(no commit message)

diff --git a/openpower/sv/svp64/appendix.mdwn b/openpower/sv/svp64/appendix.mdwn
index 76d01a10b7e39e5906f37a3a3518a7c25e73620b..3e4699da7cb1465932f06efd99dd5e5013037c54 100644 (file)
--- a/openpower/sv/svp64/appendix.mdwn
+++ b/openpower/sv/svp64/appendix.mdwn
@@ -304,16 +304,17 @@ is not actually a Vector ISA: it is a loop-abstraction-concept that
 is applied *in general* to Scalar operations, just like the x86
 `REP` instruction (if put on steroids).
 
-# EXTRA Pack/Unpack Modes
+# EXTRA Pack/Unpack bits
 
 The pack/unpack concept of VSX `vpack` is abstracted out as a Sub-Vector
-reordering Schedule, named `RM-2P-1S1D-PU`.
-The usual RM-2P-1S1D is reduced from EXTRA3 to EXTRA2, making
-room for 2 extra bits that enable either "packing" or "unpacking"
+reordering Schedule.
+Two bits in the `RM` field 
+enable either "packing" or "unpacking"
 on the subvectors vec2/3/4.
 
-Illustrating a
-"normal" SVP64 operation with `SUBVL!=1:` (assuming no elwidth overrides):
+First, llustrating a
+"normal" SVP64 operation with `SUBVL!=1:` (assuming no elwidth overrides),
+note that the VL loop is outer and the SUBVL loop inner:
 
     def index():
         for i in range(VL):
@@ -323,7 +324,9 @@ Illustrating a
     for idx in index():
         operation_on(RA+idx)
 
-For pack/unpack (again, no elwidth overrides):
+For pack/unpack (again, no elwidth overrides), note that now there is the
+option to swap the SUBVL and VL loop orders.
+In effect the Pack/Unpack performs a Transpose of the subvector elements:
 
     # yield an outer-SUBVL or inner VL loop with SUBVL
     def index_p(outer):
@@ -358,10 +361,11 @@ are Sub-elements 2.
 
 Setting of both `PACK_en` and `UNPACK_en` is neither prohibited nor
 `UNDEFINED` because the reordering is fully deterministic, and
-additional REMAP reordering may be applied. For Matrix this would
+additional REMAP reordering may be applied. Combined with
+Matrix REMAP this would
 give potentially up to 4 Dimensions of reordering.
 
-Pack/Unpack applies to mv operations, mv.swizzle,
+Pack/Unpack applies primarily to mv operations, mv.swizzle,
 and some other single-source
 single-destination operations such as Indexed LD/ST and extsw.
 [[sv/mv.swizzle]] has a slightly different pseudocode algorithm