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diff --git a/openpower/sv/remap.mdwn b/openpower/sv/remap.mdwn
index 334430cddb7ed96dc0eb72876afc6a9ebe73856f..f92d79b9cc09401e4b271325675475a757e05d95 100644 (file)
--- a/openpower/sv/remap.mdwn
+++ b/openpower/sv/remap.mdwn
@@ -615,16 +615,14 @@ notes from conversations:
 
 Remapping of SUBVL (vec2/3/4) elements is not permitted: the vec2/3/4
 itself must be considered to be the "element".  To perform REMAP
-on the elements of a vec2/3/4, use Swizzle, Indexing, or add one
+on the elements of a vec2/3/4, either use Swizzle, or,
+due to the sub-elements themselves being contiguous, treat them as
+such and use Indexing, or add one
 extra dimension to Matrix REMAP, the inner dimension being the size
 of the Subvector (2, 3, or 4).
 
-The reason for allowing SUBVL Remaps is that some regular patterns using
-Swizzle which would otherwise require multiple explicit instructions
-with 12 bit swizzles encoded in them may be efficently encoded with Remap
-instead.  Not however that Swizzle is *still permitted to be applied*.
-
-An example where SUBVL Remap is appropriate is the Rijndael MixColumns
+Note that Swizzle on Sub-vectors may be applied on top of REMAP.
+Where this is appropriate is the Rijndael MixColumns
 stage:
 
 <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/7/76/AES-MixColumns.svg/600px-AES-MixColumns.svg.png" width="400px" />
@@ -646,18 +644,15 @@ void gmix_column(unsigned char *r) {
     unsigned char b[4];
     unsigned char c;
     unsigned char h;
-    // no swizzle here but still SUBVL.Remap
-    // can be done as vec4 byte-level
-    // elwidth overrides though.
+    // no swizzle here but vec4 byte-level
+    // elwidth overrides can be done though.
     for (c = 0; c < 4; c++) {
         a[c] = r[c];
         h = (unsigned char)((signed char)r[c] >> 7);
         b[c] = r[c] << 1;
         b[c] ^= 0x1B & h; /* Rijndael's Galois field */
     }
-    // SUBVL.Remap still needed here
-    // bytelevel elwidth overrides and vec4
-    // These may then each be 4x 8bit bit Swizzled
+    // These may then each be 4x 8bit Swizzled
     // r0.vec4 = b.vec4
     // r0.vec4 ^= a.vec4.WXYZ
     // r0.vec4 ^= a.vec4.ZWXY
@@ -669,11 +664,6 @@ void gmix_column(unsigned char *r) {
 }
 ```
 
-With the assumption made by the above code that the column bytes have
-already been turned around (vertical rather than horizontal) SUBVL.REMAP
-may transparently fill that role, in-place, without a complex byte-level
-mv operation.
-
 The application of the swizzles allows the remapped vec4 a, b and r
 variables to perform four straight linear 32 bit XOR operations where a
 scalar processor would be required to perform 16 byte-level individual