diff options
Diffstat (limited to 'scripts')
| -rwxr-xr-x | scripts/decodetree.py | 333 |
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: -# -# ®3 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: |