SH7065 datasheet(55/941 Pages) RENESAS

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Section 2 CPU

Rev. 5.00 Sep 11, 2006 page 33 of 916

REJ09B0332-0500

2.2.3

Immediate Data Formats

Byte immediate data is placed inside the instruction code.

With the MOV, ADD, and CMP/EQ instructions, immediate data is sign-extended and a longword

operation is performed with a register. With the TST, AND, OR, and XOR instructions, on the

other hand, a longword operation is performed after zero-extending the immediate data. Therefore,

when immediate data is used with an AND instruction, the upper 24 bits of the destination register

are always cleared.

Word and longword immediate data should be placed in a table in memory, not inside the

instruction code. The table in memory should be referenced with an immediate data transfer

instruction (MOV) using PC relative addressing mode with displacement.

2.2.4

DSP Type Data Formats

The SH7065 has three different data formats for instructions: fixed-point data format, integer data

format, and logical data format.

In the DSP type fixed-point data format, there is a binary point between bit 31 and bit 30. There

are three kinds of format—with guard bits, without guard bits, and multiplication input—each

with a different valid bit length and range of expressable values.

In the DSP type integer data format, there is a binary point between bit 16 and bit 15. There are

three kinds of format—with guard bits, without guard bits, and shift amount—each with a

different valid bit length and range of expressable values. The shift amount for an arithmetic shift

(PSHA) is a 7-bit area, and values from –64 to +63 can be expressed, but only values from –32 to

+32 are actually valid. Similarly, the shift amount for a logical shift (PSHL) is a 6-bit area, but

only values from –16 to +16 are actually valid.

There is no radix point in the DSP type logical data format.

The data format and valid data length are determined by the DSP register.

The three DSP type data formats and the position of the binary point in each are shown in figure

2.7, together with a SuperH type data format for reference.

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