>-----Original Message----- >From: ffmpeg-devel-boun...@ffmpeg.org [mailto:ffmpeg-devel-boun...@ffmpeg.org] >On Behalf Of >jiaxun.y...@flygoat.com >Sent: Tuesday, June 9, 2020 1:59 PM >To: Shiyou Yin; 'FFmpeg development discussions and patches' >Subject: Re: [FFmpeg-devel] [PATCH v4 2/4] libavutils: Add parse_r helper for >MIPS > > > >于 2020年6月9日 GMT+08:00 下午1:43:58, Shiyou Yin <yinshiyou...@loongson.cn> 写到: >>>-----Original Message----- >>>From: jiaxun.y...@flygoat.com [mailto:jiaxun.y...@flygoat.com] >>>Sent: Tuesday, June 9, 2020 2:03 AM >>>To: FFmpeg development discussions and patches; Shiyou Yin; 'FFmpeg >>>development discussions and >>>patches' >>>Subject: Re: [FFmpeg-devel] [PATCH v4 2/4] libavutils: Add parse_r helper >>>for MIPS >>> >>> >>> >>>于 2020年6月8日 GMT+08:00 下午4:38:58, Shiyou Yin <yinshiyou...@loongson.cn> 写到: >>>>>-----Original Message----- >>>>>From: ffmpeg-devel-boun...@ffmpeg.org >>>>>[mailto:ffmpeg-devel-boun...@ffmpeg.org] On Behalf Of >>>>>Jiaxun Yang >>>>>Sent: Monday, June 8, 2020 11:30 AM >>>>>To: ffmpeg-devel@ffmpeg.org >>>>>Cc: yinshi...@loongson.cn; Jiaxun Yang >>>>>Subject: [FFmpeg-devel] [PATCH v4 2/4] libavutils: Add parse_r helper for >>>>>MIPS >>>>> >>> >>>[...] >>> >>>>In inline assembler, we can add asmSymbolicName in Input/ Output Operands, >>>>format: >>>>[ [asmSymbolicName] ] constraint (cExpression) >>>>[ [asmSymbolicName] ] constraint (cVariableName) >>> >>>Could you expand it? >>>I'm not really sure how that related to our case. >>> >>>I'm trying to use raw opcode in inline assembly and I need >>>this helper to deal with oprands in raw opcode. >>> >>>Thanks! >>> >> >>For the raw opcode case, another proposal for your reference. >>static uint32_t read_cpucfg_2(uint32_t reg) >>{ >> register uint32_t input __asm__ ("t0") = reg; >> register uint32_t __res __asm__ ("t1") = 0; >> __asm__ volatile( >> ".insn \n\t" >> ".word (0xc9084918) \n\t" >> ); >> return __res; > >Actually this is not always safe. >t0 and t1 might be clobbered by compiler optimization. > >>} > >I need this helper to ensure the register usage is guarded by >compiler's allocation system. >
Got it, than LGTM. >-- >Jiaxun Yang >_______________________________________________ >ffmpeg-devel mailing list >ffmpeg-devel@ffmpeg.org >https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > >To unsubscribe, visit link above, or email >ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
