URSHL

Unsigned Rounding Shift Left (register). This instruction takes each element in the vector of the first source SIMD&FP register, shifts the vector 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 rounding right shift.

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

Scalar

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); integer esize = 8 << UInt(size); 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;

Vector

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); if size:Q == '110' then UNDEFINED; integer esize = 8 << UInt(size); integer datasize = if Q == '1' then 128 else 64; integer elements = datasize DIV esize; boolean unsigned = (U == '1'); boolean rounding = (R == '1'); boolean saturating = (S == '1');