SSUBWT
Signed subtract wide (top)
Subtract the even-numbered signed elements of the second source vector from the overlapping double-width elements of the first source vector and place the results in the corresponding double-width elements of the destination vector. This instruction is unpredicated.
Green
False
True
0
1
0
0
0
1
0
1
0
0
1
0
1
0
1
SSUBWT <Zd>.<T>, <Zn>.<T>, <Zm>.<Tb>
if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
if size == '00' then UNDEFINED;
constant integer esize = 8 << UInt(size);
constant integer n = UInt(Zn);
constant integer m = UInt(Zm);
constant integer d = UInt(Zd);
<Zd>
Is the name of the destination scalable vector register, encoded in the "Zd" field.
<T>
Is the size specifier,
size
<T>
00
RESERVED
01
H
10
S
11
D
<Zn>
Is the name of the first source scalable vector register, encoded in the "Zn" field.
<Zm>
Is the name of the second source scalable vector register, encoded in the "Zm" field.
<Tb>
Is the size specifier,
size
<Tb>
00
RESERVED
01
B
10
H
11
S
CheckSVEEnabled();
constant integer VL = CurrentVL;
constant integer elements = VL DIV esize;
constant bits(VL) operand1 = Z[n, VL];
constant bits(VL) operand2 = Z[m, VL];
bits(VL) result;
for e = 0 to elements-1
constant integer element1 = SInt(Elem[operand1, e, esize]);
constant integer element2 = SInt(Elem[operand2, 2*e + 1, esize DIV 2]);
Elem[result, e, esize] = (element1 - element2)<esize-1:0>;
Z[d, VL] = result;