From b44b3449a08818f0eb25b93faaf535e9c9a85e50 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sat, 16 May 2020 13:15:02 -0700 Subject: decodetree: Allow group covering the entire insn space 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 Signed-off-by: Richard Henderson --- scripts/decodetree.py | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'scripts/decodetree.py') 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) -- cgit v1.2.3