VFMAB, VFMAT (BFloat16, by scalar)

The BFloat16 floating-point widening multiply-add long instruction widens the even-numbered (bottom) or odd-numbered (top) 16-bit elements in the first source vector, and an 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.

Unlike other BFloat16 multiplication instructions, this performs a fused multiply-add, without intermediate rounding that uses the Round to Nearest rounding mode and can generate a floating-point exception that causes cumulative exception bits in the FPSCR to be set.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) .

A1
(FEAT_AA32BF16)

if !IsFeatureImplemented(FEAT_AA32BF16) then UNDEFINED; if Vd<0> == '1' || Vn<0> == '1' then UNDEFINED; constant integer d = UInt(D:Vd); constant integer n = UInt(N:Vn); constant integer m = UInt(Vm<2:0>); constant integer i = UInt(M:Vm<3>); constant integer elements = 128 DIV 32; constant integer sel = UInt(Q);

T1
(FEAT_AA32BF16)

if InITBlock() then UNPREDICTABLE; if !IsFeatureImplemented(FEAT_AA32BF16) then UNDEFINED; if Vd<0> == '1' || Vn<0> == '1' then UNDEFINED; constant integer d = UInt(D:Vd); constant integer n = UInt(N:Vn); constant integer m = UInt(Vm<2:0>); constant integer i = UInt(M:Vm<3>); constant integer elements = 128 DIV 32; constant integer sel = UInt(Q);