> > /** > > * @internal > > - * When 'x' is not already a power of two, round it up to the next > > - * power of two value. Zero is not supported as an input value. > > - */ > > -#define ODP_ROUNDUP_POWER_2(x)\ > > - (1 << (((int)(8 * sizeof(x))) - __builtin_clz((x) - 1))) > > + * Round up a uint32_t value 'x' to the next power of two. It's not > round up, > > + * if it's already a power of two. It must be larger than 0 and must > not exceed > > Macro fails and reports ODP_ROUNDUP_POWER_2(1) == 1 instead of the > correct answer 2. Probably easier to just document that arg must be > > 1 unless you want to special-case this endpoint.
Sent v2 which addresses this. Actually, 1 is also a power of two (2^0). > > > + * 0x80000000. > > + */ > > +#define _SHIFT_U32(x, y) (((uint32_t)(x)) >> (y)) > > +#define _POW2_U32_R1(x) (((uint32_t)(x)) | _SHIFT_U32(x, 1)) > > +#define _POW2_U32_R2(x) (_POW2_U32_R1(x) | > _SHIFT_U32(_POW2_U32_R1(x), 2)) > > +#define _POW2_U32_R3(x) (_POW2_U32_R2(x) | > _SHIFT_U32(_POW2_U32_R2(x), 4)) > > +#define _POW2_U32_R4(x) (_POW2_U32_R3(x) | > _SHIFT_U32(_POW2_U32_R3(x), 8)) > > +#define _POW2_U32_R5(x) (_POW2_U32_R4(x) | > _SHIFT_U32(_POW2_U32_R4(x), 16)) > > + > > +#define ODP_ROUNDUP_POWER2_U32(x) \ > > + (((x) > 0x80000000) ? 0 : (_POW2_U32_R5(x - 1) + 1)) > > Should be (((uint32_t)(x)) ... ) here otherwise fails if arg is not > unsigned. This is also in v2. -Petri
