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Section 2 CPU
Page 56 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
2.3 Instruction Features
2.3.1 RISC-Type Instruction Set
Instructions are RISC type. This section details their functions.
(1) 16-Bit Fixed-Length Instructions
Basic instructions have a fixed length of 16 bits, improving program code efficiency.
(2) 32-Bit Fixed-Length Instructions
The SH-2A additionally features 32-bit fixed-length instructions, improving performance and ease
of use.
(3) One Instruction per State
Each basic instruction can be executed in one cycle using the pipeline system.
(4) Data Length
Longword is the standard data length for all operations. Memory can be accessed in bytes, words,
or longwords. Byte or word data in memory is sign-extended and handled as longword data.
Immediate data is sign-extended for arithmetic operations or zero-extended for logic operations. It
is also handled as longword data.
Table 2.2 Sign Extension of Word Data
SH2-A CPU Description Example of Other CPU
MOV.W @(disp,PC),R1
ADD R1,R0
.........
.DATA.W H'1234
Data is sign-extended to 32
bits, and R1 becomes
H'00001234. It is next
operated upon by an ADD
instruction.
ADD.W #H'1234,R0
Note: @(disp, PC) accesses the immediate data.
(5) Load-Store Architecture
Basic operations are executed between registers. For operations that involve memory access, data
is loaded to the registers and executed (load-store architecture). Instructions such as AND that
manipulate bits, however, are executed directly in memory.