DP805x Instructions set details
- 23 -
3.6.
CJNE
Instruction:
Function:
CJNE <dest-byte >, < src-byte >, rel
Compare and jump if not equal.
Description: CJNE compares the magnitudes of the first two operands, and
branches if their values are not equal. The branch destination is
computed by adding the signed relative displacement in the last
instruction byte to the PC, after incrementing the PC to the start of the
next instruction. The carry flag is set if the unsigned integer value of
<dest-byte> is less than the unsigned integer value of <src-byte>;
otherwise, the carry is cleared. Neither operand is affected. The first two
operands allow four addressing mode combinations: the accumulator
may be compared with any directly addressed byte or immediate data,
and any indirect RAM location or working register can be compared with
an immediate constant.
3.6.1. CJNE A, DIRECT, REL
Operation:
(PC) ← (PC) + 3
if (A) < > (direct) then
(PC) ← (PC) + relative offset
if (A) < (direct) then
(C) ← 1
else
(C) ← 0
Bytes:
Cycles:
3
5
Encoding:
1
0
1
1
0
1
0
1
direct address
relative address
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