Math Instructions; Add, Subtract, Multiply, And Divide Instructions - Siemens SIMATIC S7-200 System Manual

S7-200 Programmable Controller System Manual

Math Instructions

Add, Subtract, Multiply, and Divide
Instructions
Add
IN1 + IN2 = OUT
FBD
IN1 + OUT = OUT
The Add Integer (+I) or Subtract Integer (--I) instructions add
or subtract two 16-bit integers to produce a 16-bit result. The
Add Double Integer (+D) or Subtract Double Integer (--D)
instructions add or subtract two 32-bit integers to produce a
32-bit result. The Add Real (+R) and Subtract Real (--R)
instructions add or subtract two 32-bit real numbers to
produce a 32-bit real number result.
Multiply
IN1 * IN2 = OUT
FBD
IN1 * OUT = OUT
The Multiply Integer (*I) or Divide Integer (/I) instructions
multiply or divide two 16-bit integers to produce a 16-bit
result. (For division, no remainder is kept.) The Multiply
Double Integer (*D) or Divide Double Integer (/D) instructions
multiply or divide two 32-bit integers to produce a 32-bit
result. (For division, no remainder is kept.) The Multiply Real
(*R) or Divide Real (/R) instructions multiply or divide two
32-bit real numbers to produce a 32-bit real number result.
SM Bits and ENO
SM1.1 indicates overflow errors and illegal values. If SM1.1
is set, then the status of SM1.0 and SM1.2 is not valid and
the original input operands are not altered. If SM1.1 and
SM1.3 are not set, then the math operation has completed
with a valid result and SM1.0 and SM1.2 contain valid
status. If SM1.3 is set during a divide operation, then the
other math status bits are left unchanged.
Error conditions that set
ENO = 0
H SM1.1 (overflow)
H SM1.3 (divide by zero)
H 0006 (indirect address)
Table 6-39 Valid Operands for Add, Subtract, Multiply, and Divide Instructions
Inputs/Outputs
IN1, IN2
OUT
Real (or floating-point) numbers are represented in the format described in the ANSI/IEEE 754- -1985 standard
(single-precision). Refer to that standard for more information.
140
Subtract
IN1 -- IN2 = OUT
OUT -- IN1 = OUT
Divide
IN1 / IN2 = OUT
OUT / IN1 = OUT
Special Memory bits affected
H SM1.0 (zero)
H SM1.1 (overflow, illegal value generated during the operation, or illegal
input parameter found)
H SM1.2 (negative)
H SM1.3 (divide by zero)
Data Types Operands
INT IW, QW, VW, MW, SMW, SW, T, C, LW, AC, AIW, *VD, *AC, *LD, Constant
DINT ID, QD, VD, MD, SMD, SD, LD, AC, HC, *VD, *LD, *AC, Constant
REAL ID, QD, VD, MD, SMD, SD, LD, AC, *VD, *LD, *AC, Constant
INT IW, QW, VW, MW, SMW, SW, LW, T, C, AC, *VD, *AC, *LD
DINT, REAL ID, QD, VD, MD, SMD, SD, LD, AC, *VD, *LD, *AC
LAD and
STL
LAD and
STL