FMLALB, FMLALT (by element)

8-bit floating-point multiply-add long to half-precision (vector, by element). This instruction widens the even-numbered (bottom) or odd-numbered (top) 8-bit elements in the first source vector and the indexed element from the second source vector to half-precision format and multiplies the corresponding elements. The intermediate products are scaled by 2-UInt(FPMR.LSCALE[3:0]), before being destructively added without intermediate rounding to the half-precision elements of the destination vector that overlap with the corresponding 8-bit floating-point elements in the first source vector.

The 8-bit floating-point encoding format for the elements of the first source vector is selected by FPMR.F8S1. The 8-bit floating-point encoding format for the elements of the second source vector is selected by FPMR.F8S2.

Advanced SIMD
(FEAT_FP8FMA)

313029282726252423222120191817161514131211109876543210
0Q00111111LMRm0000H0RnRd
Usizeopcode

FMLALB (Q == 0)

FMLALB <Vd>.8H, <Vn>.16B, <Vm>.B[<index>]

FMLALT (Q == 1)

FMLALT <Vd>.8H, <Vn>.16B, <Vm>.B[<index>]

if !IsFeatureImplemented(FEAT_FP8FMA) then UNDEFINED; integer n = UInt(Rn); integer m = UInt('00':Rm<2:0>); integer d = UInt(Rd); integer index = UInt(H:L:M:Rm<3>); constant integer elements = 128 DIV 16; integer sel = UInt(Q);

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<Vn>

Is the name of the first SIMD&FP source register, encoded in the "Rn" field.

<Vm>

Is the name of the second SIMD&FP source register, in the range V0 to V7, encoded in the "Rm<2:0>" field.

<index>

Is the element index, in the range 0 to 15, encoded in the "H:L:M:Rm<3>" fields.

Operation

CheckFPMREnabled(); CheckFPAdvSIMDEnabled64(); bits(128) operand1 = V[n, 128]; bits(128) operand2 = V[m, 128]; bits(128) operand3 = V[d, 128]; bits(128) result; for e = 0 to elements-1 bits(8) element1 = Elem[operand1, 2*e+sel, 8]; bits(8) element2 = Elem[operand2, index, 8]; bits(16) element3 = Elem[operand3, e, 16]; Elem[result, e, 16] = FP8MulAddFP(element3, element1, element2, FPCR, FPMR); V[d, 128] = result;


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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