SH7616 datasheet(84/935 Pages) RENESAS

84 / 935 page

Section 2 CPU

Rev. 2.00 Mar 09, 2006 page 58 of 906

REJ09B0292-0200

Single Data Addressing: Among the DSP instructions, the single data transfer instructions

(MOVS.W and MOVS.L) are used to either load data into DSP registers or to store it from them.

With these instructions, the registers R2 to R5 are used as address registers (As) for the single data

transfers.

The four following data addressing instructions exist for single data transfer instructions.

1. Non-updated address registers: The As registers are address pointers. They are not updated.

2. Add index registers: The As registers are address pointers. The Is register values are added to

them after the data transfer (post-update).

3. Increment address registers: The As registers are address pointers. The value +2 or +4 is added

after the data transfer (post-update).

4. Decrement address registers: The As registers are address pointers. The value –2 or –4 is added

(+2 or +4 is subtracted) before the data transfer (pre-update).

The address pointer (As) uses the R8 register as an index register (Is).

Figure 2.10 shows the single data transfer addressing.

ALU

R8[Is]

R4[As]

R5[As]

+2/+4 (INC)

+0 (No update)

Note: There are four addressing methods (no update, index register addition (Is),

increment, and decrement). Index register addition and increment are

post-updating methods. Decrement is a pre-updating method.

R3[As]

R2[As]

–2/–4 (DEC)

MAB

CAB

Figure 2.10 Single Data Transfer Addressing

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