Effective Address Calculation - Hitachi HD6473867 Hardware Manual

8. Memory Indirect—@@aa:8: This mode can be used by the JMP and JSR instructions. The
second byte of the instruction code specifies an 8-bit absolute address. The word located at this
address contains the branch destination address.
The upper 8 bits of the absolute address are assumed to be 0 (H'00), so the address range is
from H'0000 to H'00FF (0 to 255). Note that with the H8/300L Series, the lower end of the
address area is also used as a vector area. See 3.3, Interrupts, for details on the vector area.
If an odd address is specified as a branch destination or as the operand address of a MOV.W
instruction, the least significant bit is regarded as 0, causing word access to be performed at the
address preceding the specified address. See 2.3.2, Memory Data Formats, for further information.

2.4.2 Effective Address Calculation

Table 2-2 shows how effective addresses are calculated in each of the addressing modes.
Arithmetic and logic instructions use register direct addressing (1). The ADD.B, ADDX, SUBX,
CMP.B, AND, OR, and XOR instructions can also use immediate addressing (6).
Data transfer instructions can use all addressing modes except program-counter relative (7) and
memory indirect (8).
Bit manipulation instructions can use register direct (1), register indirect (2), or 8-bit absolute
addressing (5) to specify the operand. Register indirect (1) (BSET, BCLR, BNOT, and BTST
instructions) or 3-bit immediate addressing (6) can be used independently to specify a bit position in
the operand.
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