ST1W (scalar plus vector)

Scatter store words from a vector (vector index)

Scatter store of words from the active elements of a vector register to the memory addresses generated by a 64-bit scalar base plus vector index. The index values are optionally first sign or zero-extended from 32 to 64 bits and then optionally multiplied by 4. Inactive elements are not written to memory.

It has encodings from 6 classes: 32-bit scaled offset , 32-bit unpacked scaled offset , 32-bit unpacked unscaled offset , 32-bit unscaled offset , 64-bit scaled offset and 64-bit unscaled offset

32-bit scaled offset

313029282726252423222120191817161514131211109876543210
11100101011Zm1xs0PgRnZt
msz<1>msz<0>

ST1W { <Zt>.S }, <Pg>, [<Xn|SP>, <Zm>.S, <mod> #2]

if !HaveSVE() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Zm); integer g = UInt(Pg); integer esize = 32; integer msize = 32; integer offs_size = 32; boolean offs_unsigned = xs == '0'; integer scale = 2;

32-bit unpacked scaled offset

313029282726252423222120191817161514131211109876543210
11100101001Zm1xs0PgRnZt
msz<1>msz<0>

ST1W { <Zt>.D }, <Pg>, [<Xn|SP>, <Zm>.D, <mod> #2]

if !HaveSVE() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Zm); integer g = UInt(Pg); integer esize = 64; integer msize = 32; integer offs_size = 32; boolean offs_unsigned = xs == '0'; integer scale = 2;

32-bit unpacked unscaled offset

313029282726252423222120191817161514131211109876543210
11100101000Zm1xs0PgRnZt
msz<1>msz<0>

ST1W { <Zt>.D }, <Pg>, [<Xn|SP>, <Zm>.D, <mod>]

if !HaveSVE() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Zm); integer g = UInt(Pg); integer esize = 64; integer msize = 32; integer offs_size = 32; boolean offs_unsigned = xs == '0'; integer scale = 0;

32-bit unscaled offset

313029282726252423222120191817161514131211109876543210
11100101010Zm1xs0PgRnZt
msz<1>msz<0>

ST1W { <Zt>.S }, <Pg>, [<Xn|SP>, <Zm>.S, <mod>]

if !HaveSVE() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Zm); integer g = UInt(Pg); integer esize = 32; integer msize = 32; integer offs_size = 32; boolean offs_unsigned = xs == '0'; integer scale = 0;

64-bit scaled offset

313029282726252423222120191817161514131211109876543210
11100101001Zm101PgRnZt
msz<1>msz<0>

ST1W { <Zt>.D }, <Pg>, [<Xn|SP>, <Zm>.D, LSL #2]

if !HaveSVE() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Zm); integer g = UInt(Pg); integer esize = 64; integer msize = 32; integer offs_size = 64; boolean offs_unsigned = TRUE; integer scale = 2;

64-bit unscaled offset

313029282726252423222120191817161514131211109876543210
11100101000Zm101PgRnZt
msz<1>msz<0>

ST1W { <Zt>.D }, <Pg>, [<Xn|SP>, <Zm>.D]

if !HaveSVE() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Zm); integer g = UInt(Pg); integer esize = 64; integer msize = 32; integer offs_size = 64; boolean offs_unsigned = TRUE; integer scale = 0;

Assembler Symbols

<Zt>

Is the name of the scalable vector register to be transferred, encoded in the "Zt" field.

<Pg>

Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field.

<Xn|SP>

Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.

<Zm>

Is the name of the offset scalable vector register, encoded in the "Zm" field.

<mod>

Is the index extend and shift specifier, encoded in xs:

xs <mod>
0 UXTW
1 SXTW

Operation

CheckNonStreamingSVEEnabled(); integer elements = VL DIV esize; bits(64) base; bits(PL) mask = P[g]; bits(VL) offset; bits(VL) src; constant integer mbytes = msize DIV 8; if HaveMTEExt() then SetTagCheckedInstruction(TRUE); if !AnyActiveElement(mask, esize) then if n == 31 && ConstrainUnpredictableBool(Unpredictable_CHECKSPNONEACTIVE) then CheckSPAlignment(); else if n == 31 then CheckSPAlignment(); base = if n == 31 then SP[] else X[n]; offset = Z[m]; src = Z[t]; for e = 0 to elements-1 if ElemP[mask, e, esize] == '1' then integer off = Int(Elem[offset, e, esize]<offs_size-1:0>, offs_unsigned); bits(64) addr = base + (off << scale); Mem[addr, mbytes, AccType_NORMAL] = Elem[src, e, esize]<msize-1:0>;


Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41

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