Rounding shift right narrow by immediate (bottom)
Shift each unsigned integer value in the source vector elements right by an immediate value, and place the rounded results in the even-numbered half-width destination elements, while setting the odd-numbered elements to zero. The immediate shift amount is an unsigned value in the range 1 to number of bits per element. This instruction is unpredicated.
| 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 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | tszh | 1 | tszl | imm3 | 0 | 0 | 0 | 1 | 1 | 0 | Zn | Zd | |||||||||||
| U | R | T | |||||||||||||||||||||||||||||
if !HaveSVE2() && !HaveSME() then UNDEFINED; bits(3) tsize = tszh:tszl; integer esize; case tsize of when '000' UNDEFINED; when '001' esize = 8; when '01x' esize = 16; when '1xx' esize = 32; integer n = UInt(Zn); integer d = UInt(Zd); integer shift = (2 * esize) - UInt(tsize:imm3);
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" field. |
| <T> |
Is the size specifier,
encoded in
|
| <Zn> |
Is the name of the source scalable vector register, encoded in the "Zn" field. |
| <Tb> |
Is the size specifier,
encoded in
|
| <const> |
Is the immediate shift amount, in the range 1 to number of bits per element, encoded in "tsz:imm3". |
CheckSVEEnabled(); integer elements = VL DIV (2 * esize); bits(VL) operand = Z[n]; bits(VL) result; integer round_const = 1 << (shift-1); for e = 0 to elements-1 bits(2*esize) element = Elem[operand, e, 2*esize]; integer res = (UInt(element) + round_const) >> shift; Elem[result, 2*e + 0, esize] = res<esize-1:0>; Elem[result, 2*e + 1, esize] = Zeros(); Z[d] = result;
If FEAT_SVE2 is enabled or FEAT_SME is enabled, then when PSTATE.DIT is 1:
Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41
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