FSTSW
Usage: FSTSW dest Modifies flags: See below
Stores the current value of the x87 FPU status word in the 'dest' location. The 'dest' can be either a two-byte memory location or the AX register. The FSTSW instruction checks for and handles pending unmasked floating - point exceptions before storing the status word; the FNSTSW instruction does not.
Store Floating-Point Status Word
FSTSW mem16 ; 9B DD /7 [8086,FPU]
FSTSW AX ; 9B DF E0 [286,FPU]
FNSTSW mem16 ; DD /7 [8086,FPU]
FNSTSW AX ; DF E0 [286,FPU]
FSTSW stores the FPU status word into AX or into a 2-byte memory area.
FNSTSW does the same thing as FSTSW, without first waiting for pending floating-point exceptions to clear.
FPU Flags Affected The C0, C1, C2, and C3 are undefined.
EXAMPLE:
fstsw Label
FSTSW
Usage: FSTSW dest Modifies flags: See below
Stores the current value of the x87 FPU status word in the 'dest' location. The 'dest' can be either a two-byte memory location or the AX register. The FSTSW instruction checks for and handles pending unmasked floating - point exceptions before storing the status word; the FNSTSW instruction does not.
Store Floating-Point Status Word
FSTSW mem16 ; 9B DD /7 [8086,FPU]
FSTSW AX ; 9B DF E0 [286,FPU]
FNSTSW mem16 ; DD /7 [8086,FPU]
FNSTSW AX ; DF E0 [286,FPU]
FSTSW stores the FPU status word into AX or into a 2-byte memory area.
FNSTSW does the same thing as FSTSW, without first waiting for pending floating-point exceptions to clear.
FPU Flags Affected The C0, C1, C2, and C3 are undefined.
EXAMPLE:
fstsw Label