Absolute Value of Accumulator
ABS
7-21
Assembly Language Instructions
Syntax
ABS
Operands
None
Opcode
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0
0
0
0
0
0
0
0
0
1
1
1
1
1
0
1
Execution
Increment PC, then ...
|(ACC)|
→
ACC; 0
→
C
Status Bits
Affected by
Affects
OVM
C and OV
This instruction is not affected by SXM
Description
If the contents of the accumulator are greater than or equal to zero, the accu-
mulator is unchanged by the execution of ABS. If the contents of the accumula-
tor are less than zero, the accumulator is replaced by its 2s-complement value.
The carry bit (C) on the ’C2xx is always reset to zero by the execution of this
instruction.
Note that 8000 0000h is a special case. When the overflow mode is not set
(OVM = 0), the ABS of 8000 0000h is 8000 0000h. When the overflow mode
is set (OVM = 1), the ABS of 8000 0000h is 7FFF FFFFh. In either case, the
OV status bit is set.
Words
1
Cycles for a Single ABS Instruction
ROM
DARAM
SARAM
External
1
1
1
1+p
Cycles for a Repeat (RPT) Execution of an ABS Instruction
ROM
DARAM
SARAM
External
n
n
n
n+p
Cycles