LD1RSB
Load and broadcast signed byte to vector
Load a single signed byte from a memory address generated by a 64-bit scalar base address plus an immediate offset which is in the range 0 to 63.
Broadcast the loaded data into all active elements of the destination vector, setting the inactive elements to zero. If all elements are inactive then the instruction will not perform a read from Device memory or cause a data abort.
Green
True
True
True
It has encodings from 3 classes:
16-bit element
,
32-bit element
and
64-bit element
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LD1RSB { <Zt>.H }, <Pg>/Z, [<Xn|SP>{, #<imm>}]
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer g = UInt(Pg);
constant integer esize = 16;
constant integer msize = 8;
constant boolean unsigned = FALSE;
constant integer offset = UInt(imm6);
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LD1RSB { <Zt>.S }, <Pg>/Z, [<Xn|SP>{, #<imm>}]
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer g = UInt(Pg);
constant integer esize = 32;
constant integer msize = 8;
constant boolean unsigned = FALSE;
constant integer offset = UInt(imm6);
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LD1RSB { <Zt>.D }, <Pg>/Z, [<Xn|SP>{, #<imm>}]
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer g = UInt(Pg);
constant integer esize = 64;
constant integer msize = 8;
constant boolean unsigned = FALSE;
constant integer offset = UInt(imm6);
<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.
<imm>
Is the optional unsigned immediate byte offset, in the range 0 to 63, defaulting to 0, encoded in the "imm6" 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;
constant integer mbytes = msize DIV 8;
constant boolean contiguous = TRUE;
constant boolean nontemporal = FALSE;
constant boolean tagchecked = n != 31;
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];
constant bits(64) addr = AddressAdd(base, offset * mbytes, accdesc);
data = Mem[addr, mbytes, accdesc];
for e = 0 to elements-1
if ActivePredicateElement(mask, e, esize) then
Elem[result, e, esize] = Extend(data, esize, unsigned);
else
Elem[result, e, esize] = Zeros(esize);
Z[t, VL] = result;