[AMD Official Use Only] Thanks for the information. I will use 0xffffffffu then. BR Evan > -----Original Message----- > From: Lazar, Lijo <Lijo.Lazar@xxxxxxx> > Sent: Tuesday, June 22, 2021 6:40 PM > To: Michel Dänzer <michel@xxxxxxxxxxx>; Quan, Evan > <Evan.Quan@xxxxxxx> > Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; amd- > gfx@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH V3 1/7] drm/amdgpu: correct tcp harvest setting > > > > On 6/22/2021 2:49 PM, Michel Dänzer wrote: > > On 2021-06-22 8:08 a.m., Lazar, Lijo wrote: > >> [Public] > >> > >> AFAIK, that expression is legal (some code analyzer may warn on value of > 4*max_wgp_per_sh); similar kind is used in rotate shift operations. > > > > The default type for constants in C is int, so 0xffffffff is a 32-bit signed > integer. > > Probably not as per section 6.4.4. > > "The type of an integer constant is the first of the corresponding list in which > its value can be represented." > > It is a hexadecimal constant and the first to fit this value is unsigned int. > Regardless, adding u suffix will avoid any ambiguity. > > Thanks, > Lijo > > > > > The C99 specification lists this under J.2 Undefined behavior: > > > > — An expression having signed promoted type is left-shifted and either > the value of the > > expression is negative or the result of shifting would be not be > representable in the > > promoted type (6.5.7). > > > > So it would be safer to make it unsigned: 0xffffffffu (or just ~0u). > > > > > >> -----Original Message----- > >> From: Quan, Evan <Evan.Quan@xxxxxxx> > >> Sent: Tuesday, June 22, 2021 7:56 AM > >> To: Lazar, Lijo <Lijo.Lazar@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx > >> Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx> > >> Subject: RE: [PATCH V3 1/7] drm/amdgpu: correct tcp harvest setting > >> > >> [AMD Official Use Only] > >> > >> Thanks Lijo. > >> However, I'm not quite sure whether " 0xffffffff << (4 * > max_wgp_per_sh);" is a valid expression since it kind of triggers some > overflow. > >> Can that work for non-x86 platform or even work reliably for x86 platform? > > > > > > _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
