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Re: [Qemu-devel] [PATCH 05/28] target/riscv: Convert RVXI fence insns to
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From: |
Richard Henderson |
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Subject: |
Re: [Qemu-devel] [PATCH 05/28] target/riscv: Convert RVXI fence insns to decodetree |
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Date: |
Fri, 12 Oct 2018 12:17:58 -0700 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 |
On 10/12/18 10:30 AM, Bastian Koppelmann wrote:
> +%pred 24:4
> +%succ 20:4
...
> address@hidden ................................
...
> address@hidden .... .... .... ..... ... ..... ....... %pred %succ
...
> +fence 0000 .... .... 00000 000 00000 0001111 @fence
> +fence_i 000000000000 00000 001 00000 0001111 @noargs
@noargs is useless, even as documentation, since by its omission there are no
arguments.
Also, "the unused fields in the FENCE instruction, imm[11:8], rs1, and rd, are
reserved for finer-grain fences in future extensions. For forward
compatibility, base implementations shall ignore these fields, and standard
software shall zero these fields."
Therefore "-" not "0" in the relevant portions. And for clarity I would simply
fold it all together as
fence ---- pred:4 succ:4 ----- 000 ----- 0001111
fence_i ---- ---- ---- ----- 001 ----- 0001111
Or just use "@i", which is the underlying format and ignore the rs1 and rd
fields in the trans_ expanders, and pull pred+succ out of imm there.
r~
- Re: [Qemu-devel] [PATCH 03/28] target/riscv: Convert RVXI load/store insns to decodetree, (continued)
- [Qemu-devel] [PATCH 04/28] target/riscv: Convert RVXI arithmetic insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 01/28] targer/riscv: Activate decodetree and implemnt LUI & AUIPC, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 07/28] target/riscv: Convert RVXM insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 06/28] target/riscv: Convert RVXI csr insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 05/28] target/riscv: Convert RVXI fence insns to decodetree, Bastian Koppelmann, 2018/10/12
- Re: [Qemu-devel] [PATCH 05/28] target/riscv: Convert RVXI fence insns to decodetree,
Richard Henderson <=
- [Qemu-devel] [PATCH 02/28] target/riscv: Convert RVXI branch insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 08/28] target/riscv: Convert RV32A insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 11/28] target/riscv: Convert RV64F insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 10/28] target/riscv: Convert RV32F insns to decodetree, Bastian Koppelmann, 2018/10/12
- [Qemu-devel] [PATCH 14/28] target/riscv: Convert RV priv insns to decodetree, Bastian Koppelmann, 2018/10/12