Multiply (MULT)

Instruction Syntax

Operand 1: Numeric variable scalar.

Operand 2: Numeric scalar.

Operand 3: Numeric scalar.

Operand 4-7:

• Branch Form–Branch point, instruction pointer, relative instruction number, or absolute instruction number.
• Indicator Form–Numeric variable scalar or character variable scalar.

Short forms

Operand 1: Numeric variable scalar.

Operand 2: Numeric scalar.

Operand 3-6:

• Branch Form–Branch point, instruction pointer, relative instruction number, or absolute instruction number.
• Indicator Form–Numeric variable scalar or character variable scalar.

Description:

The product is the result of multiplying the multiplicand and the multiplier.

Operands can have floating-point, packed or zoned decimal, signed or unsigned binary type.

Source operands are the multiplicand and multiplier. The receiver operand is the product.

If operands are not of the same type, source operands are converted according to the following rules:

1. If any one of the operands has floating point type, source operands are converted to floating point type.
2. Otherwise, if any one of the operands has zoned or packed decimal type, source operands are converted to packed decimal.
3. Otherwise, the binary operands are converted as follows.
   1. If an unsigned binary(2) source operand is used with a signed binary operand of any length, the unsigned binary(2) is viewed as a signed binary(4).
   2. If both source operands are signed binary (including cases resulting from use of 3.a), then a signed operation, of the length of the longer operand, is done.
   3. If both source operands are unsigned binary(2), then an unsigned 2-byte operation is done.
   4. If either source operand is unsigned binary(4), then an unsigned 4-byte operation is done with overflow detection disabled until the assignment to the receiver.

Source operands are multiplied according to their type. Floating point operands are multiplied using floating point multiplication. Packed decimal operands are multiplied using packed decimal multiplication. Unsigned binary multiplication is used with unsigned source operands, except as noted above. Signed binary operands are multiplied using two's complement binary multiplication.

Better performance can be obtained if all operands have the same type. Signed and unsigned binary multiplication execute faster than either packed decimal or floating point multiplication.

The operands must be numeric with any implicit conversions occurring according to the rules of arithmetic operations as outlined in the Arithmetic Operations.

Decimal operands used in floating-point operations cannot contain more than 15 total digit positions.

If the multiplicand operand or the multiplier operand has a value of 0, the result of the multiplication is a zero product.

For a decimal operation, no alignment of the assumed decimal point is performed for the multiplier and multiplicand operands.

The operation occurs using the specified lengths of the multiplicand and multiplier operands with no logical zero padding on the left necessary.

Floating-point multiplication uses exponent addition and significand multiplication.

For nonfloating-point computations and for significand multiplication for floating-point operations, the multiplication operation is performed according to the rules of algebra. Unsigned binary operands are treated as positive numbers for the algebra.

The result of the operation is copied into the product operand. If this operand is not the same type as that used in performing the operation, the resultant value is converted to its type. If necessary, the resultant value is adjusted to the length of the product operand, aligned at the assumed decimal point of the product operand, or both before being copied to it. Length adjustment and decimal point alignment are performed according to the rules of arithmetic operations outlined in the Arithmetic Operations.

For the optional round form of the instruction, specification of a floating-point receiver operand is invalid.

For fixed-point operations in programs that request to be notified of size exceptions, if nonzero digits are truncated from the left end of the resultant value, a size (hex 0C0A) exception is signaled.

For floating-point operations involving a fixed-point receiver field (if nonzero digits would be truncated from the left end of the resultant value), an invalid floating-point conversion (hex 0C0C) exception is signaled.

For a floating-point product operand, if the exponent of the resultant value is either too large or too small to be represented in the product field, the floating-point overflow (hex 0C06) exception or the floating-point underflow (hex 0C07) exception is signaled.

If operands overlap but do not share all of the same bytes, results of operations performed on these operands are not predictable. If overlapped operands share all of the same bytes, the results are predictable when direct addressing is used. If indirect addressing is used (that is, based operands, parameters, strings with variable lengths, and arrays with variable subscripts), the results are not always predictable.

If a decimal to binary conversion causes a size (hex 0C0A) exception to be signaled, the binary value contains the correct truncated result only if the decimal value contains 15 or fewer significant nonfractional digits.

Resultant Conditions

• Positive–The algebraic value of the numeric scalar product is positive.
• Negative–The algebraic value of the numeric scalar product is negative.
• Zero–The algebraic value of the numeric scalar product is zero.
• Unordered–The value assigned a floating-point product operand is NaN.

Authorization Required

• None

Lock Enforcement

• None

Exceptions

• 06 Addressing
  • 0601 Space Addressing Violation
  • 0602 Boundary Alignment
  • 0603 Range
• 08 Argument/Parameter
  • 0801 Parameter Reference Violation
• 0C Computation
  • 0C02 Decimal Data
  • 0C06 Floating-Point Overflow
  • 0C07 Floating-Point Underflow
  • 0C09 Floating-Point Invalid Operand
  • 0C0A Size
  • 0C0C Invalid Floating-Point Conversion
  • 0C0D Floating-Point Inexact Result
• 10 Damage Encountered
  • 1004 System Object Damage State
  • 1044 Partial System Object Damage
• 1C Machine-Dependent
  • 1C03 Machine Storage Limit Exceeded
• 20 Machine Support
  • 2002 Machine Check
  • 2003 Function Check
• 22 Object Access
  • 2201 Object Not Found
  • 2202 Object Destroyed
  • 2203 Object Suspended
  • 2208 Object Compressed
  • 220B Object Not Available
• 24 Pointer Specification
  • 2401 Pointer Does Not Exist
  • 2402 Pointer Type Invalid
• 2C Program Execution
  • 2C04 Branch Target Invalid
• 2E Resource Control Limit
  • 2E01 User Profile Storage Limit Exceeded
• 36 Space Management
  • 3601 Space Extension/Truncation
• 44 Protection Violation
  • 4401 Object Domain or Hardware Storage Protection Violation
  • 4402 Literal Values Cannot Be Changed