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[PULL 4/9] decodetree: Allow group covering the entire insn space
From: |
Richard Henderson |
Subject: |
[PULL 4/9] decodetree: Allow group covering the entire insn space |
Date: |
Tue, 9 Jun 2020 09:24:59 -0700 |
This is an edge case for sure, but the logic that disallowed
this case was faulty. Further, a few fixes scattered about
can allow this to work.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
...est1.decode => succ_pattern_group_nest2.decode} | 2 +-
scripts/decodetree.py | 14 +++++++++++---
2 files changed, 12 insertions(+), 4 deletions(-)
rename tests/decode/{err_pattern_group_nest1.decode =>
succ_pattern_group_nest2.decode} (85%)
diff --git a/tests/decode/err_pattern_group_nest1.decode
b/tests/decode/succ_pattern_group_nest2.decode
similarity index 85%
rename from tests/decode/err_pattern_group_nest1.decode
rename to tests/decode/succ_pattern_group_nest2.decode
index 92e971c3c5..8d5ab4b2d3 100644
--- a/tests/decode/err_pattern_group_nest1.decode
+++ b/tests/decode/succ_pattern_group_nest2.decode
@@ -6,7 +6,7 @@
%sub3 16:8
%sub4 24:8
-# Groups with no overlap are supposed to fail
+# Group with complete overlap of the two patterns
{
top 00000000 00000000 00000000 00000000
sub4 ........ ........ ........ ........ %sub1 %sub2 %sub3 %sub4
diff --git a/scripts/decodetree.py b/scripts/decodetree.py
index ea313bcdea..3307c74c30 100755
--- a/scripts/decodetree.py
+++ b/scripts/decodetree.py
@@ -124,6 +124,7 @@ def is_pow2(x):
def ctz(x):
"""Return the number of times 2 factors into X."""
+ assert x != 0
r = 0
while ((x >> r) & 1) == 0:
r += 1
@@ -131,6 +132,8 @@ def ctz(x):
def is_contiguous(bits):
+ if bits == 0:
+ return -1
shift = ctz(bits)
if is_pow2((bits >> shift) + 1):
return shift
@@ -793,9 +796,8 @@ def build_incmulti_pattern(lineno, pats):
error(lineno, 'width mismatch in patterns within braces')
repeat = True
- while repeat:
- if fixedmask == 0:
- error(lineno, 'no overlap in patterns within braces')
+ fixedbits = 0
+ while repeat and fixedmask != 0:
fixedbits = None
for p in pats:
thisbits = p.fixedbits & fixedmask
@@ -978,6 +980,12 @@ def build_tree(pats, outerbits, outermask):
innermask &= i.fixedmask
if innermask == 0:
+ # Edge condition: One pattern covers the entire insnmask
+ if len(pats) == 1:
+ t = Tree(outermask, innermask)
+ t.subs.append((0, pats[0]))
+ return t
+
text = 'overlapping patterns:'
for p in pats:
text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)
--
2.25.1
- [PULL 0/9] decodetree: Add non-overlapping groups, Richard Henderson, 2020/06/09
- [PULL 2/9] decodetree: Rename MultiPattern to IncMultiPattern, Richard Henderson, 2020/06/09
- [PULL 1/9] decodetree: Tidy error_with_file, Richard Henderson, 2020/06/09
- [PULL 3/9] decodetree: Split out MultiPattern from IncMultiPattern, Richard Henderson, 2020/06/09
- [PULL 4/9] decodetree: Allow group covering the entire insn space,
Richard Henderson <=
- [PULL 6/9] decodetree: Implement non-overlapping groups, Richard Henderson, 2020/06/09
- [PULL 5/9] decodetree: Move semantic propagation into classes, Richard Henderson, 2020/06/09
- [PULL 8/9] decodetree: Drop check for less than 2 patterns in a group, Richard Henderson, 2020/06/09
- [PULL 7/9] tests/decode: Test non-overlapping groups, Richard Henderson, 2020/06/09
- [PULL 9/9] target/arm: Use a non-overlapping group for misc control, Richard Henderson, 2020/06/09
- Re: [PULL 0/9] decodetree: Add non-overlapping groups, Peter Maydell, 2020/06/11