[Libre-soc-bugs] [Bug 684] New: XLEN-16 fails when XLEN=8

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=684

            Bug ID: 684
           Summary: XLEN-16 fails when XLEN=8
           Product: Libre-SOC's first SoC
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: CONFIRMED
          Severity: enhancement
          Priority: ---
         Component: Source Code
          Assignee: lkcl at lkcl.net
          Reporter: lkcl at lkcl.net
                CC: libre-soc-bugs at lists.libre-soc.org
   NLnet milestone: ---

https://git.libre-soc.org/?p=openpower-isa.git;a=commitdiff;h=42e799cd6ed350b3bd3e6b84c97b9e09c76da0a1

-    if      a <u ([0]*48 || UI) then c <- 0b100
-    else if a >u ([0]*48 || UI) then c <- 0b010
+    if      a <u ([0]*(XLEN-16) || UI) then c <- 0b100
+    else if a >u ([0]*(XLEN-16) || UI) then c <- 0b010

this will go negative.  andi, ori and xori also have the same
issue

https://libre-soc.org/openpower/isa/fixedlogical/

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