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Home > A64 SIMD Vector Instructions > PMULL, PMULL2 (vector) |
Polynomial Multiply Long.
PMULL{2}
Vd
.Ta
, Vn
.Tb
, Vm
.Tb
Where:
2
Vd
Ta
8H
.
Vn
Tb
Vm
Polynomial Multiply Long. This instruction multiplies corresponding elements in the lower or upper half of the vectors of the two source SIMD and FP registers, places the results in a vector, and writes the vector to the destination SIMD and FP register. The destination vector elements are twice as long as the elements that are multiplied.
For information about multiplying polynomials see Polynomial arithmetic over {0, 1} in the ARM Architecture Reference Manual ARMv8, for ARMv8-A architecture profile.
The PMULL
instruction extracts each source vector from the lower half of each source register, while the PMULL2
instruction extracts each source vector from the upper half of each source register.
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 20-31 PMULL, PMULL2 (Vector) specifier combinations
<Q> | Ta |
Tb |
---|---|---|
- | 8H | 8B |
2 | 8H | 16B |