Datasheet

Section 2 CPU
Page 74 of 1408 R01UH0309EJ0500 Rev. 5.00
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
2.7 Addressing Modes and Effective Address Calculation
The H8S/2600 CPU supports the eight addressing modes listed in table 2.11. The usable address
modes are different in each instruction.
Arithmetic and logic instructions can use the register direct and immediate modes. Data transfer
instructions can use all addressing modes except program-counter relative and memory indirect.
Bit manipulation instructions use register direct, register indirect, or absolute addressing mode to
specify an operand, and register direct (BSET, BCLR, BNOT, and BTST instructions) or
immediate (3-bit) addressing mode to specify a bit number in the operand.
Table 2.11 Addressing Modes
No. Addressing Mode Symbol
1 Register direct Rn
2 Register indirect @ERn
3 Register indirect with displacement @(d:16,ERn)/@(d:32,ERn)
4 Register indirect with post-increment
Register indirect with pre-decrement
@ERn+
@–ERn
5 Absolute address @aa:8/@aa:16/@aa:24/@aa:32
6 Immediate #xx:8/#xx:16/#xx:32
7 Program-counter relative @(d:8,PC)/@(d:16,PC)
8 Memory indirect @@aa:8
2.7.1 Register Direct—Rn
The register field of the instruction code specifies an 8-, 16-, or 32-bit general register containing
the operand. R0H to R7H and R0L to R7L can be specified as 8-bit registers. R0 to R7 and E0 to
E7 can be specified as 16-bit registers. ER0 to ER7 can be specified as 32-bit registers.
2.7.2 Register Indirect—@ERn
The register field of the instruction code specifies an address register (ERn) which contains the
address of the operand on memory. If the address is a program instruction address, the lower 24
bits are valid and the upper 8 bits are all assumed to be 0 (H'00).