On 16/11/2015 16:16, Peter Maydell wrote: > Newer versions of clang warn: > > hw/audio/fmopl.c:1085:39: warning: shifting a negative signed value is > undefined [-Wshift-negative-value] > data = Limit( outd[0] , OPL_MAXOUT, OPL_MINOUT ); > ^~~~~~~~~~ > hw/audio/fmopl.c:75:28: note: expanded from macro 'OPL_MINOUT' > #define OPL_MINOUT (-0x8000<<OPL_OUTSB) > ~~~~~~~^ > > Rephrase the definition of OPL_MINOUT to avoid the undefined behaviour. > > Signed-off-by: Peter Maydell <[email protected]> > --- > hw/audio/fmopl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/audio/fmopl.c b/hw/audio/fmopl.c > index 81c0c1b..807b29c 100644 > --- a/hw/audio/fmopl.c > +++ b/hw/audio/fmopl.c > @@ -72,7 +72,7 @@ static int opl_dbg_maxchip,opl_dbg_chip; > /* final output shift , limit minimum and maximum */ > #define OPL_OUTSB (TL_BITS+3-16) /* OPL output final shift 16bit > */ > #define OPL_MAXOUT (0x7fff<<OPL_OUTSB) > -#define OPL_MINOUT (-0x8000<<OPL_OUTSB) > +#define OPL_MINOUT (-(0x8000<<OPL_OUTSB))
Again: let's stop this madness!!!!!!!!!!!!!!!!!!!!!! (Yes, so many exclamation marks). This is clearly computing -32768 * 2^N, not -(32768 * 2^N). The latter is totally, utterly wrong, because 32768 is _not even expressible_ as a 16-bit fixed point value, which OPL_MINOUT/OPL_MAXOUT obviously are. I'll shortly post a patch to disable this obnoxious warning. Paolo
