© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 01 — 15 August 2005
323
Philips Semiconductors
UM10139
Volume 1
Chapter 24: RealMonitor
24.4.5 Prefetch
Abort
mode
RealMonitor uses four words on entry to its Prefetch abort interrupt handler.
24.4.6 Data
Abort
mode
RealMonitor uses four words on entry to its data abort interrupt handler.
24.4.7 User/System
mode
RealMonitor makes no use of this stack.
24.4.8 FIQ
mode
RealMonitor makes no use of this stack.
24.4.9 Handling
exceptions
This section describes the importance of sharing exception handlers between
RealMonitor and user application.
24.4.10 RealMonitor exception handling
To function properly, RealMonitor must be able to intercept certain interrupts and
exceptions.
illustrates how exceptions can be claimed by RealMonitor itself, or
shared between RealMonitor and application. If user application requires the exception
sharing, they must provide function (such as app_IRQDispatch ()). Depending on the
nature of the exception, this handler can either:
•
Pass control to the RealMonitor processing routine, such as rm_irqhandler2().
•
Claim the exception for the application itself, such as app_IRQHandler ().
In a simple case where an application has no exception handlers of its own, the
application can install the RealMonitor low-level exception handlers directly into the vector
table of the processor. Although the IRQ handler must get the address of the Vectored
Interrupt Controller. The easiest way to do this is to write a branch instruction (<address>)
into the vector table, where the target of the branch is the start address of the relevant
RealMonitor exception handler.