HD6417144 RENESAS [Renesas Technology Corp], HD6417144 Datasheet - Page 156

• Manufacturer Part Number: HD6417144
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family/SH7144 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

7. User Break Controller (UBC)
7.5.3
If a user break is set for the fetch of a particular instruction, and exception processing with higher
priority than a user break is in contention and is accepted in the decode stage for that instruction
(or the next instruction), user break exception processing may not be performed after completion
of the higher-priority exception service routine (on return by RTE).
Thus, if a user break condition is specified to the branch destination instruction fetch after a
branch (BRA, BRAF, BT, BF, BT/S, BF/S, BSR, BSRF, JMP, JSR, RTS, RTE, exception
processing), and that branch instruction accepts an exception processing with higher priority than a
user break interrupt, user break exception processing is not performed after completion of the
exception service routine.
Therefore, a user break condition should not be set for the fetch of the branch destination
instruction after a branch.
7.5.4
When a branch instruction without delay slot (including exception processing) jumps to the
destination instruction by executing the branch, a user break will not be generated even if a user
break condition has been set for the first jump destination instruction fetch.
7.5.5
The UBC can set the module disable/enable by using the module standby control register 2
(MSTCR2). By releasing the module standby mode, register access becomes to be enabled.
By setting the MSTP0 bit of MSTCR2 to 1, the UBC is in the module standby mode in which the
clock supply is halted. See section 24, Power-Down Modes, for further details.
Rev.4.00 Mar. 27, 2008 Page 112 of 882
REJ09B0108-0400
Contention between User Break and Exception Processing
Break at Non-Delay Branch Instruction Jump Destination
Module Standby Mode Setting