HD6417618 RENESAS [Renesas Technology Corp], HD6417618 Datasheet - Page 56

• Manufacturer Part Number: HD6417618
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7618 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 2 CPU
2.3
2.3.1
The size of register operands is always longwords (32 bits). When loading byte (8 bits) or word
(16 bits) data in memory into a register, the data is sign-extended to longword and stored in the
register.
2.3.2
Memory data formats are classified into byte, word, and longword.
Byte data can be accessed from any address. If word data starting from boundary other than 2n or
longword data starting from a boundary other than 4n is accessed, an address error will occur. In
such cases, the data accessed cannot be guaranteed. See figure 2.3.
Either big endian and little endian formats can be selected according to the mode pin setting at a
reset. For details on mode pin settings, see section 7, Bus State Controller (BSC).
Rev. 6.00 Jun. 12, 2007 Page 24 of 610
REJ09B0131-0600
Address A
Address A + 4
Address A + 8
Data Formats
Register Data Format
Memory Data Formats
Address A
31
Byte 0
Word 0
Address A + 1
23
Byte 1
Big endian
Longword
Address A + 2
31
15
Figure 2.3 Memory Data Format
Figure 2.2 Register Data Format
Byte 2
Address A + 3
Word 1
7
Byte 3
0
Longword
Address A + 11
31
Byte 3
Address A + 10
Word 1
23
Byte 2
Little endian
Longword
Address A + 9
0
15
Byte 1
Address A + 8
Word 0
7
Byte 0
0
Address A + 8
Address A + 4
Address A