HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 140

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

Addressing Mode for Double Data Transfer Instructions: The double data transfer instructions
supports the following three addressing modes.
• Non-update address register addressing
• Increment address register addressing
• Addition index register addressing
When using X/Y memory addressing, bit 0 of the address pointer is invalid. Accordingly, bit 0 of
the address pointer and index register must be cleared to 0 in X/Y memory addressing. If 1 is
written to the bit, correct operation cannot be guaranteed.
When accessing X and Y memories using the X and Y buses, the upper word of Ax and Ay are
ignored. The result of Ay + 2 or Ay + Iy is stored in the lower word of Ay, while the upper word
retains its original value. The Ax + 2 and Ax + Ix operations are executed in longword (32 bits)
and the upper word may be changed according to the result.
Addressing Mode for Single Data Transfer Instructions: The following four kinds of
addressing can be used with single data transfer instructions.
• Non-update address register addressing
• Increment address register addressing:
• Addition index register addressing:
• Decrement address register addressing:
In single data transfer instructions, all bits in 32-bit address are valid.
Rev. 1.00, 02/04, page 102 of 804
The Ax and Ay registers are address pointers. They are not updated.
The Ax and Ay registers are address pointers. After a data transfer, they are each incremented
by 2 (post- increment).
The Ax and Ay registers are address pointers. After a data transfer, the value of the Ix or Iy
register is added to each (post-increment). The double data transfer instructions do not supports
decrement addressing mode. To perform decrementing, –2 is set in the index register and
addition index register addressing is specified.
The As register is an address pointer. An access to @As is performed but As is not updated.
The As register is an address pointer. After an access to @As, the As register is incremented
by 2 or 4 (post-increment).
The As register is an address pointer. After an access to @As, the value of the Is register is
added to the As register (post-increment).
The As register is an address pointer. Before a data transfer, –2 or –4 is added to the As
register (i.e. 2 or 4 is subtracted) (pre-decrement).