Unsigned byte / halfword / word extend (predicated)
Zero-extend the least-significant sub-element of each active element of the source vector, and place the results in the corresponding elements of the destination vector. Inactive elements in the destination vector register remain unmodified or are set to zero, depending on whether merging or zeroing predication is selected.
It has encodings from 6 classes: Byte, merging , Byte, zeroing , Halfword, merging , Halfword, zeroing , Word, merging and Word, zeroing
| 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 | 0 | size | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | Pg | Zn | Zd | |||||||||||
| M | U | ||||||||||||||||||||||||||||||
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 s_esize = 8; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean unsigned = TRUE; constant boolean merging = TRUE;
| 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 | 0 | size | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | Pg | Zn | Zd | |||||||||||
| M | U | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2p2) && !IsFeatureImplemented(FEAT_SME2p2) then EndOfDecode(Decode_UNDEF); if size == '00' then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer s_esize = 8; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean unsigned = TRUE; constant boolean merging = FALSE;
| 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 | 0 | size | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | Pg | Zn | Zd | |||||||||||
| M | U | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); if size IN {'0x'} then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer s_esize = 16; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean unsigned = TRUE; constant boolean merging = TRUE;
| 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 | 0 | size | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | Pg | Zn | Zd | |||||||||||
| M | U | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2p2) && !IsFeatureImplemented(FEAT_SME2p2) then EndOfDecode(Decode_UNDEF); if size IN {'0x'} then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer s_esize = 16; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean unsigned = TRUE; constant boolean merging = FALSE;
| 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 | 0 | size | 0 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | Pg | Zn | Zd | |||||||||||
| M | U | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); if size != '11' then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer s_esize = 32; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean unsigned = TRUE; constant boolean merging = TRUE;
| 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 | 0 | size | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | Pg | Zn | Zd | |||||||||||
| M | U | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2p2) && !IsFeatureImplemented(FEAT_SME2p2) then EndOfDecode(Decode_UNDEF); if size != '11' then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer s_esize = 32; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean unsigned = TRUE; constant boolean merging = FALSE;
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" field. |
| <Pg> |
Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field. |
| <Zn> |
Is the name of the source scalable vector register, encoded in the "Zn" field. |
CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) mask = P[g, PL]; constant bits(VL) operand = if AnyActiveElement(mask, esize) then Z[n, VL] else Zeros(VL); bits(VL) result = if merging then Z[d, VL] else Zeros(VL); for e = 0 to elements-1 if ActivePredicateElement(mask, e, esize) then constant bits(esize) element = Elem[operand, e, esize]; Elem[result, e, esize] = Extend(element<s_esize-1:0>, esize, unsigned); Z[d, VL] = result;
If PSTATE.DIT is 1:
The merging variant of this instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and the merging variant of this instruction is CONSTRAINED UNPREDICTABLE:
Internal version only: aarchmrs v2024-12_rel, pseudocode v2024-12_rel ; Build timestamp: 2024-12-15T22:18
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