SUNPKHI, SUNPKLO

Signed unpack and extend half of vector

Unpack elements from the lowest or highest half of the source vector and then sign-extend them to place in elements of twice their size within the destination vector. This instruction is unpredicated.

Encoding: High half

Variants: FEAT_SVE || FEAT_SME (FEAT_SVE || FEAT_SME)

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	0	0	0	0	1	0	1			1	1	0	0	0	1	0	0	1	1	1	0
								size						U	H							Zn					Zd

SUNPKHI <Zd>.<T>, <Zn>.<Tb>

Decoding algorithm

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then
    EndOfDecode(Decode_UNDEF);
if size == '00' then EndOfDecode(Decode_UNDEF);
constant integer esize = 8 << UInt(size);
constant integer n = UInt(Zn);
constant integer d = UInt(Zd);
constant boolean unsigned = FALSE;
constant boolean hi = TRUE;

Encoding: Low half

Variants: FEAT_SVE || FEAT_SME (FEAT_SVE || FEAT_SME)

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	0	0	0	0	1	0	1			1	1	0	0	0	0	0	0	1	1	1	0
								size						U	H							Zn					Zd

SUNPKLO <Zd>.<T>, <Zn>.<Tb>

Decoding algorithm

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then
    EndOfDecode(Decode_UNDEF);
if size == '00' then EndOfDecode(Decode_UNDEF);
constant integer esize = 8 << UInt(size);
constant integer n = UInt(Zn);
constant integer d = UInt(Zd);
constant boolean unsigned = FALSE;
constant boolean hi = FALSE;

Operation

CheckSVEEnabled();
constant integer VL = CurrentVL;
constant integer elements = VL DIV esize;
constant integer hsize = esize DIV 2;
constant integer offset = if hi then elements else 0;
constant bits(VL) operand = Z[n, VL];
bits(VL) result;

for e = 0 to elements-1
    constant bits(hsize) element = Elem[operand, e + offset, hsize];
    Elem[result, e, esize] = Extend(element, esize, unsigned);

Z[d, VL] = result;

Explanations

<Zd>: Is the name of the destination scalable vector register, encoded in the "Zd" field.
<T>: <Zn>: Is the name of the source scalable vector register, encoded in the "Zn" field.
<Tb>:

Operational Notes

If PSTATE.DIT is 1:

• The execution time of this instruction is independent of:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.
• The response of this instruction to asynchronous exceptions does not vary based on:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.