Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

## FCVTN (FP16 to FP8)

Half-precision to 8-bit floating-point convert and narrow (vector). This instruction converts half-precision elements of the two source vectors to 8-bit floating-point while scaling the values by 2SInt(FPMR.NSCALE[4:0]), and places the in-order results in the 8-bit elements of the destination vector.

The 8-bit floating-point encoding format is selected by FPMR.F8D.

### Advanced SIMD
(FEAT_FP8)

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 | 0 | 1 | 0 | Rm | 1 | 1 | 1 | 1 | 0 | 1 | Rn | Rd

####

FCVTN <Vd>.<Ta>, <Vn>.<Tb>, <Vm>.<Tb>

if !IsFeatureImplemented(FEAT_FP8) then UNDEFINED; integer n = UInt(Rn); integer m = UInt(Rm); integer d = UInt(Rd); constant integer datasize = if Q == '1' then 128 else 64; constant integer elements = datasize DIV 16;

### Assembler Symbols

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

<Ta> | Is an arrangement specifier, encoded in Q:
Q | <Ta>
--- | ---
0 | 8B
1 | 16B

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

<Tb> | Is an arrangement specifier, encoded in Q:
Q | <Tb>
--- | ---
0 | 4H
1 | 8H

<Vm> | Is the name of the second SIMD&FP source register, encoded in the "Rm" field.

### Operation

CheckFPMREnabled(); CheckFPAdvSIMDEnabled64(); bits(datasize) operand1 = V[n, datasize]; bits(datasize) operand2 = V[m, datasize]; bits(datasize) result; for e = 0 to elements-1 Elem[result, 0*elements+e, 8] = FPConvertFP8(Elem[operand1, e, 16], FPCR, FPMR, 8); Elem[result, 1*elements+e, 8] = FPConvertFP8(Elem[operand2, e, 16], FPCR, FPMR, 8); V[d, datasize] = result;

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

Internal version only: isa v33.74, AdvSIMD v29.23, pseudocode v2023-09_rel, sve v2023-09_rc3 ; Build timestamp: 2023-09-27T17:06

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