VRANGESD

Range Restriction Calculation From a pair of Scalar Float64 Values

참고 사항

Instruction Operand Encoding

Description

This instruction calculates a range operation output from two input double-precision FP values in the low qword element of the first source operand (the second operand) and second source operand (the third operand). The range output is written to the low qword element of the destination operand (the first operand) under the writemask k1.

Bits7:4 of imm8 byte must be zero. The range operation output is performed in two parts, each configured by a two-bit control field within imm8[3:0]:

• Imm8[1:0] specifies the initial comparison operation to be one of max, min, max absolute value or min absolute value of the input value pair. Each comparison of two input values produces an intermediate result that combines with the sign selection control (Imm8[3:2]) to determine the final range operation output.

• Imm8[3:2] specifies the sign of the range operation output to be one of the following: from the first input value, from the comparison result, set or clear.

The encodings of Imm8[1:0] and Imm8[3:2] are shown in Figure 5-27.

Bits 128:63 of the destination operand are copied from the respective element of the first source operand.

When one or more of the input value is a NAN, the comparison operation may signal invalid exception (IE). Details with one of more input value is NAN is listed in Table 5-12. If the comparison raises an IE, the sign select control (Imm8[3:2] has no effect to the range operation output, this is indicated also in Table 5-12.

When both input values are zeros of opposite signs, the comparison operation of MIN/MAX in the range compare operation is slightly different from the conceptually similar FP MIN/MAX operation that are found in the instructions VMAXPD/VMINPD. The details of MIN/MAX/MINABS/MAXABS operation for VRANGEPD/PS/SD/SS for magni-tude-0, opposite-signed input cases are listed in Table 5-13.

Additionally, non-zero, equal-magnitude with opposite-sign input values perform MINABS or MAXABS compar-ison operation with result listed in Table 5-14.

Operation

VRANGESD

IF k1[0] OR *no writemask*
          THEN DEST[63:0] <-  RangeDP (SRC1[63:0], SRC2[63:0], CmpOpCtl[1:0], SignSelCtl[1:0]);
    ELSE 
          IF *merging-masking* ; merging-masking
                THEN *DEST[63:0] remains unchanged*
                ELSE  ; zeroing-masking
                      DEST[63:0] = 0
          FI;
FI;
DEST[127:64] <-  SRC1[127:64]
DEST[MAX_VL-1:128] <-  0
The following example describes a common usage of this instruction for checking that the input operand isbounded between $$\pm$$1023.
VRANGESD xmm_dst, xmm_src, xmm_1023, 02h;
Where:
xmm_dst is the destination operand.
xmm_src is the input operand to compare against $$\pm$$1023.
xmm_1023 is the reference operand, contains the value of 1023.
IMM=02(imm8[1:0]='10) selects the Min Absolute value operation with selection of src1.sign.
In case |xmm_src| < 1023, then its value will be written into xmm_dst. Otherwise, the value stored in xmm_dstwill get the value of 1023 (received on xmm_1023).
However, the sign control (imm8[3:2]='00) instructs to select the sign of SRC1 received from xmm_src. So, evenin the case of |xmm_src| *   1023, the selected sign of SRC1 is kept. 
Thus, if xmm_src < -1023, the result of VRANGEPD will be the minimal value of -1023while if xmm_src > +1023,the result of VRANGE will be the maximal value of +1023.

Intel C/C++ Compiler Intrinsic Equivalent

VRANGESD __m128d _mm_range_sd(__m128d a, __m128d b, int imm);
VRANGESD __m128d _mm_range_round_sd(__m128d a, __m128d b, int imm, int sae);
VRANGESD __m128d _mm_mask_range_sd(__m128d s, __mmask8 k, __m128d a, __m128d b,
                                   int imm);
VRANGESD __m128d _mm_mask_range_round_sd(__m128d s, __mmask8 k, __m128d a,
                                         __m128d b, int imm, int sae);
VRANGESD __m128d _mm_maskz_range_sd(__mmask8 k, __m128d a, __m128d b, int imm);
VRANGESD __m128d _mm_maskz_range_round_sd(__mmask8 k, __m128d a, __m128d b,
                                          int imm, int sae);

SIMD Floating-Point Exceptions

Invalid, Denormal

Other Exceptions

See Exceptions Type E3.

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