LD1SB (scalar plus scalar)
Contiguous load signed bytes to vector (scalar index)
Contiguous load of signed bytes to elements of a vector register from the memory address generated by a 64-bit scalar base and scalar index which is added to the base address. After each element access the index value is incremented, but the index register is not updated. Inactive elements will not cause a read from Device memory or signal a fault, and are set to zero in the destination vector.
Green
True
True
True
It has encodings from 3 classes:
16-bit element
,
32-bit element
and
64-bit element
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0
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1
1
1
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0
LD1SB { <Zt>.H }, <Pg>/Z, [<Xn|SP>, <Xm>]
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
if Rm == '11111' then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer g = UInt(Pg);
constant integer esize = 16;
constant integer msize = 8;
constant boolean unsigned = FALSE;
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1
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LD1SB { <Zt>.S }, <Pg>/Z, [<Xn|SP>, <Xm>]
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
if Rm == '11111' then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer g = UInt(Pg);
constant integer esize = 32;
constant integer msize = 8;
constant boolean unsigned = FALSE;
1
0
1
0
0
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LD1SB { <Zt>.D }, <Pg>/Z, [<Xn|SP>, <Xm>]
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
if Rm == '11111' then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer g = UInt(Pg);
constant integer esize = 64;
constant integer msize = 8;
constant boolean unsigned = FALSE;
<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.
<Xm>
Is the 64-bit name of the general-purpose offset register, encoded in the "Rm" field.
CheckSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
constant integer elements = VL DIV esize;
bits(64) base;
constant bits(PL) mask = P[g, PL];
bits(VL) result;
bits(msize) data;
bits(64) offset;
bits(64) addr;
constant integer mbytes = msize DIV 8;
constant boolean contiguous = TRUE;
constant boolean nontemporal = FALSE;
constant boolean tagchecked = TRUE;
constant AccessDescriptor accdesc = CreateAccDescSVE(MemOp_LOAD, nontemporal, contiguous,
tagchecked);
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, 64];
offset = X[m, 64];
addr = AddressAdd(base, UInt(offset) * mbytes, accdesc);
for e = 0 to elements-1
if ActivePredicateElement(mask, e, esize) then
data = Mem[addr, mbytes, accdesc];
Elem[result, e, esize] = Extend(data, esize, unsigned);
else
Elem[result, e, esize] = Zeros(esize);
addr = AddressIncrement(addr, mbytes, accdesc);
Z[t, VL] = result;