Unsigned Shift Left (register). This instruction takes each element in the vector of the first source SIMD&FP register, shifts each element by a value from the least significant byte of the corresponding element of the second source SIMD&FP register, places the results in a vector, and writes the vector to the destination SIMD&FP register.
If the shift value is positive, the operation is a left shift. If the shift value is negative, it is a truncating right shift. For a rounding shift, see URSHL.
Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.
It has encodings from 2 classes: Scalar and Vector
| 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 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | Rm | 0 | 1 | 0 | 0 | 0 | 1 | Rn | Rd | ||||||||||||
| U | size | R | S | ||||||||||||||||||||||||||||
integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); constant integer esize = 8 << UInt(size); constant integer datasize = esize; integer elements = 1; boolean unsigned = (U == '1'); boolean rounding = (R == '1'); boolean saturating = (S == '1'); if S == '0' && size != '11' then UNDEFINED;
| 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 | Q | 1 | 0 | 1 | 1 | 1 | 0 | size | 1 | Rm | 0 | 1 | 0 | 0 | 0 | 1 | Rn | Rd | |||||||||||||
| U | R | S | |||||||||||||||||||||||||||||
integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); if size:Q == '110' then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean unsigned = (U == '1'); boolean rounding = (R == '1'); boolean saturating = (S == '1');
| <d> |
Is the number of the SIMD&FP destination register, in the "Rd" field. |
| <n> |
Is the number of the first SIMD&FP source register, encoded in the "Rn" field. |
| <m> |
Is the number of the second SIMD&FP source register, encoded in the "Rm" field. |
| <Vd> |
Is the name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <T> |
Is an arrangement specifier,
encoded in
|
| <Vn> |
Is the name of the first SIMD&FP source register, encoded in the "Rn" field. |
| <Vm> |
Is the name of the second SIMD&FP source register, encoded in the "Rm" field. |
CheckFPAdvSIMDEnabled64(); bits(datasize) operand1 = V[n, datasize]; bits(datasize) operand2 = V[m, datasize]; bits(datasize) result; boolean sat; for e = 0 to elements-1 integer element = Int(Elem[operand1, e, esize], unsigned); integer shift = SInt(Elem[operand2, e, esize]<7:0>); if shift >= 0 then // left shift element = element << shift; else // right shift shift = -shift; element = RShr(element, shift, rounding); if saturating then (Elem[result, e, esize], sat) = SatQ(element, esize, unsigned); if sat then FPSR.QC = '1'; else Elem[result, e, esize] = element<esize-1:0>; V[d, datasize] = result;
If PSTATE.DIT is 1:
Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46
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