image/svg+xml FSQRT—Square Root Description 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. This instruction’s operation is the same in non-64-bit modes and 64-bit mode. Operation ST(0) := SquareRoot(ST(0)); FPU Flags Affected C1Set to 0 if stack underflow occurred. Set if result was rounded up; cleared otherwise. C0, C2, C3 Undefined. Floating-Point Exceptions #ISStack underflow occurred. #IASource operand is an SNaN value or unsupported format. Source operand is a negative value (except for − 0). #DSource operand is a denormal value. #PValue cannot be represented exactly in destination format. Protected Mode Exceptions #NMCR0.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. Real-Address Mode Exceptions Same exceptions as in protected mode. OpcodeInstruction64-Bit Mode Compat/ Leg Mode Description D9 FAFSQRTValidValidComputes square root of ST(0) and stores the result in ST(0). Table 3-37. FSQRT Results SRC (ST(0))DEST (ST(0)) − ∞ * − F * − 0 − 0 + 0 + 0 + F + F + ∞ + ∞ NaN NaN NOTES: FMeans finite floating-point value. *Indicates floating-point invalid-arithmetic-operand (#IA) exception. image/svg+xml Virtual-8086 Mode Exceptions Same exceptions as in protected mode. Compatibility Mode Exceptions Same exceptions as in protected mode. 64-Bit Mode Exceptions Same exceptions as in protected mode. This UNOFFICIAL reference was generated from the official Intel® 64 and IA-32 Architectures Software Developer’s Manual by a dumb script. There is no guarantee that some parts aren't mangled or broken and is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE .