Motorola MPC533 Reference Manual page 974

Program Trace
RCPU
Bits
4:5
0:3
22.3.2.3 Correction Messages
In case of a mispredicted branch or an exception, a program trace correction message may
also be sent indicating a number which corrects the number of instructions (not messages)
in the trace.
In the case of a synchronizing branch trace message getting corrected due to a
misprediction or an exception, the next branch trace message will be a synchronizing
message.
Table 22-27 illustrates an example of a program trace correction message in case of a
mispredicted branch.
In case of a mispredicted branch, the correction count is always
1 and the sequential instruction count is reset to 1 (to denote the
not-taken branch as a sequential instruction), after the program
trace correction message is sent. This is because a mispredicted
branch is considered to be a sequential instruction.
Table 22-28 illustrates an example of a program trace correction message in case of an
exception.
In case of an exception, the sequential instruction count is reset
to 0, after the program trace correction message is sent.
Table 22-27. Program Trace Correction Due to a Mispredicted Branch
Time
1
2
3
4
5
22-42
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Table 22-26. Bit Pointer Format
Nexus
Name
Bits
0:1 —
2:5 BP
Processor State
Sequential Instruction
Sequential Instruction
Sequential Instruction
Sequential Instruction
Sequential Instruction
MPC533 Reference Manual
Reserved (Unused)
Bit pointer. This value is 1/2 of the actual bit position on
which the instruction starts.
NOTE
NOTE
Message sent
Description
MOTOROLA