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RSUBHNT

Rounding subtract narrow high part (top).

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 odd-numbered half-width destination elements, leaving the even-numbered elements unchanged. This instruction is unpredicated.

313029282726252423222120191817161514131211109876543210
01000101size1Zm011111ZnZd

SVE2

RSUBHNT <Zd>.<T>, <Zn>.<Tb>, <Zm>.<Tb>

if !HaveSVE2() then UNDEFINED;
if size == '00' then UNDEFINED;
integer esize = 8 << UInt(size);
integer n = UInt(Zn);
integer m = UInt(Zm);
integer d = UInt(Zd);

Assembler Symbols

<Zd>

Is the name of the destination scalable vector register, encoded in the "Zd" field.

<T> Is the size specifier, encoded in size:
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, encoded in size:
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.

Operation

CheckSVEEnabled();
integer elements = VL DIV esize;
bits(VL) operand1 = Z[n];
bits(VL) operand2 = Z[m];
bits(VL) result = Z[d];
integer halfesize = esize DIV 2;
integer round_const = 1 << (halfesize - 1);

for e = 0 to elements-1
    integer element1 = UInt(Elem[operand1, e, esize]);
    integer element2 = UInt(Elem[operand2, e, esize]);
    integer res = ((element1 - element2) + round_const) >> halfesize;
    Elem[result, 2*e + 1, halfesize] = res<halfesize-1:0>;

Z[d] = result;