A.5.220 PFRCP: Packed Single-Precision FP Reciprocal Approximation
PFRCP mm1,mm2/m64 ; 0F 0F /r 96 [PENT,3DNOW]
PFRCP performs a low precision estimate of the reciprocal of the low-
order single-precision FP value in the source operand, storing the
result in both halves of the destination register. The result is
accurate to 14 bits.
For higher precision reciprocals, this instruction should be followed by
two more instructions: PFRCPIT1 (section A.5.221) and PFRCPIT2 (section
A.5.221). This will result in a 24-bit accuracy. For more details, see
the AMD 3DNow! technology manual.