HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 55

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

1 Register Direct—Rn: The register field of the instruction code specifies an 8-, 16-, or 32-bit
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 Register Indirect—@ERn: The register field of the instruction code specifies an address
register (ERn), the lower 24 bits of which contain the address of the operand.
3 Register Indirect with Displacement—@(d:16, ERn) or @(d:24, ERn): A 16-bit or 24-bit
displacement contained in the instruction code is added to the contents of an address register
(ERn) specified by the register field of the instruction, and the lower 24 bits of the sum specify the
address of a memory operand. A 16-bit displacement is sign-extended when added.
4 Register Indirect with Post-Increment or Pre-Decrement—@ERn+ or @–ERn:
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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.
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.
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