SH7124 datasheet(158/782 Pages) RENESAS

158 / 782 page

Section 7

User Break Controller (UBC)

Rev. 3.00

Sep. 27, 2007

Page 138 of 758

REJ09B0243-0300

4. When data access (address + data) is specified as a break condition:

When a data value is added to the break conditions, the address of an instruction that is within

two instructions of the instruction that matched the break condition is saved in the stack. At

which instruction the break occurs cannot be determined accurately.

When a delay slot instruction matches the condition, the branch destination address is saved in

the stack. If the instruction following the instruction that matches the break condition is a

branch instruction, the break may occur after the branch instruction or delay slot has finished.

In this case, the branch destination address is saved in the stack.

7.3.6

PC Trace

1. Setting PCTE in BRCR to 1 enables PC traces. When branch (branch instruction, and interrupt

exception) is generated, the branch source address and branch destination address are stored in

BRSR and BRDR, respectively.

2. The values stored in BRSR and BRDR are as given below due to the kind of branch.

 If a branch occurs due to a branch instruction, the address of the branch instruction is saved

in BRSR and the address of the branch destination instruction is saved in BRDR.

 If a branch occurs due to an interrupt or exception, the value saved in stack due to

exception occurrence is saved in BRSR and the start address of the exception handling

routine is saved in BRDR.

3. BRSR and BRDR have four pairs of queue structures. The top of queues is read first when the

address stored in the PC trace register is read. BRSR and BRDR share the read pointer. Read

BRSR and BRDR in order, the queue only shifts after BRDR is read. After switching the

PCTE bit (in BRCR) off and on, the values in the queues are invalid.

SH7124 Datasheet(PDF) 158 Page - Renesas Technology Corp