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Home > A64 SIMD Scalar Instructions > UQSHRN (scalar) |
Unsigned saturating Shift Right Narrow (immediate).
UQSHRN
Vb
d
, Va
n
, #shift
Where:
Vb
d
Va
n
shift
Unsigned saturating Shift Right Narrow (immediate). This instruction reads each vector element in the source SIMD and FP register, right shifts each result by an immediate value, saturates each shifted result to a value that is half the original width, puts the final result into a vector, and writes the vector to the lower or upper half of the destination SIMD and FP register. All the values in this instruction are unsigned integer values. The results are truncated. For rounded results, see 19.103 UQRSHRN (scalar).
The UQSHRN
instruction writes the vector to the lower half of the destination register and clears the upper half, while the UQSHRN2
instruction writes the vector to the upper half of the destination register without affecting the other bits of the register.
If overflow occurs with any of the results, those results are saturated. If saturation occurs, the cumulative saturation bit FPSR.QC is set.
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.
The following table shows the valid specifier combinations:
Table 19-33 UQSHRN (Scalar) specifier combinations
Vb |
Va |
shift |
---|---|---|
B | H | 1 to 8 |
H | S | 1 to 16 |
S | D | 1 to 32 |