4.10.5 VAX Floating Add
Format:
ADDxFa.rx,Fb.rx,Fc.wx!Floating-point Operate format
Operation:
Fc ← Fav + Fbv
Exceptions:
Invalid Operation
Overflow
Underflow
Instruction mnemonics:
ADDF | Add F_floating |
ADDG | Add G_floating |
Qualifiers:
Rounding: | Chopped (/C) |
Trapping: | Exception Completion (/S) |
| Underflow Enable (/U) |
Description:
Register Fa is added to register Fb, and the sum is written to register Fc.
The sum is rounded or chopped to the specified precision, and then the corresponding range is checked for overflow/underflow. The
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. See Section 4.7.7 for details of the stored result on overflow or underflow.