SH7136 datasheet(173/1160 Pages) RENESAS

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Section 7 User Break Controller (UBC)

Rev. 2.00 Sep. 10, 2008 Page 147 of 1130

REJ09B0402-0200

When this kind of break occurs at a delayed branch instruction or its delay slot, the break may

not actually take place until the processing jumps to the first instruction at the branch

destination.

7.4.4

Sequential Break

1. By setting the SEQ bit in BRCR to 1, the sequential break is issued when a channel B break

condition matches after a channel A break condition matches. A user break is not generated

even if a channel B break condition matches before a channel A break condition matches.

When channels A and B conditions match at the same time, the sequential break is not issued.

To clear the channel A condition match when a channel A condition match has occurred but a

channel B condition match has not yet occurred when a sequential break has been specified,

clear the SEQ bit in BRCR and channel A condition match flag to 0 by writing a 0 to them.

2. In sequential break specification, the L or I bus can be selected and the execution times break

condition can be also specified. For example, when the execution times break condition is

specified, the break condition is satisfied when a channel B condition matches with BETR =

H'0001 after a channel A condition has matched.

7.4.5

Value of Saved Program Counter

When a user break occurs, the address of the instruction from where execution is to be resumed is

saved in the stack, and the exception handling state is entered. If the L bus is specified as the break

condition, the instruction at which the user break should occur can be clearly determined (except

for when data is included in the break condition). If the I bus is specified as a break condition, the

instruction at which the user break should occur cannot be clearly determined.

1. When instruction fetch (before instruction execution) is specified as a break condition:

The address of the instruction that matched the break condition is saved in the stack. The

instruction that matched the condition is not executed, and the user break occurs before it.

However when a delay slot instruction matches the condition, the address of the delayed

branch instruction is saved in the stack.

2. When instruction fetch (after instruction execution) is specified as a break condition:

The address of the instruction following the instruction that matched the break condition is

saved in the stack. The instruction that matches the condition is executed, and the break occurs

before the next instruction is executed. However when a delayed branch instruction or delay

slot matches the condition, these instructions are executed, and the branch destination address

is saved in the stack.

SH7136 Datasheet(PDF) 173 Page - Renesas Technology Corp