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From: dthaler1968=40googlemail.com@dmarc.ietf.org
To: <bpf@ietf.org>, <bpf@vger.kernel.org>
Subject: [Bpf] Sign extension ISA question
Date: Tue, 16 Jan 2024 12:38:40 -0800	[thread overview]
Message-ID: <085f01da48bb$fe0c3cb0$fa24b610$@gmail.com> (raw)


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Is there any semantic difference between the following two instructions?

 

{.opcode = BPF_ALU64 | BPF_MOV | BPF_K, .offset = 0, .imm = -1}

 

{.opcode = BPF_ALU64 | BPF_MOVSX | BPF_K, .offset = 32, .imm = -1}

 

>From my reading both of them treat imm as a signed 32-bit number and
sign-extend it to 64 bits.

 

Dave


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             reply	other threads:[~2024-01-16 20:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-16 20:38 dthaler1968=40googlemail.com [this message]
2024-01-16 20:55 ` Sign extension ISA question dthaler1968
2024-01-16 20:55   ` [Bpf] " dthaler1968=40googlemail.com
2024-01-16 22:34   ` Yonghong Song
2024-01-16 22:34     ` [Bpf] " Yonghong Song
2024-01-17  1:56     ` dthaler1968
2024-01-17  1:56       ` [Bpf] " dthaler1968=40googlemail.com
2024-01-17  3:48       ` Yonghong Song
2024-01-17  3:48         ` [Bpf] " Yonghong Song
2024-01-24  2:07         ` Jump instructions clarification dthaler1968
2024-01-24  2:07           ` [Bpf] " dthaler1968=40googlemail.com
2024-01-24 19:33           ` Yonghong Song
2024-01-24 19:33             ` [Bpf] " Yonghong Song
2024-01-26  1:12             ` 64-bit immediate " dthaler1968
2024-01-26  1:12               ` [Bpf] " dthaler1968=40googlemail.com
2024-01-26  5:34               ` Yonghong Song
2024-01-26  5:34                 ` [Bpf] " Yonghong Song
2024-01-26 22:27                 ` dthaler1968
2024-01-26 22:27                   ` [Bpf] " dthaler1968=40googlemail.com
2024-01-27  3:41                   ` Yonghong Song
2024-01-27  3:41                     ` [Bpf] " Yonghong Song
2024-01-27  6:56                     ` dthaler1968
2024-01-27  6:56                       ` [Bpf] " dthaler1968=40googlemail.com

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