SuperH (SH) 64-bit RISC Series SH-5 System Architecture, Volume ...

PRELIMINARY DATA
WP channel type BR 161
1.14.3 Precondition checking for events and RTE
When an event is traced, the DM.WP_BRX_FILTER.SR_MD_ENABLE field is checked
against the CPU mode (SR.MD) of the interrupted or excepting instruction.
This allows the branch channel to filter between interrupts/exceptions occurring in
user mode and those occurring in privileged mode.
When an RTE is traced, the DM.WP_BRX_FILTER.SR_MD_ENABLE field is checked
against the CPU mode (SR.MD) of the first instruction executed after the RTE.
This allows the branch channel to filter between RTEs which return to user mode
and those which return to privileged mode.
An RTE instruction may return to a user-mode instruction which itself excepts and
causes a new exception handler to be launched. In this case, it is
implementation-defined whether the user-mode instruction is treated as having run
in user mode or privileged mode. The DM.WP_BRX_FILTER.SR_MD_MODE bits might
not work as expected in this situation.
1.14.4 Source and destination addresses in branch trace
messages
Table 59 defines the selection of source and destination addresses for branch trace
messages in a number of situations. The branch source address is always the
address of the most recent completed instruction occurring before the jump in PC
value. In particular, this means an excepting instruction’s PC can never be shown as
the source of a branch.
Scenario No. a Source
Destination
(See footnote c )
D R A FT
Branch
type b
SHmedia branch at PC=X, target PC=Y X Y Branch
SHcompact non-delayed branch at PC=X, target PC=Y X Y Branch
SHcompact delayed branch at PC=X, target PC=Y X+2 Y Branch
RTE at PC=X, new PC=Y, Y does not except X Y RTE
Table 59: Selection of branch source and destination addresses
05-SA-10003 v1.0
SuperH, Inc.
SH-5 System Architecture, Volume 3: Debug