decodetree: Initial support for variable-length ISAs
Assuming that the ISA clearly describes how to determine the length of the instruction, and the ISA has a reasonable maximum instruction length, the input to the decoder can be right-justified in an appropriate insn word. This is not 100% convenient, as out-of-line %fields are numbered relative to the maximum instruction length, but this appears to still be usable. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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Richard Henderson
parent
a6ae23831b
commit
17560e9349
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@ -27,6 +27,7 @@ import getopt
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insnwidth = 32
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insnmask = 0xffffffff
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variablewidth = False
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fields = {}
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arguments = {}
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formats = {}
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@ -289,7 +290,7 @@ class Arguments:
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class General:
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"""Common code between instruction formats and instruction patterns"""
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def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds):
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def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds, w):
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self.name = name
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self.file = input_file
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self.lineno = lineno
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@ -299,6 +300,7 @@ class General:
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self.undefmask = udfm
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self.fieldmask = fldm
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self.fields = flds
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self.width = w
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def __str__(self):
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return self.name + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
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@ -352,7 +354,7 @@ class Pattern(General):
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class MultiPattern(General):
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"""Class representing an overlapping set of instruction patterns"""
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def __init__(self, lineno, pats, fixb, fixm, udfm):
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def __init__(self, lineno, pats, fixb, fixm, udfm, w):
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self.file = input_file
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self.lineno = lineno
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self.pats = pats
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@ -360,6 +362,7 @@ class MultiPattern(General):
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self.fixedbits = fixb
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self.fixedmask = fixm
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self.undefmask = udfm
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self.width = w
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def __str__(self):
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r = "{"
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@ -502,7 +505,7 @@ def infer_argument_set(flds):
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return arg
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def infer_format(arg, fieldmask, flds):
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def infer_format(arg, fieldmask, flds, width):
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global arguments
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global formats
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global decode_function
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@ -521,6 +524,8 @@ def infer_format(arg, fieldmask, flds):
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continue
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if fieldmask != fmt.fieldmask:
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continue
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if width != fmt.width:
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continue
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if not eq_fields_for_fmts(flds, fmt.fields):
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continue
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return (fmt, const_flds)
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@ -529,7 +534,7 @@ def infer_format(arg, fieldmask, flds):
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if not arg:
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arg = infer_argument_set(flds)
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fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds)
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fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds, width)
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formats[name] = fmt
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return (fmt, const_flds)
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@ -546,6 +551,7 @@ def parse_generic(lineno, is_format, name, toks):
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global re_ident
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global insnwidth
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global insnmask
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global variablewidth
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fixedmask = 0
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fixedbits = 0
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@ -633,8 +639,15 @@ def parse_generic(lineno, is_format, name, toks):
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error(lineno, 'invalid token "{0}"'.format(t))
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width += shift
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if variablewidth and width < insnwidth and width % 8 == 0:
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shift = insnwidth - width
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fixedbits <<= shift
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fixedmask <<= shift
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undefmask <<= shift
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undefmask |= (1 << shift) - 1
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# We should have filled in all of the bits of the instruction.
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if not (is_format and width == 0) and width != insnwidth:
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elif not (is_format and width == 0) and width != insnwidth:
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error(lineno, 'definition has {0} bits'.format(width))
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# Do not check for fields overlaping fields; one valid usage
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@ -660,7 +673,7 @@ def parse_generic(lineno, is_format, name, toks):
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if name in formats:
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error(lineno, 'duplicate format name', name)
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fmt = Format(name, lineno, arg, fixedbits, fixedmask,
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undefmask, fieldmask, flds)
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undefmask, fieldmask, flds, width)
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formats[name] = fmt
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else:
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# Patterns can reference a format ...
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@ -670,12 +683,14 @@ def parse_generic(lineno, is_format, name, toks):
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error(lineno, 'pattern specifies both format and argument set')
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if fixedmask & fmt.fixedmask:
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error(lineno, 'pattern fixed bits overlap format fixed bits')
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if width != fmt.width:
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error(lineno, 'pattern uses format of different width')
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fieldmask |= fmt.fieldmask
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fixedbits |= fmt.fixedbits
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fixedmask |= fmt.fixedmask
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undefmask |= fmt.undefmask
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else:
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(fmt, flds) = infer_format(arg, fieldmask, flds)
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(fmt, flds) = infer_format(arg, fieldmask, flds, width)
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arg = fmt.base
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for f in flds.keys():
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if f not in arg.fields:
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@ -687,7 +702,7 @@ def parse_generic(lineno, is_format, name, toks):
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if f not in flds.keys() and f not in fmt.fields.keys():
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error(lineno, 'field {0} not initialized'.format(f))
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pat = Pattern(name, lineno, fmt, fixedbits, fixedmask,
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undefmask, fieldmask, flds)
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undefmask, fieldmask, flds, width)
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patterns.append(pat)
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allpatterns.append(pat)
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@ -727,6 +742,13 @@ def build_multi_pattern(lineno, pats):
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if p.lineno < lineno:
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lineno = p.lineno
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width = None
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for p in pats:
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if width is None:
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width = p.width
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elif width != p.width:
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error(lineno, 'width mismatch in patterns within braces')
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repeat = True
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while repeat:
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if fixedmask == 0:
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@ -742,7 +764,7 @@ def build_multi_pattern(lineno, pats):
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else:
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repeat = False
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mp = MultiPattern(lineno, pats, fixedbits, fixedmask, undefmask)
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mp = MultiPattern(lineno, pats, fixedbits, fixedmask, undefmask, width)
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patterns.append(mp)
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# end build_multi_pattern
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@ -979,13 +1001,14 @@ def main():
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global insntype
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global insnmask
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global decode_function
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global variablewidth
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decode_scope = 'static '
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long_opts = ['decode=', 'translate=', 'output=', 'insnwidth=',
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'static-decode=']
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'static-decode=', 'varinsnwidth=']
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try:
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(opts, args) = getopt.getopt(sys.argv[1:], 'o:w:', long_opts)
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(opts, args) = getopt.getopt(sys.argv[1:], 'o:vw:', long_opts)
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except getopt.GetoptError as err:
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error(0, err)
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for o, a in opts:
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@ -999,7 +1022,9 @@ def main():
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elif o == '--translate':
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translate_prefix = a
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translate_scope = ''
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elif o in ('-w', '--insnwidth'):
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elif o in ('-w', '--insnwidth', '--varinsnwidth'):
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if o == '--varinsnwidth':
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variablewidth = True
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insnwidth = int(a)
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if insnwidth == 16:
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insntype = 'uint16_t'
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