FMLA (multiple and single vector)

Multi-vector floating-point fused multiply-add by vector

Multiply the corresponding floating-point elements of the two or four first source vector with corresponding elements of the second source vector and destructively add without intermediate rounding to the corresponding elements of the ZA single-vector groups.

The single-vector group within each half of or each quarter of the ZA array is selected by the sum of the vector select register and offset, modulo half or quarter the number of ZA array vectors.

The vector group symbol, VGx2 or VGx4, indicates that the ZA operand consists of two or four ZA single-vector groups respectively. The vector group symbol is preferred for disassembly, but optional in assembler source code.

This instruction follows SME ZA-targeting floating-point behaviors.

This instruction is unpredicated.

ID_AA64SMFR0_EL1.F64F64 indicates whether the double-precision variant is implemented, and ID_AA64SMFR0_EL1.F16F16 indicates whether the half-precision variant is implemented.

It has encodings from 4 classes: Two ZA single-vectors , Two ZA single-vectors of half precision elements , Four ZA single-vectors and Four ZA single-vectors of half precision elements

Two ZA single-vectors
(FEAT_SME2)

313029282726252423222120191817161514131211109876543210
110000010sz10Zm0Rv110Zn00off3
S

FMLA ZA.<T>[<Wv>, <offs>{, VGx2}], { <Zn1>.<T>-<Zn2>.<T> }, <Zm>.<T>

if !IsFeatureImplemented(FEAT_SME2) then UNDEFINED; if sz == '1' && !IsFeatureImplemented(FEAT_SME_F64F64) then UNDEFINED; constant integer v = UInt('010':Rv); constant integer esize = 32 << UInt(sz); constant integer n = UInt(Zn); constant integer m = UInt('0':Zm); constant integer offset = UInt(off3); constant integer nreg = 2;

Two ZA single-vectors of half precision elements
(FEAT_SME_F16F16)

313029282726252423222120191817161514131211109876543210
110000010010Zm0Rv111Zn00off3
szS

FMLA ZA.H[<Wv>, <offs>{, VGx2}], { <Zn1>.H-<Zn2>.H }, <Zm>.H

if !IsFeatureImplemented(FEAT_SME_F16F16) then UNDEFINED; constant integer v = UInt('010':Rv); constant integer esize = 16; constant integer n = UInt(Zn); constant integer m = UInt('0':Zm); constant integer offset = UInt(off3); constant integer nreg = 2;

Four ZA single-vectors
(FEAT_SME2)

313029282726252423222120191817161514131211109876543210
110000010sz11Zm0Rv110Zn00off3
S

FMLA ZA.<T>[<Wv>, <offs>{, VGx4}], { <Zn1>.<T>-<Zn4>.<T> }, <Zm>.<T>

if !IsFeatureImplemented(FEAT_SME2) then UNDEFINED; if sz == '1' && !IsFeatureImplemented(FEAT_SME_F64F64) then UNDEFINED; constant integer v = UInt('010':Rv); constant integer esize = 32 << UInt(sz); constant integer n = UInt(Zn); constant integer m = UInt('0':Zm); constant integer offset = UInt(off3); constant integer nreg = 4;

Four ZA single-vectors of half precision elements
(FEAT_SME_F16F16)

313029282726252423222120191817161514131211109876543210
110000010011Zm0Rv111Zn00off3
szS

FMLA ZA.H[<Wv>, <offs>{, VGx4}], { <Zn1>.H-<Zn4>.H }, <Zm>.H

if !IsFeatureImplemented(FEAT_SME_F16F16) then UNDEFINED; constant integer v = UInt('010':Rv); constant integer esize = 16; constant integer n = UInt(Zn); constant integer m = UInt('0':Zm); constant integer offset = UInt(off3); constant integer nreg = 4;

Assembler Symbols

<T>

Is the size specifier, encoded in sz:

sz <T>
0 S
1 D
<Wv>

Is the 32-bit name of the vector select register W8-W11, encoded in the "Rv" field.

<offs>

Is the vector select offset, in the range 0 to 7, encoded in the "off3" field.

<Zn1>

Is the name of the first scalable vector register of the first source multi-vector group, encoded as "Zn".

<Zn4>

Is the name of the fourth scalable vector register of the first source multi-vector group, encoded as "Zn" plus 3 modulo 32.

<Zn2>

Is the name of the second scalable vector register of the first source multi-vector group, encoded as "Zn" plus 1 modulo 32.

<Zm>

Is the name of the second source scalable vector register Z0-Z15, encoded in the "Zm" field.

Operation

CheckStreamingSVEAndZAEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV esize; constant integer vectors = VL DIV 8; constant integer vstride = vectors DIV nreg; constant bits(32) vbase = X[v, 32]; integer vec = (UInt(vbase) + offset) MOD vstride; bits(VL) result; for r = 0 to nreg-1 constant bits(VL) op1 = Z[(n+r) MOD 32, VL]; constant bits(VL) op2 = Z[m, VL]; constant bits(VL) op3 = ZAvector[vec, VL]; for e = 0 to elements-1 constant bits(esize) elem1 = Elem[op1, e, esize]; constant bits(esize) elem2 = Elem[op2, e, esize]; constant bits(esize) elem3 = Elem[op3, e, esize]; Elem[result, e, esize] = FPMulAdd_ZA(elem3, elem1, elem2, FPCR); ZAvector[vec, VL] = result; vec = vec + vstride;


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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