S3F84B8_UM_REV 1.00
6 INSTRUCTION SET
6-43
6.3.30 INC — INCREMENT
INC
dst
Operation
: dst
dst + 1
The contents of the destination operand are incremented by one.
Flags
:
C
: Unaffected.
Z
: Set if the result is “0”; cleared otherwise.
S
: Set if the result is negative; cleared otherwise.
V
: Set if arithmetic overflow occurred; cleared otherwise.
D
: Unaffected.
H
: Unaffected.
Format
:
Bytes Cycles
Opcode
(Hex)
Addr Mode
dst
dst | opc
1
4
rE
r
r = 0 to F
opc
dst
2
4
20
R
4
21
IR
Examples
:
Given R0 = 1BH, register 00H = 0CH, and register 1BH = 0FH:
INC
R0
R0 = 1CH
INC 00H
Register 00H = 0DH
INC
@R0
R0 = 1BH, register 01H = 10H
In the first example, if destination working register R0 contains the value 1BH, the statement “INC
R0” leaves the value 1CH in the same register.
The next example shows the effect an INC instruction has on register 00H, assuming that it
contains the value 0CH.
In the third example, INC is used in Indirect Register (IR) addressing mode to increment the value
of register 1BH from 0FH to 10H.