66 0F C2 /r ib CMPPD xmm1, xmm2/m128, imm8 RMI V/V SSE2 Compare packed double-precision floating-point values in xmm2/m128 and xmm1 using imm8 as comparison predicate.
VEX.NDS.128.66.0F.WIG C2 /r ib VCMPPD xmm1, xmm2, xmm3/m128, imm8 RVMI V/V AVX Compare packed double-precision floating-point values in xmm3/m128 and xmm2 using bits 4:0 of imm8 as a comparison predicate.
VEX.NDS.256.66.0F.WIG C2 /r ib VCMPPD ymm1, ymm2, ymm3/m256, imm8 RVMI V/V AVX Compare packed double-precision floating-point values in ymm3/m256 and ymm2 using bits 4:0 of imm8 as a comparison predicate.
Performs a SIMD compare of the packed double-precision floating-point values in the source operand (second operand) and the destination operand (first operand) and returns the results of the comparison to the destination operand. The comparison predicate operand (third operand) specifies the type of comparison performed on each of the pairs of packed values. The result of each comparison is a quadword mask of all 1s (comparison true) or all 0s (comparison false). The sign of zero is ignored for comparisons, so that –0.0 is equal to +0.0.
128-bit Legacy SSE version: The first source and destination operand (first operand) is an XMM register. The second source operand (second operand) can be an XMM register or 128-bit memory location. The comparison predicate operand is an 8-bit immediate, bits 2:0 of the immediate define the type of comparison to be performed (see Table 3-7). Bits 7:3 of the immediate is reserved. Bits (VLMAX-1:128) of the corresponding YMM destination register remain unchanged. Two comparisons are performed with results written to bits 127:0 of the destination operand.
Note that the processors with “CPUID.1H:ECX.AVX =0” do not implement the greater-than, greater-than-or-equal, not-greater-than, and not-greater-than-or-equal relations. These comparisons can be made either by using the inverse relationship (that is, use the “not-less-than-or-equal” to make a “greater-than” comparison) or by using software emulation. When using software emulation, the program must swap the operands (copying registers when necessary to protect the data that will now be in the destination), and then perform the compare using a different predicate. The predicate to be used for these emulations is listed in Table 3-7 under the heading Emula-tion.
Compilers and assemblers may implement the following two-operand pseudo-ops in addition to the three-operand CMPPD instruction, for processors with “CPUID.1H:ECX.AVX =0”. See Table 3-8. Compiler should treat reserved Imm8 values as illegal syntax.
VEX.128 encoded version: The first source operand (second operand) is an XMM register. The second source operand (third operand) can be an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the destina-tion YMM register are zeroed. Two comparisons are performed with results written to bits 127:0 of the destination operand.
VEX.256 encoded version: The first source operand (second operand) is a YMM register. The second source operand (third operand) can be a YMM register or a 256-bit memory location. The destination operand (first operand) is a YMM register. Four comparisons are performed with results written to the destination operand.
1. If either operand A or B is a NAN.
Processors with “CPUID.1H:ECX.AVX =1” implement the full complement of 32 predicates shown in Table 3-9, soft-ware emulation is no longer needed. Compilers and assemblers may implement the following three-operand pseudo-ops in addition to the four-operand VCMPPD instruction. See Table 3-10, where the notations of reg1 reg2, and reg3 represent either XMM registers or YMM registers. Compiler should treat reserved Imm8 values as illegal syntax. Alternately, intrinsics can map the pseudo-ops to pre-defined constants to support a simpler intrinsic inter-face.