add double-sld pseudocode, first draft

diff --git a/openpower/isa/svfixedarith.mdwn b/openpower/isa/svfixedarith.mdwn
index 7dfd4c551a82962f53446b678ac58d7b95970cbd..b44c4dba715ac65133d1966fb3283657c227c104 100644 (file)
--- a/openpower/isa/svfixedarith.mdwn
+++ b/openpower/isa/svfixedarith.mdwn
@@ -45,3 +45,26 @@ Pseudo-code:
 Special Registers Altered:
 
     None
+
+# [DRAFT] Twin (Quad) Left Shift Doubleword
+
+Z23-Form
+
+* dsld   RT,RA,RB,sm  (Rc=0)
+* dsld.   RT,RA,RB,sm  (Rc=1)
+
+Pseudo-code:
+
+    sh <- (RB)
+    src <- (RA) || (RT)
+    n <- sh[XLEN-7:XLEN-1]
+    r <- ROTL128(src, n)
+    if sh[XLEN-8] = 0 then
+         m <- MASK(0, XLEN*-1-n, XLEN*2)
+    else m <- [0]*XLEN*2
+    r <- r & m
+    RA <- r[XLEN:XLEN*2-1]
+
+Special Registers Altered:
+
+    CR0                    (if Rc=1)