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z/VM: CP Commands and Utilities Reference - z/VM - IBM

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Responses<br />

With the use of access registers, the BASE option also lets you examine<br />

storage without needing to know whether the program is currently in access<br />

register mode. This is done automatically for you by <strong>CP</strong>.<br />

6. If the BASEnn <strong>and</strong> INDEXnn oper<strong>and</strong>s are used together, the specified starting<br />

address for display is used as a displacement from the address formed from<br />

the sum of the contents of the two specified registers.<br />

The values in the registers specified by the BASEnn <strong>and</strong> INDEXnn oper<strong>and</strong>s<br />

are treated as 24-bit or 31-bit real addresses according to the addressing<br />

mode (A) bit in the virtual machine’s PSW. That is, if the A bit is 1, the value is<br />

a 31-bit address; if the A bit is 0, the value is a 24-bit address.<br />

7. During DISPLAY comm<strong>and</strong> processing, the authorization mechanisms used<br />

during normal address translation are not used.<br />

8. Special authorization is required to use the SPACE or ASIT oper<strong>and</strong> of this<br />

comm<strong>and</strong> to view any address space other the host-primary address space of<br />

the virtual <strong>CP</strong>U. In order to use this comm<strong>and</strong> to display storage in an address<br />

space, one of the following conditions must be satisfied:<br />

v Your virtual machine must be the owner of the address space. Your virtual<br />

machine is the owner of its host-primary address space <strong>and</strong> of any address<br />

space that it creates using the CREATE function of the ADRSPACE macro.<br />

v If the address space is owned by another virtual machine, your virtual<br />

machine must have read-only or read-write authorization to the address<br />

space. The owner of the address space can grant authorization to your<br />

virtual machine using the PERMIT function of the ADRSPACE macro.<br />

Authorization is granted on a space-by-space basis, so that you may be<br />

authorized to view one address space of a virtual machine, but not to view a<br />

different space.<br />

9. The oper<strong>and</strong>s V <strong>and</strong> W used in displaying third-level storage from guest<br />

primary <strong>and</strong> secondary are supported for compatibility. The PRI <strong>and</strong> SECO<br />

oper<strong>and</strong>s replace the V <strong>and</strong> W oper<strong>and</strong>s.<br />

10. When multiple DISPLAY requests are entered on a single line, the BASEnn<br />

<strong>and</strong> INDEXnn oper<strong>and</strong>s are not applied to subsequent DISPLAY requests on<br />

the comm<strong>and</strong> line. They must be explicitly entered for each DISPLAY request.<br />

11. When the ASIT or SPACE oper<strong>and</strong> is specified, the DISPLAY request will fail if<br />

the specified address space does not exist, or if you are not authorized to<br />

access the address space. The current request is rejected <strong>and</strong> processing of<br />

the comm<strong>and</strong> line is terminated. The rejected oper<strong>and</strong>s are displayed along<br />

with a message indicating the nature of the error.<br />

12. The DISPLAY comm<strong>and</strong> requires a segment table designation (STD) to display<br />

third-level storage (storage that appears virtual to your virtual machine). It may<br />

receive the STD as an oper<strong>and</strong>, find it in a control register, or use the<br />

access-register translation (ART) process or the address space number (ASN)<br />

translation process to obtain the STD. The access-register translation <strong>and</strong> ASN<br />

translation processes may fail because of one of several program exception<br />

conditions. If the translation does not succeed, the current request is rejected,<br />

<strong>and</strong> processing of the comm<strong>and</strong> line is terminated. The rejected oper<strong>and</strong>s are<br />

displayed along with a response indicating the nature of the exception<br />

condition.<br />

13. If you use an underscore, it must be followed by eight hexadecimal digits.<br />

14. For more information, see “Usage Notes” on page 282.<br />

The oper<strong>and</strong>s hexloc1 <strong>and</strong> hexloc2 are storage locations.<br />

DISPLAY Guest Storage (ESA/390)<br />

Chapter 2. <strong>CP</strong> <strong>Comm<strong>and</strong>s</strong> 301

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