Services and Modeling for Embedded Software Development
3.4.3.
SUB
: Unsigned Subtract
Encoding (format 1):
0
0
0
0
0
1
0
d
2
d
1
d
0
a
2
a
1
a
0
b
2
b
1
b
0
Syntax:
SUB
R
d
,
R
a
,
R
b
Constraints:
a ≤ 7
b ≤ 7
d ≤ 7
Outcome:
R
d
← R
a
- R
b
carry ← ( R
b
> R
a
) ? 1 : 0
PC ← PC + 1