Mathematical Instructions

The arithmetic instructions perform the various PL/B mathematical functions. Except for the CALC instruction, they typically use the same general format.

ADD	Add two numbers with optional giving clause.
ARCCOS	Calculate the arccosine of a value.
ARCSIN	Calculate the arcsine of a value.
ARCTAN	Calculate the arctangent of a value.
ARCTAN2	Calculate the arctangent of a value returns a value in the range –pi to pi radians.
CALC	Perform algebraic type calculation.
CHECK10	Perform a check digit calculation.
CHECK11	Perform a check digit calculation.
COMPARE	Compare two numbers.
COS	Calculate the cosine of a value.
COSH	Calculate the hyperbolic cosine of a value.
DECR	Decrement a variable by one.
DIVIDE	Divide two numbers with optional giving clause.
EXP	Calculate the natural exponent of a value.
INCR	Increment a variable by one.
LOG	Calculate the natural log of a value.
LOG10	Calculate the base 10 log of a value.
MODULO	Determine the remainder of a division operation.
MULTIPLY	Multiply two numbers with optional giving clause.
NFORMAT	Format a numeric string.
POWER	Raise a value to a power.
ROTATELEFT	Left circular shift an integer.
ROTATERIGHT	Right circular shift an integer.
SHIFTLEFT	Left logical shift an integer.
SHIFTLEFTA	Left algebraic shift an integer.
SHIFTRIGHT	Right logical shift an integer.
SHIFTRIGHTA	Right algebraic shift an integer.
SIN	Calculate the sin of a value.
SINH	Calculate the hyperbolic sin of a value.
SQRT	Calculate the square root of a value.
SUBTRACT	Subtract two numbers with optional giving clause.
TAN	Calculate the tangent of a value.
TANH	Calculate the hyperbolic tangent of a value.

The arithmetic instructions use the Condition Flags: ZERO, LESS, and OVER. These flags are set or cleared depending on the results of the operation. They usually indicate the following:

Flag	Indication
ZERO	The result of the instruction was zero.
LESS	The result of the instruction was less than zero.
OVER	Significant digits were lost in the result

When the OVER Condition Flag is set, the LESS and ZERO condition indicators are unpredictable.