8-bit floating-point multiply-add to half-precision (vector)
This instruction widens the even-numbered (bottom) or odd-numbered (top) 8-bit elements in the first and second source vectors 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 source vectors.
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.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 0 | Q | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | Rm | 1 | 1 | 1 | 1 | 1 | 1 | Rn | Rd | ||||||||||||
| U | size | opcode | |||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_FP8FMA) then EndOfDecode(Decode_UNDEF); end; let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm); let elements : integer = 128 DIV 16; let sel : integer = UInt(Q);
| <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, encoded in the "Rm" field. |
CheckFPMREnabled(); AArch64_CheckFPAdvSIMDEnabled(); let operand1 : bits(128) = V{}(n); let operand2 : bits(128) = V{}(m); let operand3 : bits(128) = V{}(d); var result : bits(128); for e = 0 to elements-1 do let element1 : bits(8) = operand1[(2 * e + sel)*:8]; let element2 : bits(8) = operand2[(2 * e + sel)*:8]; let element3 : bits(16) = operand3[e*:16]; result[e*:16] = FP8MulAddFP{16}(element3, element1, element2, FPCR(), FPMR()); end; V{128}(d) = result;
2026-03_rel 2026-03-26 20:48:11
Copyright © 2010-2026 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.