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-rwxr-xr-xscripts/decodetree.py333
1 files changed, 165 insertions, 168 deletions
diff --git a/scripts/decodetree.py b/scripts/decodetree.py
index e342d278b8..aa790b596a 100755
--- a/scripts/decodetree.py
+++ b/scripts/decodetree.py
@@ -17,139 +17,7 @@
#
# Generate a decoding tree from a specification file.
-#
-# The tree is built from instruction "patterns". A pattern may represent
-# a single architectural instruction or a group of same, depending on what
-# is convenient for further processing.
-#
-# Each pattern has "fixedbits" & "fixedmask", the combination of which
-# describes the condition under which the pattern is matched:
-#
-# (insn & fixedmask) == fixedbits
-#
-# Each pattern may have "fields", which are extracted from the insn and
-# passed along to the translator. Examples of such are registers,
-# immediates, and sub-opcodes.
-#
-# In support of patterns, one may declare fields, argument sets, and
-# formats, each of which may be re-used to simplify further definitions.
-#
-# *** Field syntax:
-#
-# field_def := '%' identifier ( unnamed_field )+ ( !function=identifier )?
-# unnamed_field := number ':' ( 's' ) number
-#
-# For unnamed_field, the first number is the least-significant bit position of
-# the field and the second number is the length of the field. If the 's' is
-# present, the field is considered signed. If multiple unnamed_fields are
-# present, they are concatenated. In this way one can define disjoint fields.
-#
-# If !function is specified, the concatenated result is passed through the
-# named function, taking and returning an integral value.
-#
-# FIXME: the fields of the structure into which this result will be stored
-# is restricted to "int". Which means that we cannot expand 64-bit items.
-#
-# Field examples:
-#
-# %disp 0:s16 -- sextract(i, 0, 16)
-# %imm9 16:6 10:3 -- extract(i, 16, 6) << 3 | extract(i, 10, 3)
-# %disp12 0:s1 1:1 2:10 -- sextract(i, 0, 1) << 11
-# | extract(i, 1, 1) << 10
-# | extract(i, 2, 10)
-# %shimm8 5:s8 13:1 !function=expand_shimm8
-# -- expand_shimm8(sextract(i, 5, 8) << 1
-# | extract(i, 13, 1))
-#
-# *** Argument set syntax:
-#
-# args_def := '&' identifier ( args_elt )+ ( !extern )?
-# args_elt := identifier
-#
-# Each args_elt defines an argument within the argument set.
-# Each argument set will be rendered as a C structure "arg_$name"
-# with each of the fields being one of the member arguments.
-#
-# If !extern is specified, the backing structure is assumed to
-# have been already declared, typically via a second decoder.
-#
-# Argument set examples:
-#
-# &reg3 ra rb rc
-# &loadstore reg base offset
-#
-# *** Format syntax:
-#
-# fmt_def := '@' identifier ( fmt_elt )+
-# fmt_elt := fixedbit_elt | field_elt | field_ref | args_ref
-# fixedbit_elt := [01.-]+
-# field_elt := identifier ':' 's'? number
-# field_ref := '%' identifier | identifier '=' '%' identifier
-# args_ref := '&' identifier
-#
-# Defining a format is a handy way to avoid replicating groups of fields
-# across many instruction patterns.
-#
-# A fixedbit_elt describes a contiguous sequence of bits that must
-# be 1, 0, [.-] for don't care. The difference between '.' and '-'
-# is that '.' means that the bit will be covered with a field or a
-# final [01] from the pattern, and '-' means that the bit is really
-# ignored by the cpu and will not be specified.
-#
-# A field_elt describes a simple field only given a width; the position of
-# the field is implied by its position with respect to other fixedbit_elt
-# and field_elt.
-#
-# If any fixedbit_elt or field_elt appear then all bits must be defined.
-# Padding with a fixedbit_elt of all '.' is an easy way to accomplish that.
-#
-# A field_ref incorporates a field by reference. This is the only way to
-# add a complex field to a format. A field may be renamed in the process
-# via assignment to another identifier. This is intended to allow the
-# same argument set be used with disjoint named fields.
-#
-# A single args_ref may specify an argument set to use for the format.
-# The set of fields in the format must be a subset of the arguments in
-# the argument set. If an argument set is not specified, one will be
-# inferred from the set of fields.
