RPTB
Repeat Block
13-210
Example
RPTB 127h
Before Instruction
After Instruction
PC
0123
PC
0124
RE
0
RE
127
RS
0
RS
124
ST
0
ST
100
LUF
0
LUF
0
LV
0
LV
0
UF
0
UF
0
N
0
N
0
Z
0
Z
0
V
0
V
0
C
0
C
0
Because the block-repeat modes modify the program counter, no
other instruction can modify the program counter at the same time.
The following two rules apply:
Rule 1: The last instruction in the block (or the only instruction in a
block of size 1) cannot be a B
cond, BR, DBcond, CALL,
CALL
cond, TRAPcond, RETIcond, RETScond, IDLE, IDLE2,
RPTB, or RPTS. Example 7–3 on page 7-6 shows an
incorrectly placed standard branch.
Rule 2: None of the last four instructions at the bottom of the block
(or the only instruction in a block of size 1) can be a
B
condD, BRD, or DBcondD. Example 7–4 on page 7-7
shows an incorrectly placed delayed branch.
If either rule is violated, the PC will be undefined.