SUB (array results, multiple and single vector)

Subtract replicated single vector from multi-vector with ZA array vector results

Subtract all corresponding elements of the second source vector from the two or four first source vectors and place the results in the corresponding elements of the ZA single-vector groups. The vector numbers forming the single-vector group within each half of or each quarter of the ZA array are selected by the sum of the vector select register and immediate 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 is unpredicated.

ID_AA64SMFR0_EL1.I16I64 indicates whether the 64-bit integer variant is implemented.

It has encodings from 2 classes: Two ZA single-vectors and Four ZA single-vectors

Two ZA single-vectors
(FEAT_SME2)

313029282726252423222120191817161514131211109876543210
110000010sz10Zm0Rv110Zn11off3
S

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

if !HaveSME2() then UNDEFINED; if sz == '1' && !HaveSMEI16I64() then UNDEFINED; integer v = UInt('010':Rv); constant integer esize = 32 << UInt(sz); integer n = UInt(Zn); integer m = UInt('0':Zm); integer offset = UInt(off3); constant integer nreg = 2;

Four ZA single-vectors
(FEAT_SME2)

313029282726252423222120191817161514131211109876543210
110000010sz11Zm0Rv110Zn11off3
S

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

if !HaveSME2() then UNDEFINED; if sz == '1' && !HaveSMEI16I64() then UNDEFINED; integer v = UInt('010':Rv); constant integer esize = 32 << UInt(sz); integer n = UInt(Zn); integer m = UInt('0':Zm); 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; integer vectors = VL DIV 8; integer vstride = vectors DIV nreg; bits(32) vbase = X[v, 32]; integer vec = (UInt(vbase) + offset) MOD vstride; bits(VL) result; for r = 0 to nreg-1 bits(VL) operand1 = Z[(n+r) MOD 32, VL]; bits(VL) operand2 = Z[m, VL]; for e = 0 to elements-1 bits(esize) element1 = Elem[operand1, e, esize]; bits(esize) element2 = Elem[operand2, e, esize]; Elem[result, e, esize] = element1 - element2; ZAvector[vec, VL] = result; vec = vec + vstride;

Operational information

If PSTATE.DIT is 1:


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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