From 94597b6146f30f949f2c454f424082a2b0f55a0e Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 22 Jul 2019 17:02:56 -0700 Subject: [PATCH] decodetree: Allow !function with no input bits Call this form a "parameter", returning a value extracted from the DisasContext. Reviewed-by: Philippe Mathieu-Daude Signed-off-by: Richard Henderson --- docs/devel/decodetree.rst | 8 ++++- scripts/decodetree.py | 49 ++++++++++++++++++++++++------- tests/decode/err_field6.decode | 5 ++++ tests/decode/succ_function.decode | 6 ++++ 4 files changed, 56 insertions(+), 12 deletions(-) create mode 100644 tests/decode/err_field6.decode create mode 100644 tests/decode/succ_function.decode diff --git a/docs/devel/decodetree.rst b/docs/devel/decodetree.rst index 44ac621ea8..ce7f52308f 100644 --- a/docs/devel/decodetree.rst +++ b/docs/devel/decodetree.rst @@ -23,7 +23,7 @@ Fields Syntax:: - field_def := '%' identifier ( unnamed_field )+ ( !function=identifier )? + field_def := '%' identifier ( unnamed_field )* ( !function=identifier )? unnamed_field := number ':' ( 's' ) number For *unnamed_field*, the first number is the least-significant bit position @@ -34,6 +34,12 @@ 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. +One may use ``!function`` with zero ``unnamed_fields``. This case is called +a *parameter*, and the named function is only passed the ``DisasContext`` +and returns an integral value extracted from there. + +A field with no ``unnamed_fields`` and no ``!function`` is in error. + 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. diff --git a/scripts/decodetree.py b/scripts/decodetree.py index d7a59d63ac..f6f7368774 100755 --- a/scripts/decodetree.py +++ b/scripts/decodetree.py @@ -245,7 +245,7 @@ class ConstField: class FunctionField: - """Class representing a field passed through an expander""" + """Class representing a field passed through a function""" def __init__(self, func, base): self.mask = base.mask self.sign = base.sign @@ -266,6 +266,27 @@ class FunctionField: # end FunctionField +class ParameterField: + """Class representing a pseudo-field read from a function""" + def __init__(self, func): + self.mask = 0 + self.sign = 0 + self.func = func + + def __str__(self): + return self.func + + def str_extract(self): + return self.func + '(ctx)' + + def __eq__(self, other): + return self.func == other.func + + def __ne__(self, other): + return not self.__eq__(other) +# end ParameterField + + class Arguments: """Class representing the extracted fields of a format""" def __init__(self, nm, flds, extern): @@ -433,17 +454,23 @@ def parse_field(lineno, name, toks): if width > insnwidth: error(lineno, 'field too large') - if len(subs) == 1: - f = subs[0] + if len(subs) == 0: + if func: + f = ParameterField(func) + else: + error(lineno, 'field with no value') else: - mask = 0 - for s in subs: - if mask & s.mask: - error(lineno, 'field components overlap') - mask |= s.mask - f = MultiField(subs, mask) - if func: - f = FunctionField(func, f) + if len(subs) == 1: + f = subs[0] + else: + mask = 0 + for s in subs: + if mask & s.mask: + error(lineno, 'field components overlap') + mask |= s.mask + f = MultiField(subs, mask) + if func: + f = FunctionField(func, f) if name in fields: error(lineno, 'duplicate field', name) diff --git a/tests/decode/err_field6.decode b/tests/decode/err_field6.decode new file mode 100644 index 0000000000..a719884572 --- /dev/null +++ b/tests/decode/err_field6.decode @@ -0,0 +1,5 @@ +# This work is licensed under the terms of the GNU LGPL, version 2 or later. +# See the COPYING.LIB file in the top-level directory. + +# Diagnose no bits in field +%field diff --git a/tests/decode/succ_function.decode b/tests/decode/succ_function.decode new file mode 100644 index 0000000000..7751b1784e --- /dev/null +++ b/tests/decode/succ_function.decode @@ -0,0 +1,6 @@ +# This work is licensed under the terms of the GNU LGPL, version 2 or later. +# See the COPYING.LIB file in the top-level directory. + +# "Field" as parameter pulled from DisasContext. +%foo !function=foo +foo 00000000000000000000000000000000 %foo