MOTOROLA
Chapter 37. System Development and Debugging
37-1
Chapter 37
System Development and Debugging
370
370
Emulators require a level of control and observation that is in sharp contrast to the trend of
modern microcomputers and microprocessors in which many bus cycles are directed to
internal resources and are not externally visible. The same is true for bus analyzers. To help
development tools support, some development support functions are implemented in the
silicon. Program ßow tracking, internal watchpoint and breakpoint generation, and
emulation systems control over the activity of the core (debug mode) are some of the
features that allow the user to efÞciently debug MPC860-based systems.
37.1 Tracking Program Flow
The MPC860 provides many options for tracking program ßows that impact performance
in varying degrees.
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In one mode, signals provided for tracking code ßow can be captured externally and
then parsed by a post-processing program. This mode is described more fully in
subsequent sections.
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In another, slower mode, instruction ßow is visible on the external bus when the
MPC860 is programmed to operate in serialized mode with all fetch cycles shown
on the external bus. Although instruction ßow tracking is simpler, performance is
much lower than in regular mode. Section 37.5.1.3, ÒInstruction Support Control
Register (ICTRL),Ó describes programming of the core to operate in this mode.
The MPC860 implements a prefetch queue combined with parallel, out-of-order, and
pipelined execution. These features, plus the fact that most fetch cycles are performed
internally (from the I-cache), increase performance but make it very difÞcult to provide the
user with the real program trace. Instructions progress inside the core from fetch to
retirement. An instruction retires from the machine only after it and all preceding
instructions Þnish execution with no exception. Therefore, only retired instructions can be
considered architecturally executed.
To reconstruct program trace, the program code, combined with additional MPC860
information, is required. Reporting program trace during retirement signiÞcantly
complicates the implementation in two ways: more than one instruction can retire in a clock
cycle; and, it is harder to report on indirect branches during retirement. Because of this,
program trace is deciphered by monitoring fetched code and instruction queue ßushes, and
Summary of Contents for MPC860 PowerQUICC
Page 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Page 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
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Page 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
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Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
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Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Page 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
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Page 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 660: ...22 28 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
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Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
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