SUBF3
Subtract Floating-Point Value, 3-Operand
13-230
Syntax
SUBF3
src2, src1, dst
Operation
src1 – src2
→
dst
Operands
src1 3-operand addressing modes (T):
0 0
register (R
n1, 0
≤
n1
≤
7)
0 1
indirect (
disp = 0, 1, IR0, IR1)
1 0
register (R
n1, 0
≤
n1
≤
7)
1 1
indirect (
disp = 0, 1, IR0, IR1)
src2 3-operand addressing modes (T):
0 0
register (R
n2, 0
≤
n2
≤
7)
0 1
register (R
n2, 0
≤
n2
≤
7)
1 0
indirect (
disp = 0, 1, IR0, IR1)
1 1
indirect (
disp = 0, 1, IR0, IR1)
dst register (Rn, 0
≤
n
≤
7)
Opcode
31
24 23
16
8 7
0
15
0 0 1
0 0
0
1
1
1
dst
T
src1
src2
Description
The difference between the
src1 and src2 operands is loaded into the dst reg-
ister. The
src1, src2, and dst 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