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X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Apr 2023 13:19:41.8829 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: aaa9da9c-51e1-42e0-5891-08db35d86a86 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[63.35.35.123];Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-AuthSource: AM7EUR03FT054.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU0PR08MB9464 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,FORGED_SPF_HELO,KAM_DMARC_NONE,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,RCVD_IN_VALIDITY_RPBL,SPF_HELO_PASS,SPF_NONE,TXREP,UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Hi,=0A= =0A= > Maybe we can use a custom C implementation (like RISC-V) as well. =A0But= =0A= > strictly speaking the RISC-V syscall.c is invoking undefined behavior=0A= > (like my proposal) so I agree with assembly here.=0A= =0A= How does assembly code not invoke the exact same undefined behaviour?=0A= In both cases you rely on variable arguments being passed in the same=0A= way as integer args - this is true in many ABIs. The goal is to avoid intro= ducing=0A= unnecessary assembly and use generic implementations where possible.=0A= =0A= So if that C version works as well as assembler on LoongArch and assuming= =0A= that bare syscall() performance is essential, then why not use it?=0A= =0A= Cheers,=0A= Wilco=