frsqrtes

Floating Reciprocal Square Root Estimate Single

frsqrtes FRT, FRB

Estimates 1/sqrt(x) (Single Precision).

Details

The frsqrtes instruction estimates the reciprocal of the square root of a floating-point operand in register FRB and places the result into register FRT. The estimate is accurate to within one part in 32 of the true value. Special values like -∞, +0, +∞, SNaN, and QNaN are handled according to specific rules, potentially raising exceptions.

Pseudocode Operation

FRT ← Estimate(1 / √FRB)
if (Rc == 1) CR1 ← FPRF

Programming Note

The frsqrtes instruction provides a fast estimate of the reciprocal square root, suitable for performance-critical applications where precision is less critical than speed. Be aware that it may raise exceptions for special values like NaN or infinity, and results are only accurate to within one part in 32 of the true value.

Example

frsqrtes f1, f3

Encoding

Binary Layout
59
0
FRT
6
0
11
0
16
FRB
21
26
26
/
31
 
Format A-form
Opcode 0xEC000034
Extension Floating-Point
Registers Altered FPSCR

Operands

  • FRT
    Target
  • FRB
    Source