r5s72060w200fpv Renesas Electronics Corporation., r5s72060w200fpv Datasheet - Page 61

• Manufacturer Part Number: r5s72060w200fpv
• Description: 32-bit Risc Microcomputer Superhtm Risc Engine Family / Sh7200 Series
• Manufacturer: Renesas Electronics Corporation.

(6)
With the exception of some instructions, unconditional branch instructions, etc., are executed as
delayed branch instructions. With a delayed branch instruction, the branch is taken after execution
of the instruction immediately following the delayed branch instruction. This reduces disturbance
of the pipeline control when a branch is taken.
In a delayed branch, the actual branch operation occurs after execution of the slot instruction.
However, instruction execution such as register updating excluding the actual branch operation, is
performed in the order of delayed branch instruction → delay slot instruction. For example, even
though the contents of the register holding the branch destination address are changed in the delay
slot, the branch destination address remains as the register contents prior to the change.
Table 2.3
(7)
The SH-2A additionally features unconditional branch instructions in which a delay slot
instruction is not executed. This eliminates unnecessary NOP instructions, and so reduces the code
size.
(8)
16-bit × 16-bit → 32-bit multiply operations are executed in one to two cycles. 16-bit × 16-bit +
64-bit → 64-bit multiply-and-accumulate operations are executed in two to three cycles. 32-bit ×
32-bit → 64-bit multiply and 32-bit × 32-bit + 64-bit → 64-bit multiply-and-accumulate
operations are executed in two to four cycles.
(9)
The T bit in the status register (SR) changes according to the result of the comparison. Whether a
conditional branch is taken or not taken depends upon the T bit condition (true/false). The number
of instructions that change the T bit is kept to a minimum to improve the processing speed.
SH-2A CPU
BRA
ADD
Delayed Branch Instructions
Unconditional Branch Instructions with No Delay Slot
Multiply/Multiply-and-Accumulate Operations
T Bit
TRGET
R1,R0
Delayed Branch Instructions
Executes the ADD before
branching to TRGET.
Description
Rev. 2.00 Dec. 09, 2005 Page 37 of 1152
Example of Other CPU
ADD.W
BRA
R1,R0
TRGET
REJ09B0191-0200
Section 2 CPU