Re: [Qemu-devel] [PATCH 01/67] decodetree: Allow !function with no input bits
On 7/29/19 6:43 AM, Peter Maydell wrote: > On Fri, 26 Jul 2019 at 18:50, Richard Henderson > wrote: >> >> With this, we can have the function return a value from the DisasContext. >> >> Signed-off-by: Richard Henderson >> --- >> 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 00..632a9de252 >> --- /dev/null >> +++ b/tests/decode/succ_function.decode >> @@ -0,0 +1,2 @@ >> +%foo !function=foo >> +foo %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 ? Ah good point. Should be 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 ? Right on both counts. Because of how the loop in MultiField is set up, x will always be given 0. I'll see about cleaning this up. In the meantime, fyi, this is used for setting the S bit for thumb1 insns, where S=0 iff the insn is within an IT block. r~
Re: [Qemu-devel] [PATCH 01/67] decodetree: Allow !function with no input bits
On Fri, 26 Jul 2019 at 18:50, Richard Henderson wrote: > > With this, we can have the function return a value from the DisasContext. > > Signed-off-by: Richard Henderson > --- > 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 00..632a9de252 > --- /dev/null > +++ b/tests/decode/succ_function.decode > @@ -0,0 +1,2 @@ > +%foo !function=foo > +foo %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
[Qemu-devel] [PATCH 01/67] decodetree: Allow !function with no input bits
With this, we can have the function return a value from the DisasContext. Signed-off-by: Richard Henderson --- 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 00..632a9de252 --- /dev/null +++ b/tests/decode/succ_function.decode @@ -0,0 +1,2 @@ +%foo !function=foo +foo %foo -- 2.17.1
