vmul10ecuq
Vector Multiply-by-10 Extended & write Carry-out Unsigned Quadword
Multiplies the unsigned quadword integer in vector register VA by 10, adds the least-significant bit of VB as a carry-in digit, and writes the carry-out of the result to vector register VX.
Details
Multiplies the unsigned 128-bit quadword in vector register VA by 10, adds the least-significant bit of VB as a carry-in, and writes only the carry-out (overflow) of the result to vector register VX. The result discards the low 128 bits, retaining only the high carry. This instruction requires VMX/AltiVec support and no condition registers are modified.
Pseudocode Operation
product ← (VA) × 10 + ((VB)[127] as carry-in)
VX ← product[128:191]Programming Note
This instruction is ideal for high-performance multi-precision decimal arithmetic, especially when performing chained multiply-by-10 operations. Ensure that the input values in VA and VB are correctly aligned as unsigned 128-bit integers to avoid unexpected results. The carry-out written to VX should be used as the extended carry-in for subsequent operations to maintain precision.
Example
Encoding
Operands
-
VX
Target Vector Register -
VA
Source Vector Register -
VB
Source Vector Register