HD6417641 RENESAS [Renesas Technology Corp], HD6417641 Datasheet - Page 175

• Manufacturer Part Number: HD6417641
• Manufacturer: RENESAS [Renesas Technology Corp]

#imm is 8 bits while RC is 12 bits. Therefore, to set more than 256 into RC, use Rm. A sample
program is shown below.
In this implementation, there are some restrictions to use this repeat control function as follows:
1. There must be at least one instruction between SETRC and the first instruction in a repeat
2. LDRS and LDRE must be executed before SETRC.
3. In a case that the repeat loop has four or more instructions in it, stall cycles are necessary
4. If a repeat loop has less than four instructions in it, it cannot have any branch instructions
Table 3.15 Address Value to be Stored into SPC (1)
Condition
RC ≥ 2
RC = 1
; instr1–5 executes repeatedly
RptStart:
RptEnd3:
RptEnd:
loop.
according to the pipeline state at execution.
(BRA, BSR, BT, BF, BT/S, BF/S, BSRF, RTS, BRAF, RTE, JSR and JMP), repeat control
instructions (SETRC, LDRS and LDRE), load instructions for SR, RS, RE, and a TRAPA
instruction in it. If these instructions are executed, a general invalid instruction exception
handling starts, and a certain address value shown in table 3.15 is stored into SPC.
LDRS
LDRE
SETRC
instr0;
instr1;
instr2;
instr3;
instr4;
instr5;
instr6;
Location
Any
Any
RptStart;
RptEnd3+4;
#imm;
RC = #imm
Address to be Pushed
RptStart
Address of the illegal instruction
Rev. 4.00 Sep. 14, 2005 Page 125 of 982
Section 3 DSP Operation
REJ09B0023-0400