sysperfana/perfinvestigator/com.nokia.carbide.cpp.pi.doc.user/html/reference/methods/curr_pgm_status_reg.htm
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1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> |
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6 <title>Current Program Status Register Value</title> |
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10 <body> |
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11 <h3>Current Program Status Register Value</h3> |
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12 <p> In ARM architecture, the current |
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13 program status register (CPSR) is an unbanked register, thus it |
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14 refers to the same physical register in all processor |
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15 modes. It contains condition code flags, interrupt disable bits, |
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16 the current processor mode, and other status and control |
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17 information. The state of the processor reflects changes in the |
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18 flags and values within the CPSR. CPSR cannot be changed while |
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19 in user mode, thus preventing the software from accessing privileged resources. However, CPSR values |
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20 can be investigated within user mode, making it possible to |
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21 distinguish the current processor mode at all times. Performance |
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22 measurements may require such investigation of the CPSR in order |
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23 to distinguish the modes and to select appropriate actions |
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24 according to the mode. Without such precautions, exceptions or |
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25 fault situations might take place.</p> |
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26 <div id="footer">Copyright © 2009 Nokia Corporation and/or its subsidiary(-ies). All rights reserved. <br>License: <a href="http://www.eclipse.org/legal/epl-v10.html">http://www.eclipse.org/legal/epl-v10.html</a></div> |
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28 </html> |