RSUBHNB
Rounding subtract narrow high part (bottom)
Subtract each vector element of the second source vector from the corresponding vector element in the first source vector, and place the most significant rounded half of the result in the even-numbered half-width destination elements, while setting the odd-numbered half-width destination elements to zero. This instruction is unpredicated.
Green
False
True
0
1
0
0
0
1
0
1
1
0
1
1
1
1
0
RSUBHNB <Zd>.<T>, <Zn>.<Tb>, <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
B
10
H
11
S
<Zn>
Is the name of the first source scalable vector register, encoded in the "Zn" field.
<Tb>
Is the size specifier,
size
<Tb>
00
RESERVED
01
H
10
S
11
D
<Zm>
Is the name of the second source scalable vector register, encoded in the "Zm" field.
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;
constant integer halfesize = esize DIV 2;
for e = 0 to elements-1
constant integer element1 = UInt(Elem[operand1, e, esize]);
constant integer element2 = UInt(Elem[operand2, e, esize]);
constant integer res = ((element1 - element2) + (1 << (halfesize - 1))) >> halfesize;
Elem[result, 2*e + 0, halfesize] = res<halfesize-1:0>;
Elem[result, 2*e + 1, halfesize] = Zeros(halfesize);
Z[d, VL] = result;