HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 129

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

3.3.2
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 that are shown in table 3.8. 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.
• Example 1: Repeat loop consisting of 4 or more instructions
RptStart: instr1
RptEnd:
Extended Repeat Control Instructions
LDRS RptStart
LDRE RptEnd
LDRC #4
instr0
... ...
... ...
instr(N-3)
instr(N-2)
instr(N-1)
instrN
;
;
to the RE register
; Sets repeat start instruction address
; Sets repeat end instruction address
; Sets the number of repetitions (4) to
; At least one instruction is required
; [Repeat start instruction]
;
;
; [Repeat detection instruction]
; [Repeat end instruction]
repeat end instruction is regarded as a
to the RS register
the RC[11:0] bits of the SR register
from LDRC instruction to [Repeat start
instruction]
An instruction three instructions prior to the
repeat detection instruction.
Rev. 1.00, 02/04, page 91 of 804