Status Bit Instructions

Overview of Status Bit Instructions

The status bit instructions are bit logic instructions that work with the bits of the status word (see CPU Registers). Each of these instructions reacts to one of the following conditions that is indicated by one or more bits of the status word:

·       The binary result bit (BR) is set (has a signal state of 1).

·       The result of a math function is relative to 0 in one of the following ways: == 0,

<> 0, > 0, < 0, >= 0, <= 0.

·       The result of a math function is unordered (UO).

·       A math function produced an overflow (OV) or a or a stored overflow (OS). When a status bit instruction is connected in series, it combines the result of its

signal state check with the previous result of logic operation according to the And truth table. When a status bit instruction is connected in parallel, it combines its result with the previous RLO according to the Or truth table.

Status Word

The status word is a Register in the memory of your CPU that contains bits that

you can reference in the address of bit and word logic instructions. Structure of the status word:

215...                        ..29       28             27            26             25             24              23             22         21             20

BR

CC1

CC0

OV

OS

OR

STA

RLO

/FC

You can evaluate the bits in the status word

·       by Integer Math Functions

·       by Floating-Point Functions