RCPSS—Compute Reciprocal of Scalar Single-Precision Floating-Point ValuesInstruction Operand EncodingDescriptionComputes of an approximate reciprocal of the low single-precision floating-point value in the source operand (second operand) and stores the single-precision floating-point result in the destination operand. The source operand can be an XMM register or a 32-bit memory location. The destination operand is an XMM register. The three high-order doublewords of the destination operand remain unchanged. See Figure 10-6 in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1, for an illustration of a scalar single-precision floating-point operation.The relative error for this approximation is:|Relative Error| ≤ 1.5 ∗ 2−12The RCPSS instruction is not affected by the rounding control bits in the MXCSR register. When a source value is a 0.0, an ∞ of the sign of the source value is returned. A denormal source value is treated as a 0.0 (of the same sign). Tiny results (see Section 4.9.1.5, “Numeric Underflow Exception (#U)” in Intel® 64 and IA-32 Architectures Soft-ware Developer’s Manual, Volume 1) are always flushed to 0.0, with the sign of the operand. (Input values greater than or equal to |1.11111111110100000000000B∗2125| are guaranteed to not produce tiny results; input values less than or equal to |1.00000000000110000000001B*2126| are guaranteed to produce tiny results, which are in turn flushed to 0.0; and input values in between this range may or may not produce tiny results, depending on the implementation.) When a source value is an SNaN or QNaN, the SNaN is converted to a QNaN or the source QNaN is returned.In 64-bit mode, using a REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15).128-bit Legacy SSE version: The first source operand and the destination operand are the same. Bits (MAXVL-1:32) of the corresponding YMM destination register remain unchanged.VEX.128 encoded version: Bits (MAXVL-1:128) of the destination YMM register are zeroed.OperationRCPSS (128-bit Legacy SSE version)DEST[31:0] := APPROXIMATE(1/SRC[31:0])DEST[MAXVL-1:32] (Unmodified)Opcode*/InstructionOp/ En64/32 bit Mode SupportCPUID Feature FlagDescriptionF3 0F 53 /rRCPSS xmm1, xmm2/m32RMV/VSSEComputes the approximate reciprocal of the scalar single-precision floating-point value in xmm2/m32 and stores the result in xmm1.VEX.LIG.F3.0F.WIG 53 /rVRCPSS xmm1, xmm2, xmm3/m32RVMV/VAVXComputes the approximate reciprocal of the scalar single-precision floating-point value in xmm3/m32 and stores the result in xmm1. Also, upper single precision floating-point values (bits[127:32]) from xmm2 are copied to xmm1[127:32].Op/EnOperand 1Operand 2Operand 3Operand 4RMModRM:reg (w)ModRM:r/m (r)NANARVMModRM:reg (w)VEX.vvvv (r)ModRM:r/m (r)NA
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