SUBF
Subtract Floating-Point Value
13-228
Syntax
SUBF
src, dst
Operation
dst – src
→
dst
Operands
src general addressing modes (G):
0 0
register (R
n, 0
≤
n
≤
7)
0 1
direct
1 0
indirect (disp = 0–255, IR0, IR1)
1 1
immediate
dst register (Rn, 0
≤
n
≤
7)
Opcode
31
24 23
16
8 7
0
15
0 0 0 1 0
1
1
1
1
dst
G
src
Description
The difference between
the dst operand and the src operand is loaded into the
dst register. The dst and src operands are assumed to be floating-point num-
bers.
Cycles
1
Status Bits
These condition flags are modified only if the destination register is R7 – R0.
LUF
1 if a floating-point underflow occurs; unchanged otherwise
LV
1 if a floating-point overflow occurs; unchanged otherwise
UF
1 if a floating-point underflow occurs; 0 otherwise
N
1 if a negative result is generated; 0 otherwise
Z
1 if a 0 result is generated; 0 otherwise
V
1 if a floating-point overflow occurs; 0 otherwise
C
Unaffected
OVM
Operation is not affected by OVM bit value.
Mode Bit