SH7708 datasheet(155/633 Pages) RENESAS

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7.3.4

Saved Program Counter (PC) Value

1. When instruction fetch (pre-execution) is set as break condition

The program counter (PC) value saved in the SPC in user break interrupt handling is the

address of the instruction for which the break condition matched. In this case, the fetched

instruction is not executed, due to the user break interrupt generated prior to its execution. In

the fetch cycle of an instruction located in the delay slot of a delayed branch instruction, a

break is generated before the branch, so that the SPC value indicates the delayed branch

instruction.

2. When instruction fetch (post-execution) is set as break condition

The program counter (PC) value saved in the SPC in user break interrupt processing is the

address of the next instruction to be executed after the instruction for which the break

condition matched. In this case, the fetched instruction is executed, and a user break trap

occurs before execution of the next instruction. When a delayed branch instruction is

designated, the delay slot instruction is executed and a user break occurs before execution of

the instruction at the branch destination. In this case, the PC value saved in the SPC is the

address of the branch destination instruction.

3. When data access (address only) is set as break condition

The value saved is the address of the next instruction to be executed after the instruction for

which the condition matched. The condition-matching instruction is executed, and a user break

trap occurs before execution of the next instruction.

4. When data access (address + data ) is set as break condition

The value saved is the start address of the next instruction after the instruction for which

execution has been completed when user break trap processing is initiated. When a data value

is set as a break condition, the point at which the break is to be made cannot be specified. A

break is executed before execution of the instruction fetched around the time of the break data

access.

SH7708 Datasheet(PDF) 155 Page - Renesas Technology Corp