HD64F3048VTF8 Datasheet, PDF (84/903 Pages) Renesas Technology Corp – Hardware Manual Renesas 8-Bit Single-Chip

Section 2 CPU
4. Register Indirect with Post-Increment or Pre-Decrement—@ERn+ or @–ERn
• Register indirect with post-increment—@ERn+
The register field of the instruction code specifies an address register (ERn) the lower 24 bits
of which contain the address of a memory operand. After the operand is accessed, 1, 2, or 4 is
added to the address register contents (32 bits) and the sum is stored in the address register.
The value added is 1 for byte access, 2 for word access, or 4 for longword access. For word or
longword access, the register value should be even.
• 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 lower 24 bits of the result become 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 access, or 4 for longword access. For word or longword access, the resulting
register value should be even.
5. Absolute Address—@aa:8, @aa:16, or @aa:24
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), or 24 bits long (@aa:24). For an 8-bit absolute
address, the upper 16 bits are all assumed to be 1 (H'FFFF). For a 16-bit absolute address the
upper 8 bits are a sign extension. A 24-bit absolute address can access the entire address space.
Table 2.12 indicates the accessible address ranges.
Table 2.12 Absolute Address Access Ranges
Absolute Address
8 bits (@aa:8)
16 bits (@aa:16)
24 bits (@aa:24)
1-Mbyte Modes
H'FFF00 to H'FFFFF
(1048320 to 1048575)
H'00000 to H'07FFF,
H'F8000 to H'FFFFF
(0 to 32767, 1015808 to 1048575)
H'00000 to H'FFFFF
(0 to 1048575)
16-Mbyte Modes
H'FFFF00 to H'FFFFFF
(16776960 to 16777215)
H'000000 to H'007FFF,
H'FF8000 to H'FFFFFF
(0 to 32767, 16744448 to 16777215)
H'000000 to H'FFFFFF
(0 to 16777215)
Rev. 3.00 Sep 27, 2006 page 56 of 872
REJ09B0325-0300