Logical shift left variable
This instruction shifts a register value left by a variable number of bits, shifting in zeros, and writes the result to the destination register. The value of the second source register modulo the register size in bits gives the number of bits by which the first source register is left-shifted.
This instruction is used by the alias LSL (register).
| 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 |
| sf | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | Rm | 0 | 0 | 1 | 0 | 0 | 0 | Rn | Rd | ||||||||||||
| S | op2 | ||||||||||||||||||||||||||||||
constant integer d = UInt(Rd); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant integer datasize = 32 << UInt(sf); constant ShiftType shift_type = DecodeShift(op2);
| <Wd> |
Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field. |
| <Wn> |
Is the 32-bit name of the first general-purpose source register, encoded in the "Rn" field. |
| <Wm> |
Is the 32-bit name of the second general-purpose source register holding a shift amount from 0 to 31 in its bottom 5 bits, encoded in the "Rm" field. |
| <Xd> |
Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field. |
| <Xn> |
Is the 64-bit name of the first general-purpose source register, encoded in the "Rn" field. |
| <Xm> |
Is the 64-bit name of the second general-purpose source register holding a shift amount from 0 to 63 in its bottom 6 bits, encoded in the "Rm" field. |
constant bits(datasize) operand2 = X[m, datasize]; X[d, datasize] = ShiftReg(n, shift_type, UInt(operand2) MOD datasize, datasize);
If PSTATE.DIT is 1:
Internal version only: aarchmrs v2024-12_rel, pseudocode v2024-12_rel ; Build timestamp: 2024-12-15T22:18
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