4.10.16 VAX Floating Divide

Format:

DIVxFa.rx,Fb.rx,Fc.wx!Floating-point Operate format

Operation:

Fc Fav / Fbv

Exceptions:

Invalid Operation

Division by Zero

Overflow

Underflow

Instruction mnemonics:

DIVF

Divide F_floating

DIVG

Divide G_floating

Qualifiers:

Rounding:

Chopped (/C)

Trapping:

Exception Completion (/S)

 

Underflow Enable (/U)

Description:

The dividend operand in register Fa is divided by the divisor operand in register Fb and the quotient is written to register Fc.

The quotient is rounded or chopped to the specified precision and then the corresponding range is checked for overflow/underflow. The single-precision operation on canonical single-preci- sion values produces a canonical single-precision result.

An invalid operation trap is signaled if either operand has exp=0 and is not a true zero (that is, VAX reserved operands and dirty zeros trap). The contents of Fc are UNPREDICTABLE if this occurs.

A division by zero trap is signaled if Fbv is zero. The contents of Fc are UNPREDICTABLE if this occurs.

See Section 4.7.7 for details of the stored result on overflow or underflow.

Instruction Descriptions 4–121

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Compaq ECQD2KCTE manual VAX Floating Divide, Divf