From: Jeff Law <jeffreyalaw@gmail.com>
To: Philipp Tomsich <philipp.tomsich@vrull.eu>, binutils@sourceware.org
Cc: Kito Cheng <kito.cheng@sifive.com>,
Nelson Chu <nelson.chu@sifive.com>,
Christoph Muellner <christoph.muellner@vrull.eu>
Subject: Re: [RFC PATCH v1] RISC-V: Support Zicond extension
Date: Wed, 25 Jan 2023 17:26:47 -0700 [thread overview]
Message-ID: <7dfcdb8b-f8ba-f0ae-b71f-f6fef1acac13@gmail.com> (raw)
In-Reply-To: <20230121002935.1139281-1-philipp.tomsich@vrull.eu>
On 1/20/23 17:29, Philipp Tomsich wrote:
> *** Zicond is not FROZEN at this time. Do not merge until FROZEN. ***
>
> This implements the Zicond (conditional integer operations) extension,
> as of version 1.0-draft-20230120.
>
> The Zicond extension acts as a building block for branchless sequences
> including conditional-arithmetic, conditional-logic and
> conditional-select/move.
> The following instructions constitute Zicond:
> - czero.eqz rd, rs1, rs2 => rd = (rs2 == 0) ? 0 : rs1
> - czero.nez rd, rs1, rs2 => rd = (rs2 != 0) ? 0 : rs1
>
> See
> https://github.com/riscv/riscv-zicond/releases/download/v1.0-draft-20230120/riscv-zicond_1.0-draft-20230120.pdf
> for the proposed specification and usage details.
>
> bfd/ChangeLog:
>
> * elfxx-riscv.c (riscv_multi_subset_supports): Recognize
> INSN_CLASS_XVENTANACONDOPS.
> (riscv_multi_subset_supports_ext): Recognize
> INSN_CLASS_XVENTANACONDOPS,
>
> gas/ChangeLog:
>
> * testsuite/gas/riscv/zicond.d: New test.
> * testsuite/gas/riscv/zicond.s: New test.
>
> include/ChangeLog:
>
> * opcode/riscv-opc.h (MATCH_CZERO_EQZ): Define.
> (MASK_CZERO_EQZ): Define.
> (MATCH_CZERO_NEZ): Define,
> (MASK_CZERO_NEZ): Define.
> (DECLARE_INSN): Add czero.eqz and czero.nez.
> * opcode/riscv.h (enum riscv_insn_class): Add
> INSN_CLASS_ZICOND
>
> opcodes/ChangeLog:
>
> * riscv-opc.c: Add czero.eqz and czero.nez.
Given this extension is derived from the Ventana condops extension, I
may be somewhat biased. The mnemonics and encoding is obviously
different, but the behavior is the same (perhaps differing in timing
characteristics, but I think that's outside of what we care about here).
I assume nobody cares about gdbsim, so nothing to do there. With that
assumption this is fine to go forward once the spec freezes.
jeff
next prev parent reply other threads:[~2023-01-26 0:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-21 0:29 Philipp Tomsich
2023-01-26 0:26 ` Jeff Law [this message]
2023-01-26 1:02 ` Andrew Waterman
2023-03-01 1:58 ` Nelson Chu
2023-03-01 2:03 ` Palmer Dabbelt
2023-06-19 14:21 ` Philipp Tomsich
2023-06-21 4:25 ` Jeff Law
2023-06-21 4:38 ` Palmer Dabbelt
2023-06-27 13:27 ` Jeff Law
2023-06-27 14:32 ` Philipp Tomsich
2023-06-27 23:12 ` Jeff Law
2023-06-27 23:33 ` Palmer Dabbelt
2023-06-27 14:48 ` Palmer Dabbelt
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