Freescale Semiconductor e200z3 Reference Manual page 394

Nexus3/Nexus2+ Module
branch/predicate history information from subsequent messages to obtain the complete branch/predicate
history between indirect changes of flow.
For instruction counter overflow, the resource full message transmits an RCODE of 0b0000 and a value
of 0xFF is transmitted in the RDATA field, indicating that 255 sequential instructions have been executed
since the last change of flow or, if program trace is in history mode, since the last instruction that recorded
history information
Table 10-23 shows the RCODE encodings and RDATA information used for Resource Full messages.
RCODE
0000 0xFF
Branch history. This type of packet is terminated
0001
by a stop bit set after the last history bit.
10.7.2.5 Debug Status Messages
Debug status messages report low-power mode and debug status. Debug status messages are enabled when
Nexus 3 is enabled. Entering/exiting debug mode as well as entering a low-power mode triggers a debug
status message, indicating the value of the most significant byte in the development status register. Debug
status information is sent out in the format shown in
10.7.2.6 Program Correlation Messages
Program correlation messages (PCMs) are used to correlate events to the program flow that may not be
associated with the instruction stream. The following events will result in a PCM when program trace is
enabled:
• When the CPU enters debug mode, a PCM is generated. The instruction count and history
information provided by the PCM can be used to determine the last sequence of instructions
executed prior to debug mode entry.
10-28
(1–32 bits)
Branch History
Maximum length = 46 bits; minimum length = 15 bits
Figure 10-21. Resource Full Message Format
Table 10-23. RCODE Encoding
RDATA field
(8 bits)
31–24
Fixed length = 18 bits
Figure 10-22. Debug Status Message Format
e200z3 Power Architecture Core Reference Manual, Rev. 2
(4 bits)
RCODE (0001) Source Process
Description
Program trace instruction counter reached 255 and was reset.
Program trace, branch/predicate instruction history full.
Figure 10-22:
(4 bits) (6 bits)
Source Process TCODE (000000)
(4 bits) (6 bits)
TCODE
(011011)
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