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diff --git a/openpower/sv/rfc/ls008.mdwn b/openpower/sv/rfc/ls008.mdwn
index 8e8d6dbbe22a0ae6e574d348ef01e15819578a1c..03217387b217e1fcddd94fc47c3216d2d75cb832 100644 (file)
--- a/openpower/sv/rfc/ls008.mdwn
+++ b/openpower/sv/rfc/ls008.mdwn
@@ -277,18 +277,27 @@ field may only be set **statically** as an immediate, by the `setvl` instruction
 It may **NOT** be set dynamically from a register.  Compiler writers and assembly
 programmers are expected to perform static register file analysis, subdivision,
 and allocation and only utilise `setvl`. Direct writing to SVSTATE in order to
-"bypass" this Note could, in less-advanced implementations, potentially cause stalling.
+"bypass" this Note could, in less-advanced implementations, potentially cause stalling,
+particularly if SVP64 instructions are issued directly after the `mtspr` to SVSTATE.
 
 **Vector Length (vl)** <a name="vl" />
 
+The actual Vector length, the number of elements in a "Vector", vl may be set
+entirely dynamically at runtime from a number of sources. `setvl` is the primary
+instruction for setting Vector Length.
 `setvl` is conceptually similar but different from the Cray, SX Aurora, and RISC-V RVV
 equivalent. Similar to RVV, VL is set to be within
 the range 0 <= VL <= MVL. Unlike RVV, VL is set **exactly** according to the following:
 
     VL = (RT|0) = MIN(vlen, MVL)
 
-where 0 <= MVL <= XLEN and vlen may come from an immediate, `RA`, or from the `CTR` SPR,
-depending on options set with the `setvl` instruction.
+where 0 <= MVL <= 127 and vlen may come from an immediate, `RA`, or from the `CTR` SPR,
+depending on options selected with the `setvl` instruction.
+
+Programmer's Note: understanding of Cray-style Vectors is far beyond the scope
+of the Power ISA Technical Reference.  Guidance on the Cray Vector paradigm is
+best sought elsewhere: good studies include Academic Courses given on the 1970s
+Cray Supercomputers over the past 30 years.
 
 **SUBVL - Sub Vector Length**
 
@@ -303,6 +312,8 @@ representing 1 operation (1 element) thru 4 operations (4 elements) respectively
 Elements are best though of in the context of 3D, Audio and Video: two Left and Right
 Channel "elements" or four ARGB "elements", or three XYZ coordinate "elements".
 
+`subvl` is again primarily set by the `setvl` instruction.
+
 **Horizontal Parallelism**
 
 A problem exists for hardware where it may not be able to detect