On 8/18/19 8:39 AM, Richard Henderson wrote:
> Call this form a "parameter", returning a value extracted
> from the DisasContext.
>
> 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..31e2f04ecb 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 FunctionField
Nit: 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 00..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 00..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 %foo
>
Reviewed-by: Philippe Mathieu-Daude
