Freescale Semiconductor StarCore SC140 - Manual (Page 137)

EOnCE Module Internal Architecture
SC140 DSP Core Reference Manual 4-27
— Return from exception instructions
• Other change of flow events:
— Interrupts
— Hardware loops
• Any execution set
• Mark instructions
For each change-of-flow event, a package of information is stored in the trace buffer, including the PC of
the source, the PC of the destination, and, optionally, the value of the event counter and the counter
extension.
The EOnCE trace unit:
• Supports a circular hardware trace buffer external to the core. Each entry is 32-bit long. The number
of entries is derivative-specific.
• Traces change-of-flow instructions, normal execution, hardware loops, and interrupts.
• Operates during real-time processing.
• Can be read by the debugging hardware during execution state as well as debug state when the trace
buffer is disabled.
The trace buffer can be enabled by the host, core software, or by an EOnCE event generated by various ES
configurations.
The following addresses can be traced:
• The PC of an execution set containing a taken change-of-flow instruction, followed by its target
address.
• The PC of the last execution set executed before servicing an interrupt, followed by the address of
the interrupt. See more on interrupt tracing in
Section 4.5.5.1, “Change of Flow and Interrupt
Tracing,” )
• The PC of every execution set issued.
• The last address for short hardware loops and the last address followed by the start address for long
hardware loops.
• The PC of each execution set that includes the MARK instruction.