360 Assembly/360 Instructions/MR

MR - Multiply Register - Opcode 1C

Format

 * MR 2,7

The specific syntax is
 * MR target register, source register.


 * The first argument is a one with lesser number of pair of target registers which value is affected by the instruction.
 * The second argument is the source value register.

Availability
The MR instruction is available on all models of the 360, 370 and z/System.

Operation
The MR instruction does multiply of two signed 32-bit integers. The first multiplicand is got from the general register T+1, where T is number of the target register (first operand). The second multiplicand is got from the source register (second operand). The resulting product as 64-bit signed value is then placed into registers T (most significand 32 bits) and T+1 (least significand 32 bits). The target register number T shall be even.

The Condition Code field in the Program Status Word is not changed.

Exceptions and Faults

 * If an odd register number is specified as the target register, operation exception occurs.

Related instructions

 * To multiply by word value from memory, see M.
 * To divide by word value from register, see DR.
 * To add word value from register, see AR.
 * To add value and set condition codes according to unsigned arithmetic, or add not most significant part of multi-word integer value, see AL or ALR.
 * To multiply floating-point values, see MER, MDR, ME or MD.