PH42050: 20-BIT ADDRESSABILITY FOR DEPENDENT USING

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A dependent USING statement is currently required to be resolved
  using 12-bit addressing.  For programs which use 20-bit
  addressing, this can be an unhelpful limitation.  Also, the
  Using Map report and Active Usings headings may show incorrect
  start and range values if a dependent USING base address is not
  the start of a section.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of HLASM for z/OS, z/VM, z/VSE and     *
  *                 Linux                                        *
  ****************************************************************
  * PROBLEM DESCRIPTION: Dependent USING incorrectly required    *
  *                      12 bit displacement to resolve          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  1. A dependent USING instruction is rejected if the second
     operand address cannot be referenced using a 12-bit
     displacement, although the documentation suggests that a
     20-bit displacement should also be accepted.  This can be
     worked around, but is an unhelpful limitation when writing
     programs that use 20-bit displacements.
  
  2. The USING Map information in the value field for a dependent
     USING was incorrect when the specified base address was not
     the start of a section.  It should always be the offset of
     the second (address) operand from the start of the supporting
     ordinary USING.  Similar problems were also present in the
     register offset values shown for dependent USINGs in the
     Active Usings headings.
  
  3. If a USING statement was used to resolve a qualified
     (labeled) dependent USING, the last used statement and
     maximum displacement in the USING Map were incorrectly
     updated even though this should not count as a reference.
  
  4. If an end address is specified on a dependent USING, the
     documentation says that the range will be limited either to
     that end address or to the end address of the original USING,
     whichever is lesser.  This check was not complete, so the
     range of a dependent USING was not being limited by an end
     address specified on the original USING.
  
  5. If the Active Using headers included a nesting depth, there
     should have been one blank before the first USING item.
  

Problem conclusion

• 1. If the selected OPTABLE option supports 20-bit addressing, a
     dependent USING statement is now accepted whenever the second
     operand address is addressable using either a 12-bit
     displacement or a signed 20-bit displacement if necessary.
  
     The displacement value in the object code columns of the
     USING statement is now increased to five hexadecimal digits
     (a signed 20-bit displacement) if the first byte is non-zero.
  
  2. The value field shown in the USING map has been corrected for
     a dependent USING where the base address is not at the start
     of a section.  The offset may now be a negative value when a
     20-bit displacement is used.
  
     The active USING headings have also been corrected for
     similar existing problems with dependent USINGs and updated
     to show correct information for 20-bit dependent USING
     statements.  If the second operand address is not addressable
     by a 12-bit displacement, then the 12-bit range is now shown
     as '(0)'.  Also, if the range of addressability for a
     dependent USING is simply to the end of the base registers,
     the range is omitted, as for an ordinary USING, even if the
     start of range is offset from the first base register.
  
  3. The last used statement and maximum displacement in the USING
     map are no longer updated when the USING statement is being
     used only to resolve another USING statement.
  
  4. If the end address specified on a dependent USING is beyond
     the end address of the original USING, it is now limited to
     match the original USING, as documented.
  
  5. When the Active Using headers include a nesting depth, there
     is now a blank after "(n):" before the first USING item.
  
  DOCUMENTATION UPDATES:
  
  In the HLASM Language Reference, SC26-4940, in the topic
  "Dependent USING instruction", the second sentence of the
  description of the address operand is modified as follows:
  
    The range of an active USING is considered to be that which is
    valid for generating 12 bit displacements, or for signed
    20 bit displacements if the specified OPTABLE level includes
    support for instructions with displacements in this form.
  
  END OF DOCUMENTATION UPDATES
  

Temporary fix

Comments

• ×**** PE22/01/25 FIX IN ERROR. SEE APAR PH42918  FOR DESCRIPTION
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI78084 UI78085 UI78086

Modules/Macros

•    ASMAINFO ASMA2F   ASMA2W   ASMA26   ASMA9Z
  

Fix information

• Fixed component name

  HLASM MVS, VM &

• Fixed component ID

  569623400

Applicable component levels

• R160 PSY UI78085

     UP21/11/17 P F111

• R360 PSY UI78084

     UP21/11/16 P 2111

• R689 PSY UI78086

     UP21/11/16 I 1000

Fix is available

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