[FFmpeg-devel] [PATCH v4 2/4] libavutils: Add parse_r helper for MIPS

Shiyou Yin yinshiyou-hf at loongson.cn
Tue Jun 9 08:43:58 EEST 2020


>-----Original Message-----
>From: jiaxun.yang at flygoat.com [mailto:jiaxun.yang at 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-hf at loongson.cn> 写到:
>>>-----Original Message-----
>>>From: ffmpeg-devel-bounces at ffmpeg.org [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of
>>>Jiaxun Yang
>>>Sent: Monday, June 8, 2020 11:30 AM
>>>To: ffmpeg-devel at ffmpeg.org
>>>Cc: yinshiyou at 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;
}




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