FLOGB

Floating-point base 2 logarithm as integer

This instruction returns the signed integer base 2 logarithm of each floating-point input element |x| after normalization.

This is the unbiased exponent of x used in the representation of the floating-point value, such that, for positive x, x = significand × 2^exponent.

The integer results are placed in elements of the destination vector which have the same width (esize) as the floating-point input elements:

• If x is normal, the result is the base 2 logarithm of x.
• If x is subnormal, the result corresponds to the normalized representation.
• If x is infinite, the result is 2^(esize-1)-1.
• If x is ±0.0 or NaN, the result is -2^(esize-1).

Inactive elements in the destination vector register remain unmodified.

if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; if size == '00' then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd);