On Fri, 26 Jul 2019 at 18:50, Richard Henderson <richard.hender...@linaro.org> wrote: > > With this, we can have the function return a value from the DisasContext. > > Signed-off-by: Richard Henderson <richard.hender...@linaro.org> > --- > scripts/decodetree.py | 5 ++++- > tests/decode/succ_function.decode | 2 ++ > 2 files changed, 6 insertions(+), 1 deletion(-) > create mode 100644 tests/decode/succ_function.decode > > diff --git a/scripts/decodetree.py b/scripts/decodetree.py > index d7a59d63ac..4259d87a95 100755 > --- a/scripts/decodetree.py > +++ b/scripts/decodetree.py > @@ -195,7 +195,10 @@ class MultiField: > """Class representing a compound instruction field""" > def __init__(self, subs, mask): > self.subs = subs > - self.sign = subs[0].sign > + if len(subs): > + self.sign = subs[0].sign > + else: > + self.sign = 0 > self.mask = mask > > def __str__(self): > diff --git a/tests/decode/succ_function.decode > b/tests/decode/succ_function.decode > new file mode 100644 > index 0000000000..632a9de252 > --- /dev/null > +++ b/tests/decode/succ_function.decode > @@ -0,0 +1,2 @@ > +%foo !function=foo > +foo 00000000000000000000000000000000 %foo > -- > 2.17.1
Could you also update the documentation in docs/devel/decodetree.rst ? This code change looks like it also now allows definitions of fields that specify nothing at all (ie there's no check that a field definition with no "unnamed_field" parts has a !function specifier) -- what do they do, or should they be made syntax errors ? Is one of these functions which just returns a constant from no input bits still a "static int func(DisasContext *s, int x)" taking a pointless input argument, or is it now a "static int func(DisasContext *s)" ? I guess from the fact this code doesn't change the way a call is output that it is the former, but would the latter be cleaner ? (This would probably be implemented something like allowing FunctionField to be passed a base == None instead of allowing MultiFields with len(subs) == 0.) thanks -- PMM