# RSQRTPS
# Compute Reciprocals of Square Roots of Packed Single-Precision Floating-Point Values
| Opcode | Mnemonic | Description |
|---|---|---|
| 0F 52 /r | RSQRTPS xmm1, xmm2/m128 | Compute the approximate reciprocals of the square roots of the packed single-precision floating-point values in xmm2/m128 and store the results in xmm1. |
# Description
Performs an SIMD computation of the approximate reciprocals of the square roots of the four packed single-precision floating-point values in the source operand (second operand) and stores the packed single-precision floating-point results in the destination operand. The source operand can be an XMM register or a 128-bit memory location. The destination operand is an XMM register. See Figure 10-5 in the IA-32 Intel Architecture Software Developer's Manual, Volume 1 for an illustration of an SIMD single-precision floating-point operation.
The relative error for this approximation is:
|Relative Error| <= 1.5 * 2-12 The RSQRTPS instruction is not affected by the rounding control bits in the MXCSR register.
When a source value is a 0.0, an infinite of the sign of the source value is returned. A denormal source value is treated as a 0.0 (of the same sign). When a source value is a negative value (other than -0.0), a floating-point indefinite is returned. When a source value is an SNaN or QNaN, the SNaN is converted to a QNaN or the source QNaN is returned.
# Operation
Destination[0..31] = Approximate(1.0 / SquareRoot(Source[0..31]));
Destination[32..63] = Approximate(1.0 / SquareRoot(Source[32..63]));
Destination[64..95] = Approximate(1.0 / SquareRoot(Source[64..95]));
Destination[96..127] = Approximate(1.0 / SquareRoot(Source[96..127]));
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| Instruction | Latency | Throughput | Execution Unit |
|---|---|---|---|
| CPUID | 0F3n/0F2n/069n | 0F3n/0F2n/069n | 0F2n |
| RSQRTPS xmm, xmm | 6/6/2 | 4/4/2 | MMX_MISC |