SH7721 datasheet(302/1524 Pages) RENESAS

302 / 1524 page

Section 7 Exception Handling

Rev. 3.00 Jan. 18, 2008 Page 240 of 1458

REJ09B0033-0300

Table 7.5

Instruction Where a Specific Exception Occurs When a Memory Access

Exception Occurs in Repeat Control (SR.RC[11:0]

≥1)

Number of Instructions in a Repeat Loop

Instruction Where an

Exception Occurs

4 or Greater

RptDtct



RptDtct1

Instruction/data

access

Instruction/data

access

Instruction/data

access

Instruction/data

access

RptDtct2



Instruction/data

access

Instruction/data

access

Instruction/data

access

RptDtct3



Instruction/data

access

Instruction/data

access

Note:

The following labels are used here.

RptDtct:

Repeat detection instruction address

RptDtct1: Instruction address immediately after the repeat detect instruction

RptDtct2: Second instruction address from the repeat detect instruction

RptDtct3: Third instruction address from the repeat detect instruction

(5)

MMU Exception in Repeat Control Period

If an MMU exception occurs in the repeat control period, a specific exception code is generated as

well as a CPU address error. For a TLB miss exception, TLB invalid exception, and initial page

write exception, an exception code (H'070) indicating the repeat loop period is specified in the

EXPEVT. For a TLB protection exception, an exception code (H'0D0) is specified in the

EXPEVT. In a TLB miss exception, vector offset is specified as H'00000100.

An instruction where an exception occurs and the SPC value to be saved are the same as those for

the CPU address error.

After this exception processing, the repeat control cannot be returned correctly. To execute a

repeat loop correctly, care must be taken not to generate an MMU related exception in the repeat

control period.

Note:

In a repeat loop consisting of one to three instructions, some restrictions apply to repeat

detection instructions and all the remaining instructions. In a repeat loop consisting of four

or more instructions, restrictions apply to only the three instructions that include a repeat

end instruction. The restriction occurs when SR.RC[11:0]

≥ 1.

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