SQDMULL, SQDMULL2 (vector)

Signed saturating Doubling Multiply Long. This instruction multiplies corresponding vector elements in the lower or upper half of the two source SIMD&FP registers, doubles the results, places the final results in a vector, and writes the vector to the destination SIMD&FP register.

If overflow occurs with any of the results, those results are saturated. If saturation occurs, the cumulative saturation bit FPSR.QC is set.

The SQDMULL instruction extracts each source vector from the lower half of each source register. The SQDMULL2 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.

It has encodings from 2 classes: Scalar and Vector

Scalar

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); if size == '00' || size == '11' then UNDEFINED; integer esize = 8 << UInt(size); integer datasize = esize; integer elements = 1; integer part = 0;

Vector

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); if size == '00' || size == '11' then UNDEFINED; integer esize = 8 << UInt(size); integer datasize = 64; integer part = UInt(Q); integer elements = datasize DIV esize;