Hexadecimal floating point multiplication and addition instruction

Executing an instruction to perform an operation selected from a plurality of operations configured for the instruction includes determining a value of a selected operand of the instruction. Determining the value is an instruction-based control and includes reading a selected operand of the instruction from a selected operand location to obtain a value of the selected operand based on the instruction-based control having a first value, and using a predetermined value as the value of the selected operand based on the instruction-based control having a second value. The value is multiplied by another selected operand of the instruction to obtain a product. An arithmetic operation is performed using the product and a selected operand of the instruction to obtain an intermediate result. A result is obtained from the intermediate result, and the result is placed in a selected location. 执行指令以执行从针对该指令所配置的多个操作中选择的操作，执行指令包括：确定指令的选定操作数的值。确定值是基于指令的控件并且包括：基于指令的控件具有第一值，从选定操作数位置读取指令的选定操作数以获得选定操作数的值，以及基于指令的控件具有第二值，使用预定值作为选定