[FFmpeg-devel] [PATCH v3 2/2] swscale/aarch64: add hscale specializations

[Martin Storsjö]

On Thu, 26 May 2022, J. Dekker wrote:

>> +
>> +        // gather random access data from src into contiguous memory
>> +        ldr                 w8, [x3, w8, UXTW]          // src[filterPos[idx + 0]][0..3]
> Current asm code has lowercase uxtw, would prefer to keep it consistent.
>> +        ldr                 w9, [x3, w9, UXTW]          // src[filterPos[idx + 1]][0..3]
>> +        ldr                 w10, [x3, w10, UXTW]        // src[filterPos[idx + 2]][0..3]
>> +        ldr                 w11, [x3, w11, UXTW]        // src[filterPos[idx + 3]][0..3]
>> +        ldr                 w12, [x3, w12, UXTW]        // src[filterPos[idx + 4]][0..3]
>> +        ldr                 w13, [x3, w13, UXTW]        // src[filterPos[idx + 5]][0..3]
>> +        ldr                 w14, [x3, w14, UXTW]        // src[filterPos[idx + 6]][0..3]
>> +        ldr                 w15, [x3, w15, UXTW]        // src[filterPos[idx + 7]][0..3]
>> +        stp                 w8, w9, [sp]                // *scratch_mem = { src[filterPos[idx + 0]][0..3], src[filterPos[idx + 1]][0..3] }
>> +        stp                 w10, w11, [sp, #8]          // *scratch_mem = { src[filterPos[idx + 2]][0..3], src[filterPos[idx + 3]][0..3] }
>> +        stp                 w12, w13, [sp, #16]         // *scratch_mem = { src[filterPos[idx + 4]][0..3], src[filterPos[idx + 5]][0..3] }
>> +        stp                 w14, w15, [sp, #24]         // *scratch_mem = { src[filterPos[idx + 6]][0..3], src[filterPos[idx + 7]][0..3] }
>> +
>> +1:
>> +        ld4                 {v16.8B, v17.8B, v18.8B, v19.8B}, [sp] // transpose 8 bytes each from src into 4 registers
> Same with format specifiers being lower case, i.e. v16.8b

That's indeed the convention for most of our code, but we do have some 
amount of code using uppercase for these too. In particular, this file 
itself uses uppercase for such things so far.

Ideally we would reformat those files to use consistent styles, but until 
then I don't have a very strong opinion about it (we can add it matching 
the surrounding code and then reformat it all later, or add the new code 
in the generally preferred style).

// Martin