SH7721 datasheet(183/1524 Pages) RENESAS

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Section 3 DSP Operating Unit

Rev. 3.00 Jan. 18, 2008 Page 121 of 1458

REJ09B0033-0300

• Conditional Operations and Data Transfer

Some instructions belonging to this class can be executed conditionally, as described earlier.

The specified condition is valid only for the B field of the instruction, and is not valid for data

transfer instructions for which a parallel specification is made. Examples are shown in figure

3.7.

DCT PADD X0,Y0,A0

MOVX.W @R4+,X0

MOVY.W A0,@R6+R9

When condition is True

Before execution:

After execution:

X0=H'33333333, Y0=H'55555555, A0=H'123456789A,

R4=H'00008000, R6=H'00005000, R9=H'00000004

(R4)=H'1111, (R6)=H'2222

X0=H'11110000, Y0=H'55555555, A0=H'0088888888,

R4=H'00008002, R6=H'00005004, R9=H'00000004

(R4)=H'1111, (R6)=H'3456

When condition is False

Before execution:

After execution:

X0=H'33333333, Y0=H'55555555, A0=H'123456789A,

R4=H'00008000, R6=H'00005000, R9=H'00000004

(R4)=H'1111, (R6)=H'2222

X0=H'11110000, Y0=H'55555555, A0=H'123456789A,

R4=H'00008002, R6=H'00005004, R9=H'00000004

(R4)=H'1111, (R6)=H'3456

Figure 3.7 Examples of Conditional Operations and Data Transfer Instructions

• Assignment of NOPX and NOPY Instruction Codes

When there is no data transfer instruction to be parallel-processed simultaneously with a DSP

operation instruction, an NOPX or NOPY instruction can be written as the data transfer

instruction, or the instruction can be omitted. The instruction code is the same whether an

NOPX or NOPY instruction is written or the instruction is omitted. Examples of NOPX and

NOPY instruction codes are shown in table 3.20.

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