aarch64: vp9mc: Simplify the extmla macro parameters

Fold the field lengths into the macro.

This makes the macro invocations much more readable, when the
lines are shorter.

This also makes it easier to use only half the registers within
the macro.

This is cherrypicked from libav commit
5e0c215.

Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/aarch64/vp9mc_neon.S

@@ -193,41 +193,41 @@ endfunc
 // for size >= 16), and multiply-accumulate into dst1 and dst3 (or
 // dst1-dst2 and dst3-dst4 for size >= 16)
 .macro extmla dst1, dst2, dst3, dst4, src1, src2, src3, src4, src5, src6, offset, size
-        ext             v20.16b, \src1, \src2, #(2*\offset)
-        ext             v22.16b, \src4, \src5, #(2*\offset)
+        ext             v20.16b, \src1\().16b, \src2\().16b, #(2*\offset)
+        ext             v22.16b, \src4\().16b, \src5\().16b, #(2*\offset)
 .if \size >= 16
-        mla             \dst1, v20.8h, v0.h[\offset]
-        ext             v21.16b, \src2, \src3, #(2*\offset)
-        mla             \dst3, v22.8h, v0.h[\offset]
-        ext             v23.16b, \src5, \src6, #(2*\offset)
-        mla             \dst2, v21.8h, v0.h[\offset]
-        mla             \dst4, v23.8h, v0.h[\offset]
+        mla             \dst1\().8h, v20.8h, v0.h[\offset]
+        ext             v21.16b, \src2\().16b, \src3\().16b, #(2*\offset)
+        mla             \dst3\().8h, v22.8h, v0.h[\offset]
+        ext             v23.16b, \src5\().16b, \src6\().16b, #(2*\offset)
+        mla             \dst2\().8h, v21.8h, v0.h[\offset]
+        mla             \dst4\().8h, v23.8h, v0.h[\offset]
 .else
-        mla             \dst1, v20.8h, v0.h[\offset]
-        mla             \dst3, v22.8h, v0.h[\offset]
+        mla             \dst1\().8h, v20.8h, v0.h[\offset]
+        mla             \dst3\().8h, v22.8h, v0.h[\offset]
 .endif
 .endm
 // The same as above, but don't accumulate straight into the
 // destination, but use a temp register and accumulate with saturation.
 .macro extmulqadd dst1, dst2, dst3, dst4, src1, src2, src3, src4, src5, src6, offset, size
-        ext             v20.16b, \src1, \src2, #(2*\offset)
-        ext             v22.16b, \src4, \src5, #(2*\offset)
+        ext             v20.16b, \src1\().16b, \src2\().16b, #(2*\offset)
+        ext             v22.16b, \src4\().16b, \src5\().16b, #(2*\offset)
 .if \size >= 16
         mul             v20.8h, v20.8h, v0.h[\offset]
-        ext             v21.16b, \src2, \src3, #(2*\offset)
+        ext             v21.16b, \src2\().16b, \src3\().16b, #(2*\offset)
         mul             v22.8h, v22.8h, v0.h[\offset]
-        ext             v23.16b, \src5, \src6, #(2*\offset)
+        ext             v23.16b, \src5\().16b, \src6\().16b, #(2*\offset)
         mul             v21.8h, v21.8h, v0.h[\offset]
         mul             v23.8h, v23.8h, v0.h[\offset]
 .else
         mul             v20.8h, v20.8h, v0.h[\offset]
         mul             v22.8h, v22.8h, v0.h[\offset]
 .endif
-        sqadd           \dst1, \dst1, v20.8h
-        sqadd           \dst3, \dst3, v22.8h
+        sqadd           \dst1\().8h, \dst1\().8h, v20.8h
+        sqadd           \dst3\().8h, \dst3\().8h, v22.8h
 .if \size >= 16
-        sqadd           \dst2, \dst2, v21.8h
-        sqadd           \dst4, \dst4, v23.8h
+        sqadd           \dst2\().8h, \dst2\().8h, v21.8h
+        sqadd           \dst4\().8h, \dst4\().8h, v23.8h
 .endif
 .endm
 
@@ -291,13 +291,13 @@ function \type\()_8tap_\size\()h_\idx1\idx2
         mul             v2.8h,  v5.8h,  v0.h[0]
         mul             v25.8h, v17.8h, v0.h[0]
 .endif
-        extmla          v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, 1,     \size
-        extmla          v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, 2,     \size
-        extmla          v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, \idx1, \size
-        extmla          v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, 5,     \size
-        extmla          v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, 6,     \size
-        extmla          v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, 7,     \size
-        extmulqadd      v1.8h,  v2.8h,  v24.8h, v25.8h, v4.16b,  v5.16b,  v6.16b,  v16.16b, v17.16b, v18.16b, \idx2, \size
+        extmla          v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, 1,     \size
+        extmla          v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, 2,     \size
+        extmla          v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, \idx1, \size
+        extmla          v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, 5,     \size
+        extmla          v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, 6,     \size
+        extmla          v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, 7,     \size
+        extmulqadd      v1,  v2,  v24, v25, v4,  v5,  v6,  v16, v17, v18, \idx2, \size
 
         // Round, shift and saturate
         sqrshrun        v1.8b,   v1.8h,  #7