From 063b0e181e8c25cc6493aa233d9f64f63bc3b629 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@cs.berkeley.edu>
Date: Wed, 31 Jul 2013 16:13:54 -0700
Subject: HW ignores upper bits of fence, but SW supplies 0

---
 instr-table.tex | 18 ++++++++++--------
 opcodes         |  8 ++++----
 parse-opcodes   | 24 ++++++++++++++----------
 3 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/instr-table.tex b/instr-table.tex
index f70e4a4..754816b 100644
--- a/instr-table.tex
+++ b/instr-table.tex
@@ -421,20 +421,22 @@
   
 
 &
-\multicolumn{1}{|c|}{rd} &
-\multicolumn{1}{c|}{rs1} &
-\multicolumn{5}{c|}{imm12} &
+\multicolumn{1}{|c|}{00000} &
+\multicolumn{1}{c|}{00000} &
+\multicolumn{1}{c|}{00000} &
+\multicolumn{4}{c|}{0000000} &
 \multicolumn{2}{c|}{001} &
-\multicolumn{1}{c|}{0101111} & FENCE.I rd,rs1,imm12 \\
+\multicolumn{1}{c|}{0101111} & FENCE.I  \\
 \cline{2-11}
   
 
 &
-\multicolumn{1}{|c|}{rd} &
-\multicolumn{1}{c|}{rs1} &
-\multicolumn{5}{c|}{imm12} &
+\multicolumn{1}{|c|}{00000} &
+\multicolumn{1}{c|}{00000} &
+\multicolumn{1}{c|}{00000} &
+\multicolumn{4}{c|}{0000000} &
 \multicolumn{2}{c|}{010} &
-\multicolumn{1}{c|}{0101111} & FENCE rd,rs1,imm12 \\
+\multicolumn{1}{c|}{0101111} & FENCE  \\
 \cline{2-11}
   
 
diff --git a/opcodes b/opcodes
index f5ba9f4..24c3f0a 100644
--- a/opcodes
+++ b/opcodes
@@ -108,10 +108,10 @@ lr.d rd rs1 21..17=0 16=1 15..10=0 9..7=3 6..2=0x0A 1..0=3
 sc.w rd rs1 rs2      16=1 15..10=1 9..7=2 6..2=0x0A 1..0=3
 sc.d rd rs1 rs2      16=1 15..10=1 9..7=3 6..2=0x0A 1..0=3
 
-fence.i     rd rs1 imm12 9..7=1 6..2=0x0B 1..0=3
-fence       rd rs1 imm12 9..7=2 6..2=0x0B 1..0=3
-fence.v.l   rd rs1 imm12 9..7=4 6..2=0x0B 1..0=3
-fence.v.g   rd rs1 imm12 9..7=5 6..2=0x0B 1..0=3
+fence.i     31..10=ignore 9..7=1 6..2=0x0B 1..0=3
+fence       31..10=ignore 9..7=2 6..2=0x0B 1..0=3
+fence.v.l   31..10=ignore 9..7=4 6..2=0x0B 1..0=3
+fence.v.g   31..10=ignore 9..7=5 6..2=0x0B 1..0=3
 
 syscall   31..27=0 26..22=0 21..17=0 16..10=0 9..7=0 6..2=0x1D 1..0=3
 break     31..27=0 26..22=0 21..17=0 16..10=0 9..7=1 6..2=0x1D 1..0=3
diff --git a/parse-opcodes b/parse-opcodes
index d918d40..fceefdb 100755
--- a/parse-opcodes
+++ b/parse-opcodes
@@ -526,29 +526,33 @@ for line in sys.stdin:
 
   for token in tokens[1:]:
     if len(token.split('=')) == 2:
-      tmp = token.split('=')
-      val = int(tmp[1],0)
-      if len(tmp[0].split('..')) == 2:
-        tmp = tmp[0].split('..')
+      tokens = token.split('=')
+      if len(tokens[0].split('..')) == 2:
+        tmp = tokens[0].split('..')
         hi = int(tmp[0])
         lo = int(tmp[1])
         if hi <= lo:
           sys.exit("%s: bad range %d..%d" % (name,hi,lo))
       else:
-        hi = lo = int(tmp[0])
-      if val >= (1 << (hi-lo+1)):
-        sys.exit("%s: bad value %d for range %d..%d" % (name,val,hi,lo))
-      mymatch = mymatch | (val << lo)
-      mymask = mymask | ((1<<(hi+1))-(1<<lo))
+        hi = lo = int(tokens[0])
+
+      if tokens[1] != 'ignore':
+        val = int(tokens[1], 0)
+        if val >= (1 << (hi-lo+1)):
+          sys.exit("%s: bad value %d for range %d..%d" % (name,val,hi,lo))
+        mymatch = mymatch | (val << lo)
+        mymask = mymask | ((1<<(hi+1))-(1<<lo))
+
       if cover & ((1<<(hi+1))-(1<<lo)):
         sys.exit("%s: overspecified" % name)
       cover = cover | ((1<<(hi+1))-(1<<lo))
+
     elif token in arglut:
       if cover & ((1<<(arglut[token][0]+1))-(1<<arglut[token][1])):
         sys.exit("%s: overspecified" % name)
       cover = cover | ((1<<(arglut[token][0]+1))-(1<<arglut[token][1]))
-
       arguments[name].append(token)
+
     else:
       sys.exit("%s: unknown token %s" % (name,token))
 
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