In thumb code adr can only generate word aligned

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Unformatted text preview: am). Look at the assembly code generated by the C compiler (using the '-s' option). Compare the code size and the execution time with the same programs compiled into ARM code. Exercise 7.1.2 Architectural Support for System Development Summary of chapter contents Designing any computer system is a complex task; designing an embedded 'system-on-chip' is a daunting one. The development often takes place entirely within a CAD environment, and the first silicon must not only function but it must deliver the necessary performance and be manufacturable. The only scope for fixing design flaws is in the software; to modify the chip in order to correct errors takes too long and usually incurs considerable cost. For the past two decades the principal approach to microprocessor system development has been based upon the In-Circuit Emulator (ICE). The system itself was a printed circuit board incorporating a microprocessor chip and various memory and peripheral devices. To use the ICE, the microprocessor was removed from its socket and replaced by a header plug with an umbilical connection to the ICE equipment. The ICE emulated the function of the microprocessor and gave the user an inside view on the internal state of the system, giving access to read and modify processor registers and memory values, to set breakpoints, and so on. Now that the microprocessor itself has become just a cell on a larger chip, this whole approach has collapsed. It is not possible to unplug part of a chip! There is, as yet, no approach that has replaced the ICE in all its roles, but there are several techniques that contribute, some of which require explicit support in the processor's architecture. This chapter covers the techniques available to support the development of system chips based on ARM cores and the architectural features built into the cores to assist in this process. 207 208 Architectural Support for System Development 8.1 The ARM memory interface In this section we look at the general principles involved in connecting an ARM processor to a memory system built...
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This document was uploaded on 10/30/2011 for the course CSE 378 380 at SUNY Buffalo.

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