemu-s390x] [PATCH v1 11/15] s390x/tcg: Prepare for IEEE-inexact-exception control (XxC), David Hildenbrand, 2019/02/12
- [qemu-s390x] [PATCH v1 12/15] s390x/tcg: Implement XxC and checks for most FP instructions, David Hildenbrand, 2019/02/12
- [qemu-s390x] [PATCH v1 13/15] s390x/tcg: Implement rounding mode and XxC for LOAD ROUNDED, David Hildenbrand, 2019/02/12
- [qemu-s390x] [PATCH v1 14/15] s390x/tcg: Handle all rounding modes overwritten by BFP instructions, David Hildenbrand, 2019/02/12
- Re: [qemu-s390x] [PATCH v1] s390x: Add floating-point extension facility to "qemu" cpu model,
David Hildenbrand <=
- [qemu-s390x] [PATCH v1 15/15] s390x: Add floating-point extension facility to "qemu" cpu model, David Hildenbrand, 2019/02/12