Re: [PATCH 0/4] target/s390x: CC fixes

[David Hildenbrand]

On 31.10.23 06:32, Ilya Leoshkevich wrote:
> Hi,
>
> This series fixes two issues with updating CC. David was suggesting a
> bigger rewrite [1], but I did not dare do this (yet). Instead, these

I started coding that up but was distracted by other things; last time I 
looked at that, I concluded that the way we are calculating the carry in 
not suitable when we're doing two additions (like ADD LOGICAL WITH CARRY).

In addition, the way cout_addu32/cout_addu64 relies on cc_src/cc_dst is 
wrong in some occurrences.

> are targeted fixes: patch 1 helps with installing Fedora, and patch 3
> addresses something I noticed when reviewing the code. Patches 2 and 4
> are tests.

I assume you are only scratching the surface with your fixes and we 
might be better off just doing CC_OP_ADDU / CC_OP_SUBU like CC_OP_ADD_32 
/ CC_OP_ADD_64 / ... to fix all issues involved.

> Best regards,
> Ilya
>
> [1] https://gitlab.com/qemu-project/qemu/-/issues/1865#note_1545060658
>
> Ilya Leoshkevich (4):
>    target/s390x: Fix CLC corrupting cc_src
>    tests/tcg/s390x: Test CLC with inaccessible second operand
>    target/s390x: Fix LAALG not updating cc_src
>    tests/tcg/s390x: Test LAALG with negative cc_src
>
>   target/s390x/tcg/translate.c    | 10 ++++---
>   tests/tcg/s390x/Makefile.target |  2 ++
>   tests/tcg/s390x/clc.c           | 48 +++++++++++++++++++++++++++++++++
>   tests/tcg/s390x/laalg.c         | 27 +++++++++++++++++++
>   4 files changed, 84 insertions(+), 3 deletions(-)
>   create mode 100644 tests/tcg/s390x/clc.c
>   create mode 100644 tests/tcg/s390x/laalg.c

--
Cheers,

David / dhildenb