HD6417144 RENESAS [Renesas Technology Corp], HD6417144 Datasheet - Page 155

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

7.5
7.5.1
Two instructions may be simultaneously fetched in instruction fetch operation. Once a break
condition is set on the latter of these two instructions, a user break interrupt will occur before the
latter instruction, even though the contents of the UBC registers are modified to change the break
conditions immediately after the fetching of the former instruction.
7.5.2
When a conditional branch instruction or TRAPA instruction causes a branch, the order of
instruction fetching and execution is as follows:
1. When branching with a conditional branch instruction: BT and BF instructions
2. When branching with a delayed conditional branch instruction: BT/S and BF/S instructions
Thus, when a conditional branch instruction or TRAPA instruction causes a branch, the branch
destination instruction will be fetched after an overrun fetch of the next instruction or the
instruction after the next. However, as the instruction that is the object of the break does not break
until fetching and execution of the instruction have been confirmed, the overrun fetches described
above do not become objects of a break.
If data accesses are also included in break conditions besides instruction fetch, a break will occur
because the instruction overrun fetch is also regarded as satisfying the data break condition.
When branching with a TRAPA instruction:
a. Instruction fetch order
b. Instruction execution order
a. Instruction fetch order
b. Instruction execution order
Branch instruction fetch → next instruction overrun fetch → overrun fetch of instruction
after the next → branch destination instruction fetch
Branch instruction execution → branch destination instruction execution
Branch instruction fetch → next instruction fetch (delay slot) → overrun fetch of
instruction after the next → branch destination instruction fetch
Branch instruction execution → delay slot instruction execution → branch destination
instruction execution
Usage Notes
Simultaneous Fetching of Two Instructions
Instruction Fetches at Branches
Rev.4.00 Mar. 27, 2008 Page 111 of 882
TRAPA instruction
7. User Break Controller (UBC)
REJ09B0108-0400