SH7713 datasheet(128/904 Pages) RENESAS

128 / 904 page

Section 3 DSP Operating Unit

Rev.1.50 Aug. 30, 2006 Page 88 of 860

REJ09B0288-0150

The CPU always executes a program with comparing the repeat end register (RE) and the

program counter (PC). If the PC matches the RE while the RC[11:0] bits of the SR register are

other than 0, the repeat control function is initiated.

 If RC ≥ 2, a control is passed to a repeat start instruction after a repeat end instruction has

been executed. The RC is decremented by 1 at the completion of the repeat end instruction.

In this case, restrictions 1 to 6 are also applied.

 If RC == 1, the RC is decremented to 0 at the completion of the repeat end instruction and

a control is passed to the subsequent instruction. In this case, restrictions 1 to 6 are also

applied.

 If RC == 0, the repeat control function is not initiated even if a repeat detection instruction

is executed. The repeat loop is executed once as normal instructions and a control is not be

passed to a repeat start instruction even if a repeat end instruction is executed.

3.3.2

Extended Repeat Control Instructions

In the repeat control function described in section 3.3.1, Repeat Control Instructions, there are

some restrictions. To reduce these restrictions, this LSI supports the extended repeat instructions

to extend the repeat control function. These extended repeat control instructions were not

supported in the conventional SH-DSP. To keep compatibility with the conventional SH-DSP, use

the conventional repeat control instructions called compatible repeat control instructions.

Program Examples Using the Extended Repeat Control Instructions: Examples of repeat loop

programs using the extended repeat control instructions are shown below.

SH7713 Datasheet(PDF) 128 Page - Renesas Technology Corp