BFMLALB, BFMLALT (by element)

BFloat16 floating-point widening multiply-add long (by element) widens the even-numbered (bottom) or odd-numbered (top) 16-bit elements in the first source vector, and the indexed element in the second source vector from Bfloat16 to single-precision format. The instruction then multiplies and adds these values to the overlapping single-precision elements of the destination vector.

This performs a fused multiply-add without intermediate rounding that honors all of the control bits in the FPCR that apply to single-precision arithmetic, including the rounding mode. It can also generate a floating-point exception that causes cumulative exception bits in the FPSR to be set, or a synchronous exception to be taken, depending on the enable bits in the FPCR. ID_AA64ISAR1_EL1.BF16 indicates whether this instruction is supported.

Vector
(FEAT_BF16)

if !HaveBF16Ext() then UNDEFINED; integer n = UInt(Rn); integer m = UInt('0':Rm); integer d = UInt(Rd); integer index = UInt(H:L:M); integer elements = 128 DIV 32; integer sel = UInt(Q);