-#
-# It is recommended, but not required, that all field_ref and args_ref
-# appear at the end of the line, not interleaving with fixedbit_elf or
-# field_elt.
-#
-# Format examples:
-#
-# @opr ...... ra:5 rb:5 ... 0 ....... rc:5
-# @opi ...... ra:5 lit:8 1 ....... rc:5
-#
-# *** Pattern syntax:
-#
-# pat_def := identifier ( pat_elt )+
-# pat_elt := fixedbit_elt | field_elt | field_ref
-# | args_ref | fmt_ref | const_elt
-# fmt_ref := '@' identifier
-# const_elt := identifier '=' number
-#
-# The fixedbit_elt and field_elt specifiers are unchanged from formats.
-# A pattern that does not specify a named format will have one inferred
-# from a referenced argument set (if present) and the set of fields.
-#
-# A const_elt allows a argument to be set to a constant value. This may
-# come in handy when fields overlap between patterns and one has to
-# include the values in the fixedbit_elt instead.
-#
-# The decoder will call a translator function for each pattern matched.
-#
-# Pattern examples:
-#
-# addl_r 010000 ..... ..... .... 0000000 ..... @opr
-# addl_i 010000 ..... ..... .... 0000000 ..... @opi
-#
-# which will, in part, invoke
-#
-# trans_addl_r(ctx, &arg_opr, insn)
-# and
-# trans_addl_i(ctx, &arg_opi, insn)
+# See the syntax and semantics in docs/devel/decodetree.rst.
#
import os
@@ -163,6 +31,7 @@ fields = {}
arguments = {}
formats = {}
patterns = []
+allpatterns = []
translate_prefix = 'trans'
translate_scope = 'static '
@@ -432,13 +301,7 @@ class General:
self.fields = flds
def __str__(self):
- r = self.name
- if self.base:
- r = r + ' ' + self.base.name
- else:
- r = r + ' ' + str(self.fields)
- r = r + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
- return r
+ return self.name + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
def str1(self, i):
return str_indent(i) + self.__str__()
@@ -449,7 +312,8 @@ class Format(General):
"""Class representing an instruction format"""
def extract_name(self):
- return 'extract_' + self.name
+ global decode_function
+ return decode_function + '_extract_' + self.name
def output_extract(self):
output('static void ', self.extract_name(), '(',
@@ -480,11 +344,52 @@ class Pattern(General):
output(ind, self.base.extract_name(), '(&u.f_', arg, ', insn);\n')
for n, f in self.fields.items():
output(ind, 'u.f_', arg, '.', n, ' = ', f.str_extract(), ';\n')
- output(ind, 'return ', translate_prefix, '_', self.name,
- '(ctx, &u.f_', arg, ');\n')
+ output(ind, 'if (', translate_prefix, '_', self.name,
+ '(ctx, &u.f_', arg, ')) return true;\n')
# end Pattern
+class MultiPattern(General):
+ """Class representing an overlapping set of instruction patterns"""
+
+ def __init__(self, lineno, pats, fixb, fixm, udfm):
+ self.file = input_file
+ self.lineno = lineno
+ self.pats = pats
+ self.base = None
+ self.fixedbits = fixb
+ self.fixedmask = fixm
+ self.undefmask = udfm
+
+ def __str__(self):
+ r = "{"
+ for p in self.pats:
+ r = r + ' ' + str(p)
+ return r + "}"
+
+ def output_decl(self):
+ for p in self.pats:
+ p.output_decl()
+
+ def output_code(self, i, extracted, outerbits, outermask):
+ global translate_prefix
+ ind = str_indent(i)
+ for p in self.pats:
+ if outermask != p.fixedmask:
+ innermask = p.fixedmask & ~outermask
+ innerbits = p.fixedbits & ~outermask
+ output(ind, 'if ((insn & ',
+ '0x{0:08x}) == 0x{1:08x}'.format(innermask, innerbits),
+ ') {\n')
+ output(ind, ' /* ',
+ str_match_bits(p.fixedbits, p.fixedmask), ' */\n')
+ p.output_code(i + 4, extracted, p.fixedbits, p.fixedmask)
+ output(ind, '}\n')
+ else:
+ p.output_code(i, extracted, p.fixedbits, p.fixedmask)
+#end MultiPattern
+
+
def parse_field(lineno, name, toks):
"""Parse one instruction field from TOKS at LINENO"""
global fields
@@ -637,6 +542,7 @@ def parse_generic(lineno, is_format, name, toks):
global arguments
global formats
global patterns
+ global allpatterns
global re_ident
global insnwidth
global insnmask
@@ -684,7 +590,7 @@ def parse_generic(lineno, is_format, name, toks):
continue
# 'Foo=number' sets an argument field to a constant value
- if re_fullmatch(re_ident + '=[0-9]+', t):
+ if re_fullmatch(re_ident + '=[+-]?[0-9]+', t):
(fname, value) = t.split('=')
value = int(value)
flds = add_field(lineno, flds, fname, ConstField(value))
@@ -716,6 +622,8 @@ def parse_generic(lineno, is_format, name, toks):
sign = True
flen = flen[1:]
shift = int(flen, 10)
+ if shift + width > insnwidth:
+ error(lineno, 'field {0} exceeds insnwidth'.format(fname))
f = Field(sign, insnwidth - width - shift, shift)
flds = add_field(lineno, flds, fname, f)
fixedbits <<= shift
@@ -781,6 +689,7 @@ def parse_generic(lineno, is_format, name, toks):
pat = Pattern(name, lineno, fmt, fixedbits, fixedmask,
undefmask, fieldmask, flds)
patterns.append(pat)
+ allpatterns.append(pat)
# Validate the masks that we have assembled.
if fieldmask & fixedmask:
@@ -799,17 +708,66 @@ def parse_generic(lineno, is_format, name, toks):
.format(allbits ^ insnmask))
# end parse_general
+def build_multi_pattern(lineno, pats):
+ """Validate the Patterns going into a MultiPattern."""
+ global patterns
+ global insnmask
+
+ if len(pats) < 2:
+ error(lineno, 'less than two patterns within braces')
+
+ fixedmask = insnmask
+ undefmask = insnmask
+
+ # Collect fixed/undefmask for all of the children.
+ # Move the defining lineno back to that of the first child.
+ for p in pats:
+ fixedmask &= p.fixedmask
+ undefmask &= p.undefmask
+ if p.lineno < lineno:
+ lineno = p.lineno
+
+ repeat = True
+ while repeat:
+ if fixedmask == 0:
+ error(lineno, 'no overlap in patterns within braces')
+ fixedbits = None
+ for p in pats:
+ thisbits = p.fixedbits & fixedmask
+ if fixedbits is None:
+ fixedbits = thisbits
+ elif fixedbits != thisbits:
+ fixedmask &= ~(fixedbits ^ thisbits)
+ break
+ else:
+ repeat = False
+
+ mp = MultiPattern(lineno, pats, fixedbits, fixedmask, undefmask)
+ patterns.append(mp)
+# end build_multi_pattern
def parse_file(f):
"""Parse all of the patterns within a file"""
+ global patterns
+
# Read all of the lines of the file. Concatenate lines
# ending in backslash; discard empty lines and comments.
toks = []
lineno = 0
+ nesting = 0
+ saved_pats = []
+
for line in f:
lineno += 1
+ # Expand and strip spaces, to find indent.
+ line = line.rstrip()
+ line = line.expandtabs()
+ len1 = len(line)
+ line = line.lstrip()
+ len2 = len(line)
+
# Discard comments
end = line.find('#')
if end >= 0:
@@ -819,10 +777,18 @@ def parse_file(f):
if len(toks) != 0:
# Next line after continuation
toks.extend(t)
- elif len(t) == 0:
- # Empty line
- continue
else:
+ # Allow completely blank lines.
+ if len1 == 0:
+ continue
+ indent = len1 - len2
+ # Empty line due to comment.
+ if len(t) == 0:
+ # Indentation must be correct, even for comment lines.
+ if indent != nesting:
+ error(lineno, 'indentation ', indent, ' != ', nesting)
+ continue
+ start_lineno = lineno
toks = t
# Continuation?
@@ -830,21 +796,47 @@ def parse_file(f):
toks.pop()
continue
- if len(toks) < 2:
- error(lineno, 'short line')
-
name = toks[0]
del toks[0]
+ # End nesting?
