Square Root
Hex | Mnemonic | Encoding | Long Mode | Legacy Mode | Description |
---|---|---|---|---|---|
D9 FA | FSQRT | None | 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 |
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 are undefined.
Exception | Description |
---|---|
#P | Value cannot be represented exactly in destination format. |
#D | Source operand is a denormal value. |
#IA | Source operand is an SNaN value or unsupported format. Source operand is a negative value (except for -0). |
#IS | Stack underflow occurred. |
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Same exceptions as in protected mode.
Exception | Description |
---|---|
#UD | If the LOCK prefix is used. |
#MF | If there is a pending x87 FPU exception. |
#NM | CR0.EM[bit 2] or CR0.TS[bit 3] = 1. |