HD6432670 Hitachi, HD6432670 Datasheet - Page 96

• Manufacturer Part Number: HD6432670
• Description: (HD64F267x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Register indirect with pre-decrement—@-ERn: The value 1, 2, or 4 is subtracted from an
address register (ERn) specified by the register field in the instruction code, and the result
becomes the address of a memory operand. The result is also stored in the address register. The
value subtracted is 1 for byte access, 2 for word transfer instruction, or 4 for longword transfer
instruction. For word or longword transfer instruction, the register value should be even.
2.7.5
The instruction code contains the absolute address of a memory operand. The absolute address
may be 8 bits long (@aa:8), 16 bits long (@aa:16), 24 bits long (@aa:24), or 32 bits long
(@aa:32). Table 2.12 indicates the accessible absolute address ranges.
To access data, the absolute address should be 8 bits (@aa:8), 16 bits (@aa:16), or 32 bits
(@aa:32) long. For an 8-bit absolute address, the upper 24 bits are all assumed to be 1 (H'FFFF).
For a 16-bit absolute address, the upper 16 bits are a sign extension. A 32-bit absolute address can
access the entire address space.
A 24-bit absolute address (@aa:24) indicates the address of a program instruction. The upper 8
bits are all assumed to be 0 (H'00).
Table 2.12 Absolute Address Access Ranges
Absolute Address
Data address
Program instruction
address
Note: Not available in this LSI.
2.7.6
The instruction code contains 8-bit (#xx:8), 16-bit (#xx:16), or 32-bit (#xx:32) immediate data as
an operand.
The ADDS, SUBS, INC, and DEC instructions contain immediate data implicitly. Some bit
manipulation instructions contain 3-bit immediate data in the instruction code, specifying a bit
number. The TRAPA instruction contains 2-bit immediate data in its instruction code, specifying a
vector address.
Rev. 2.0, 04/02, page 50 of 906
Absolute Address—@aa:8, @aa:16, @aa:24, or @aa:32
Immediate—#xx:8, #xx:16, or #xx:32
8 bits (@aa:8)
16 bits (@aa:16)
32 bits (@aa:32)
24 bits (@aa:24)
Normal Mode*
H'FF00 to H'FFFF
H'0000 to H'FFFF
Advanced Mode
H'FFFF00 to H'FFFFFF
H'000000 to H'007FFF,
H'FF8000 to H'FFFFFF
H'000000 to H'FFFFFF