+ if name == '}':
+ if nesting == 0:
+ error(start_lineno, 'mismatched close brace')
+ if len(toks) != 0:
+ error(start_lineno, 'extra tokens after close brace')
+ nesting -= 2
+ if indent != nesting:
+ error(start_lineno, 'indentation ', indent, ' != ', nesting)
+ pats = patterns
+ patterns = saved_pats.pop()
+ build_multi_pattern(lineno, pats)
+ toks = []
+ continue
+
+ # Everything else should have current indentation.
+ if indent != nesting:
+ error(start_lineno, 'indentation ', indent, ' != ', nesting)
+
+ # Start nesting?
+ if name == '{':
+ if len(toks) != 0:
+ error(start_lineno, 'extra tokens after open brace')
+ saved_pats.append(patterns)
+ patterns = []
+ nesting += 2
+ toks = []
+ continue
+
# Determine the type of object needing to be parsed.
if name[0] == '%':
- parse_field(lineno, name[1:], toks)
+ parse_field(start_lineno, name[1:], toks)
elif name[0] == '&':
- parse_arguments(lineno, name[1:], toks)
+ parse_arguments(start_lineno, name[1:], toks)
elif name[0] == '@':
- parse_generic(lineno, True, name[1:], toks)
+ parse_generic(start_lineno, True, name[1:], toks)
else:
- parse_generic(lineno, False, name, toks)
+ parse_generic(start_lineno, False, name, toks)
toks = []
# end parse_file
@@ -909,23 +901,22 @@ class Tree:
output(ind, ' /* ',
str_match_bits(innerbits, innermask), ' */\n')
s.output_code(i + 4, extracted, innerbits, innermask)
+ output(ind, ' return false;\n')
output(ind, '}\n')
- output(ind, 'return false;\n')
# end Tree
def build_tree(pats, outerbits, outermask):
# Find the intersection of all remaining fixedmask.
- innermask = ~outermask
+ innermask = ~outermask & insnmask
for i in pats:
innermask &= i.fixedmask
if innermask == 0:
- pnames = []
+ text = 'overlapping patterns:'
for p in pats:
- pnames.append(p.name + ':' + p.file + ':' + str(p.lineno))
- error_with_file(pats[0].file, pats[0].lineno,
- 'overlapping patterns:', pnames)
+ text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)
+ error_with_file(pats[0].file, pats[0].lineno, text)
fullmask = outermask | innermask
@@ -978,6 +969,7 @@ def main():
global arguments
global formats
global patterns
+ global allpatterns
global translate_scope
global translate_prefix
global output_fd
@@ -990,7 +982,8 @@ def main():
decode_scope = 'static '
- long_opts = ['decode=', 'translate=', 'output=', 'insnwidth=']
+ long_opts = ['decode=', 'translate=', 'output=', 'insnwidth=',
+ 'static-decode=']
try:
(opts, args) = getopt.getopt(sys.argv[1:], 'o:w:', long_opts)
except getopt.GetoptError as err:
@@ -1001,6 +994,8 @@ def main():
elif o == '--decode':
decode_function = a
decode_scope = ''
+ elif o == '--static-decode':
+ decode_function = a
elif o == '--translate':
translate_prefix = a
translate_scope = ''
@@ -1039,7 +1034,7 @@ def main():
# Make sure that the argument sets are the same, and declare the
# function only once.
out_pats = {}
- for i in patterns:
+ for i in allpatterns:
if i.name in out_pats:
p = out_pats[i.name]
if i.base.base != p.base.base:
@@ -1057,14 +1052,16 @@ def main():
'(DisasContext *ctx, ', insntype, ' insn)\n{\n')
i4 = str_indent(4)
- output(i4, 'union {\n')
- for n in sorted(arguments.keys()):
- f = arguments[n]
- output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
- output(i4, '} u;\n\n')
- t.output_code(4, False, 0, 0)
+ if len(allpatterns) != 0:
+ output(i4, 'union {\n')
+ for n in sorted(arguments.keys()):
+ f = arguments[n]
+ output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
+ output(i4, '} u;\n\n')
+ t.output_code(4, False, 0, 0)
+ output(i4, 'return false;\n')
output('}\n')
if output_file:
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-18 12:56:32 +0000