From: lkcl <lkcl@web>
Date: Thu, 24 Dec 2020 23:56:37 +0000 (+0000)
Subject: (no commit message)
X-Git-Tag: convert-csv-opcode-to-binary~937
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1a400df811de378bb1159b1ad9d217a641ef9bd5;p=libreriscv.git

---

diff --git a/openpower/sv/overview.mdwn b/openpower/sv/overview.mdwn
index 029c86d8d..e13c58ced 100644
--- a/openpower/sv/overview.mdwn
+++ b/openpower/sv/overview.mdwn
@@ -218,14 +218,15 @@ Swizzle is particularly important for 3D work.  It allows in-place reordering of
 In SV given the percentage of operations that also involve initislisation to 0.0 or 1.0 into subvector elements the decision was made to include those:
 
     swizzle = get_swizzle_immed() # 12 bits
-    remap = (swizzle >> 3*s) & 0b111
-    if remap < 4:
-       sm = id*SUBVL + remap
-       ireg[rd+s] <= ireg[rs1+sm]
-    elif remap == 4:
-          ireg[rd+s] <= 0.0
-    elif remap == 5:
-          ireg[rd+s] <= 1.0
+    for (s = 0; s < SUBVL; s++)
+        remap = (swizzle >> 3*s) & 0b111
+        if remap < 4:
+           sm = id*SUBVL + remap
+           ireg[rd+s] <= ireg[rs1+sm]
+        elif remap == 4:
+              ireg[rd+s] <= 0.0
+        elif remap == 5:
+              ireg[rd+s] <= 1.0
 
 Note that a value of 6 (and 7) will leave the target subvector element untouched. This is equivalent to a predicate mask which is built-in, in immediate form, into the [[sv/mv.swizzle]] operation.  mv.swizzle is rare in that it is one of the few instructions needed to be added that are never going to be part of a Scalar ISA.  Even in High Performance Compute workloads it is unusual: it is only because SV is targetted at 3D and Video that it is being considered.