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3-240 Vol. 2A CVTTPD2DQ—Convert with Truncation Packed Double-Precision Floating-Point Values
to Packed Doubleword Integers
INSTRUCTION SET REFERENCE, A-M
CVTTPD2DQ—Convert with Truncation Packed Double-Precision
Floating-Point Values to Packed Doubleword Integers
Description
Converts two packed double-precision floating-point values in the source operand
(second operand) to two packed signed doubleword integers in the destination
operand (first operand). The source operand can be an XMM register or a 128-bit
memory location. The destination operand is an XMM register. The result is stored in
the low quadword of the destination operand and the high quadword is cleared to all
0s.
When a conversion is inexact, a truncated (round toward zero) result is returned. If a
converted result is larger than the maximum signed doubleword integer, the floating-
point invalid exception is raised, and if this exception is masked, the indefinite
integer value (80000000H) is returned.
In 64-bit mode, use of the REX.R prefix permits this instruction to access additional
registers (XMM8-XMM15).
Operation
DEST[31:0] ← Convert_Double_Precision_Floating_Point_To_Integer_Truncate(SRC[63:0]);
DEST[63:32] ← Convert_Double_Precision_Floating_Point_To_Integer_
Truncate(SRC[127-64]);
DEST[127:64] ← 0000000000000000H;
Intel C/C++ Compiler Intrinsic Equivalent
CVTTPD2DQ __m128i _mm_cvttpd_epi32(__m128d a)
SIMD Floating-Point Exceptions
Invalid, Precision.
Protected Mode Exceptions
#GP(0) For an illegal memory operand effective address in the CS, DS,
ES, FS or GS segments.
Opcode Instruction 64-Bit
Mode
Compat/
Leg Mode
Description
66 0F E6 CVTTPD2DQ xmm1,
xmm2/m128
Valid Valid Convert two packed double-
precision floating-point values
from xmm2/m128 to two packed
signed doubleword integers in
xmm1 using truncation.