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Re: [Qemu-ppc] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l,
From: |
Richard Henderson |
Subject: |
Re: [Qemu-ppc] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l, h} during lvx instruction |
Date: |
Mon, 17 Dec 2018 08:46:17 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 |
On 12/17/18 4:24 AM, Mark Cave-Ayland wrote:
> During review of the previous patch, Richard pointed out an existing bug that
> the writeback to the avr{l,h} registers should be delayed until after any
> exceptions have been raised.
>
> Perform both 64-bit loads into separate temporaries and then write them into
> the avr{l,h} registers together to ensure that this is always the case.
>
> Signed-off-by: Mark Cave-Ayland <address@hidden>
> ---
> target/ppc/translate/vmx-impl.inc.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
I feel a bit silly. There was no bug, since the address is forced to be
aligned on a 16-byte boundary. The second memory access will be to the same
page and cannot trap.
That said, I think the cleanup looks good.
Reviewed-by: Richard Henderson <address@hidden>
r~
- [Qemu-ppc] [RFC PATCH v2 0/9] target/ppc: convert VMX instructions to use TCG vector operations, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 2/9] target/ppc: introduce get_avr64() and set_avr64() helpers for VMX register access, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 6/9] target/ppc: merge ppc_vsr_t and ppc_avr_t union types, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l, h} during lvx instruction, Mark Cave-Ayland, 2018/12/17
- Re: [Qemu-ppc] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l, h} during lvx instruction,
Richard Henderson <=
- [Qemu-ppc] [RFC PATCH v2 5/9] target/ppc: switch FPR, VMX and VSX helpers to access data directly from cpu_env, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 1/9] target/ppc: introduce get_fpr() and set_fpr() helpers for FP register access, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 3/9] target/ppc: introduce get_cpu_vsr{l, h}() and set_cpu_vsr{l, h}() helpers for VSR register access, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 9/9] target/ppc: convert vaddu[b, h, w, d] and vsubu[b, h, w, d] over to use vector operations, Mark Cave-Ayland, 2018/12/17
- [Qemu-ppc] [RFC PATCH v2 7/9] target/ppc: move FP and VMX registers into aligned vsr register array, Mark Cave-Ayland, 2018/12/17