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<title>6.2 Exception vector table</title>

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  <a name="1102222"> </a><font color="#003366"  face="Verdana, Arial, Helvetica, sans-serif">6.2 	 Exception vector table</font>
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  <a name="1102223"> </a><font size=2  face="Verdana, Arial, Helvetica, sans-serif">The exception vector table maps each exception level to a user process or exception. The base of the exception vector table is at the fixed address <em>ExceptionBase</em> (#80000040) in on-chip memory, and the exception level is the word offset from the <em>ExceptionBase</em> to the vector. Thus the exception level is used as an index into the exception vector table. </font>
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  <a name="1102225"> </a><font size=2  face="Verdana, Arial, Helvetica, sans-serif">The address of the user process or exception is always word aligned, and so has bits 0 and 1 set to zero. The entry in the exception vector table is a descriptor, which consists of the address of the user process or exception ORed with a type. The type is bit 0 of the descriptor, and so can be either <em>ExceptionProcessType</em> (which has the value 1) or <em>UserProcessType</em> (which has the value 0). The type allows each exception level to be assigned to one of the following.</font>
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<p>  <font size=2  face="Verdana, Arial, Helvetica, sans-serif"><li ><a name="1102231"> </a>An exception handler. The entry for an exception handler is the address of the exception control block (as described in <a href="except4.htm#1102249"><font  color="#0000ff" face="Verdana, Arial, Helvetica, sans-serif"><i>Section

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