◄Up► ◄Contents► ◄Index► ◄Back► ──────────────────────────────────────────────────────────────────────────── 15 8 7 0 ┌──┬──┬──┬──┬──┬──┬──┬──┐┌──┬──┬──┬──┬──┬──┬──┬──┐ │ │ │ │ │ │ ││ │ │ │ │ │ │ │ │ │B │C3│ ST │C2│C1│C0││ES│SF│PE│UE│OE│ZE│DE│IE│◄── Status word │ │ │ │ │ │ ││IR│ │ │ │ │ │ │ │ └──┴──┴──┴──┴──┴──┴──┴──┘└──┴──┴──┴──┴──┴──┴──┴──┘ B──Busy 1 if exception control unit active C3, C2, C1, and C0──Condition codes The high byte can be loaded into processor flags with SAHF instruction. Coprocessor flags line up with processor flags as shown below: 15 8 ┌──┬──┬──┬──┬──┬──┬──┬──┐ │ │C3│ │ │ │C2│C1│C0│◄── Coprocessor └──┴──┴──┴──┴──┴──┴──┴──┘ 7 0 ┌──┬──┬──┬──┬──┬──┬──┬──┐ │SF│ZF│ │AF│ │PF│ │CF│◄── Processor └──┴──┴──┴──┴──┴──┴──┴──┘ ST──Stack Top Pointer Number (0 to 7) of register at current top of stack. ES/IR──Interrupt Request or Error Summary On 8087 1 if interrupt request On 80287, 80387, or 80486, 1 if any exception SF──Stack Flag On 80387 or 80486, 1 if stack overflow or underflow On 8087 and 80287, undefined Exception Flags PE = 1 if precision exception UE = 1 if underflow exception OE = 1 if overflow exception ZE = 1 if zero divide exception IE = 1 if invalid operation exception See also: Coprocessor Control Word, Coprocessor Environment -♦-