SH7144 Datasheet, PDF (58/773 Pages) Renesas Technology Corp – Hitachi SuperH RISC engine

Address 2n
Address 4n
Address m + 1
Address m + 3
Address m
Address m + 2
31
23
15
7
0
Byte
Byte
Byte
Byte
Word
Word
Longword
Figure 2.3 Data Formats in Memory
2.3.3 Immediate Data Format
Byte (8 bit) immediate data resides in an instruction code. Immediate data accessed by the MOV,
ADD, and CMP/EQ instructions is sign-extended and handled in registers as longword data.
Immediate data accessed by the TST, AND, OR, and XOR instructions is zero-extended and
handled as longword data. Consequently, AND instructions with immediate data always clear the
upper 24 bits of the destination register.
Word or longword immediate data is not located in the instruction code, but instead is stored in a
memory table. An immediate data transfer instruction (MOV) accesses the memory table using the
PC relative addressing mode with displacement.
2.4 Instruction Features
2.4.1 RISC-Type Instruction Set
All instructions are RISC type. This section details their functions.
16-Bit Fixed Length: All instructions are 16 bits long, increasing program code efficiency.
One Instruction per State: The microcomputer can execute basic instructions in one state using
the pipeline system. One state is 25 ns at 40 MHz.
Data Length: Longword is the standard data length for all operations. Memory can be accessed in
bytes, words, or longwords. Byte or word data accessed from memory is sign-extended and
handled as longword data. Immediate data is sign-extended for arithmetic operations or zero-
extended for logic operations. It also is handled as longword data.
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