DL205 User Manual, 4th Edition, Rev. B
5–93
Chapter 5: Standard RLL Instructions - Math
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
Subtract Real (SUBR)
The Subtract Real is a 32-bit instruction that subtracts a real
number, which is either two consecutive V-memory locations or
a 32-bit constant, from a real number in the accumulator. The
result is a 32-bit real number that resides in the accumulator.
Both numbers must be Real data type (IEEE floating point
format).
NOTE:
Status flags are valid only until another instruction uses the same flag.
NOTE:
The current HPP does not support real number entry with automatic conversion to the 32-bit IEEE
format. You must use
Direct
SOFT for this feature.
SUBR
A aaa
ý
ý
þ
þ
230
240
2
5
0
-1
2
6
0
nd
ar
d
R
LL
st
ru
ct
io
ns
LDR
R22.0
X1
SUBR
R15.0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0 1 1 1 0 0 0 0 0
8 4 2 1 8 4 2 1 8 4 2 1 8 4 2 1
8 4 2 1 8 4 2 1 8 4 2 1 8 4 2 1
Acc.
4 0 E 0
0 0 0 0
V1400
V1401
Real Value
OUTD
V1400
Implies 2 (exp 2)
129 -- 127 = 2
(Hex number)
Mantissa (23 bits)
Sign Bit
4 1 B 0
0 0 0 0
0 0 0 0
4 1 B 0
(SUBR)
(Accumulator)
4 1 7 0
0 0 0 0
_
0 0 0 0
4 0 E 0
Acc.
2 2 (decimal)
_ 1 5
7
1.11 x 2 (exp 2) = 111. binary= 7 decimal
128 + 1 = 129
Exponent (8 bits)
Direct
SO
F
T
Load the real number
22.0 into the accumulator.
Subtract the real number
15.0 from the accumulator
contents, which is in real
number format.
Copy the result in the
accumulator to V1400
and V1401.
Discrete Bit Flags
Description
SP63
On when the result of the instruction causes the value in the accumulator to be zero.
SP70
On anytime the value in the accumulator is negative.
SP71
On anytime the V-memory specified by a pointer (P) is not valid.
SP72
On anytime the value in the accumulator is an invalid floating point number.
SP73
On when a signed addition or subtraction results in an incorrect sign bit.
SP74
On anytime a floating point math operation results in an underflow error.
SP75
On when a real number instruction is executed and a non-real number was encountered.
Operand Data Type
DL250-1 Range
DL260 Range
A
aaa
aaa
V-memory V
All. (See page 3-55)
All. (See page 3-56)
Pointer P All V-memory (See page 3-55) All V-memory (See page 3-56)
Constant R
-3.038 to
+ 3.038
-3.038 to
+ 3.038
DS
Used
HPP
N/A