From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 15 May 2023 19:16:15 +0000 (+0100)
Subject: fix empty slot in EXTRA
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d8713626ef4a4831f98394a47854148292635843;p=openpower-isa.git

fix empty slot in EXTRA
move (swap) Mode[0] and Mode[1] in CROps,
ff y/n is now Mode[1], VLI is now Mode[0].
https://bugs.libre-soc.org/show_bug.cgi?id=1083
---

diff --git a/src/openpower/consts.py b/src/openpower/consts.py
index 7dc9e4b2..9774eda3 100644
--- a/src/openpower/consts.py
+++ b/src/openpower/consts.py
@@ -263,7 +263,7 @@ class SVP64MODEb(_Const):
     INV = 2  # invert CR sense 0=set 1=unset
     CR_MSB = 3  # CR bit to update (with Rc=1)
     CR_LSB = 4
-    VLI = 3
+    VLI = 0
     RC1 = 4  # update CR as if Rc=1 (when Rc=0)
     # LD immediate els (element-stride) locations, depending on mode
     ELS_NORMAL = 4
diff --git a/src/openpower/decoder/power_enums.py b/src/openpower/decoder/power_enums.py
index 3bd7eee1..27f860b4 100644
--- a/src/openpower/decoder/power_enums.py
+++ b/src/openpower/decoder/power_enums.py
@@ -496,7 +496,6 @@ class SVP64RMMode(Enum):
     MAPREDUCE = 1
     FFIRST = 2
     SATURATE = 3
-    PREDRES = 4
     BRANCH = 5
 
 
diff --git a/src/openpower/decoder/power_insn.py b/src/openpower/decoder/power_insn.py
index 44888ea2..ab1ead61 100644
--- a/src/openpower/decoder/power_insn.py
+++ b/src/openpower/decoder/power_insn.py
@@ -1262,8 +1262,6 @@ class ExtendableOperand(DynamicOperand):
             that_extra_reg = pairs.get(extra_reg, extra_reg)
             if this_extra_reg is that_extra_reg:
                 bits = tuple(self.record.extra_idx(key=key, regtype=rtype))
-                if len(bits) == 0: # empty slot, do not attempt to use it!
-                    continue
                 if this_extra_reg in found:
                     assert found[this_extra_reg] == bits # check identical bits
                     continue                             # skip - already found
@@ -2587,7 +2585,7 @@ class SpecifierFF(SpecifierPredicate):
         if selector.mode.sel != 0:
             raise ValueError("cannot override mode")
         if self.record.svp64.mode is _SVMode.CROP:
-            selector.mode.sel = 0b10
+            selector.mode.sel = 0b01
             # HACK: please finally provide correct logic for CRs.
             if self.pred in (_SVP64Pred.RC1, _SVP64Pred.RC1_N):
                 selector.mode[2] = (self.pred is _SVP64Pred.RC1_N)
@@ -3315,8 +3313,8 @@ class RMSelector:
             table = (
                 (0b000000, 0b111000, "simple"), # simple
                 (0b001000, 0b111000, "mr"),     # mapreduce
-                (0b100001, 0b100001, "ff3"),    # ffirst, 3-bit CR
-                (0b100000, 0b100000, "ff5"),    # ffirst, 5-bit CR
+                (0b010001, 0b010001, "ff3"),    # ffirst, 3-bit CR
+                (0b010000, 0b010000, "ff5"),    # ffirst, 5-bit CR
             )
             search = ((int(self.insn.prefix.rm.crop.mode) << 1) |
                       int(self.record.svp64.extra_CR_3bit))
diff --git a/src/openpower/decoder/power_svp64_rm.py b/src/openpower/decoder/power_svp64_rm.py
index b88b9a38..cfc72c28 100644
--- a/src/openpower/decoder/power_svp64_rm.py
+++ b/src/openpower/decoder/power_svp64_rm.py
@@ -331,13 +331,10 @@ class SVP64RMModeDecode(Elaboratable):
                         comb += self.mode.eq(SVP64RMMode.MAPREDUCE)
                     with m.Else():
                         comb += self.mode.eq(SVP64RMMode.NORMAL)
-                with m.Case(1):
+                with m.Case(1,3):
                     comb += self.mode.eq(SVP64RMMode.FFIRST) # ffirst
                 with m.Case(2):
                     comb += self.mode.eq(SVP64RMMode.SATURATE) # saturate
-                with m.Case(3):
-                    # mode = 0b11: arithmetic predicate-result
-                    comb += self.mode.eq(SVP64RMMode.PREDRES) # pred result
 
             # extract "reverse gear" for mapreduce mode
             with m.If((~is_ldst) &                     # not for LD/ST