Compare Bytes Left-Adjusted with Pad (CMPBLAP)

Instruction Syntax

Op Code (Hex) Extender Operand 1 Operand 2 Operand 3 Operand 4 [5, 6]
CMPBLAPB 1CC3 Branch options Compare operand 1 Compare operand 2 Pad Branch targets
CMPBLAPI 18C3 Indicator options Compare operand 1 Compare operand 2 Pad Indicator targets
Operand 1: Numeric scalar or character scalar.

Operand 2: Numeric scalar or character scalar.

Operand 3: Numeric scalar or character scalar.

Operand 4 [5, 6]:

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

Description:

This instruction compares the logical string values of two left-adjusted compare operands (padded if needed). The logical string value of the first compare operand is compared with the logical string value of the second compare operand. Based on the comparison, the resulting condition is used with the extender field to:

  • Transfer control conditionally to the instruction indicated in one of the branch target operands (branch form).
  • Assign a value to each of the indicator operands (indicator form).
The compare operands can be either character or numeric. Any numeric operands are interpreted as logical character strings.

The compare operands are compared byte by byte, from left to right with no numeric conversions being performed.

The length of the operation is equal to the length of the longer of the two compare operands. The shorter of the two compare operands is logically padded on the right with the 1-byte value indicated in the pad operand. If the pad operand is more than 1 byte in length, only its leftmost byte is used. The comparison begins with the leftmost byte of each of the compare operands and proceeds until all the bytes of the longer of the two compare operands have been compared or until the first unequal pair of bytes is encountered. All excess bytes in the longer of the two compare operands are compared to the pad value.

Substring operand references that allow for a null substring reference (a length value of zero) may be specified for operands 1 and 2. The effect of specifying a null substring reference for one of the compare operands is that the other compare operand is compared with an equal length string of pad character values. When a null substring reference is specified for both compare operands, the resultant condition is equal.

Substring operand references that allow for a null substring reference (a length value of zero) may not be specified for operand 3.

Resultant Conditions

The scalar first compare operand's string value is one of the following as compared to the second compare operand.

  • Higher
  • Lower
  • Equal

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
  • 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