HD6432646 Hitachi, HD6432646 Datasheet - Page 77

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

2.5.2
Figure 2-11 shows the data formats in memory. The CPU can access word data and longword data
in memory, but word or longword data must begin at an even address. If an attempt is made to
access word or longword data at an odd address, no address error occurs but the least significant
bit of the address is regarded as 0, so the access starts at the preceding address. This also applies to
instruction fetches.
When ER7 is used as an address register to access the stack, the operand size should be word size
or longword size.
Memory Data Formats
Data Type
1-bit data
Byte data
Word data
Longword data
Figure 2-11 Memory Data Formats
Address 2M + 1
Address 2N + 1
Address 2N + 2
Address 2N + 3
Address 2M
Address 2N
Address
Address L
Address L
MSB
MSB
MSB
7
7
6
Data Format
5
4
3
2
1
LSB
LSB
LSB
0
0
43