SH7243 datasheet(222/1726 Pages) RENESAS

222 / 1726 page

Section 7 User Break Controller (UBC)

Rev. 1.00 Jun. 26, 2008 Page 192 of 1692

REJ09B0393-0100

7.4.4

Value of Saved Program Counter

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

saved to the stack, and the exception handling state is entered. If the C bus (FAB)/instruction fetch

cycle is specified as a break condition, the instruction at which the break should occur can be

uniquely determined. If the C bus/data access cycle or I bus/data access cycle is specified as a

break condition, the instruction at which the break should occur cannot be uniquely determined.

1. When C bus (FAB)/instruction fetch (before instruction execution) is specified as a break

condition:

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

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

when a delay slot instruction matches the condition, the instruction is executed, and the branch

destination address is saved to the stack.

2. When C bus (FAB)/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 to 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, the instruction is executed, and the branch destination address is

saved to the stack.

3. When C bus/data access cycle or I bus/data access cycle is specified as a break condition:

The address after executing several instructions of the instruction that matched the break

condition is saved to the stack.

SH7243 Datasheet(PDF) 222 Page - Renesas Technology Corp