Opcode | Instruction | 64-Bit Mode | Compat/Leg Mode | Description |
---|---|---|---|---|
D9 FA | FSQRT | Valid | Valid | Computes square root of ST(0) and stores the result in ST(0). |
Computes the square root of the source value in the ST(0) register and stores the result in ST(0).
The following table shows the results obtained when taking the square root of various classes of numbers, assuming that neither overflow nor underflow occurs.
SRC (ST(0))
DEST (ST(0))
− ∞ | * |
− F | * |
− 0 | − 0 |
+ 0 | + 0 |
+ F | + F |
+ ∞ | + ∞ |
NaN | NaN |
NOTES:
F Means finite floating-point value.
*
Indicates floating-point invalid-arithmetic-operand (#IA) exception.
This instruction’s operation is the same in non-64-bit modes and 64-bit mode.
ST(0) := SquareRoot(ST(0));
C1 |
Set to 0 if stack underflow occurred. Set if result was rounded up; cleared otherwise. |
C0, C2, C3 | Undefined. |
#IS | Stack underflow occurred. |
#IA |
Source operand is an SNaN value or unsupported format. Source operand is a negative value (except for −0). |
#D
Source operand is a denormal value.
#P
Value cannot be represented exactly in destination format.
#NM | CR0.EM[bit 2] or CR0.TS[bit 3] = 1. |
#MF | If there is a pending x87 FPU exception. |
#UD | If the LOCK prefix is used. |
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Same exceptions as in protected mode.