Intel 253666-024US - Manual (Page 250)

3-204 Vol. 2A CVTPI2PD—Convert Packed Doubleword Integers to Packed Double-Precision Floating-
Point Values
INSTRUCTION SET REFERENCE, A-M
CVTPI2PD—Convert Packed Doubleword Integers to Packed Double-
Precision Floating-Point Values
Description
Converts two packed signed doubleword integers in the source operand (second
operand) to two packed double-precision floating-point values in the destination
operand (first operand).
The source operand can be an MMX technology register or a 64-bit memory location.
The destination operand is an XMM register. In addition, depending on the operand
configuration:
• For operands xmm, mm: the instruction causes a transition from x87 FPU to
MMX technology operation (that is, the x87 FPU top-of-stack pointer is set to 0
and the x87 FPU tag word is set to all 0s [valid]). If this instruction is executed
while an x87 FPU floating-point exception is pending, the exception is handled
before the CVTPI2PD instruction is executed.
• For operands xmm, m64: the instruction does not cause a transition to MMX
technology and does not take x87 FPU exceptions.
In 64-bit mode, use of the REX.R prefix permits this instruction to access additional
registers (XMM8-XMM15).
Operation
DEST[63:0] ← Convert_Integer_To_Double_Precision_Floating_Point(SRC[31:0]);
DEST[127:64] ← Convert_Integer_To_Double_Precision_Floating_Point(SRC[63:32]);
Intel C/C++ Compiler Intrinsic Equivalent
CVTPI2PD __m128d _mm_cvtpi32_pd(__m64 a)
SIMD Floating-Point Exceptions
None.
Opcode Instruction 64-Bit
Mode
Compat/
Leg Mode
Description
66 0F 2A /r CVTPI2PD
xmm,
mm/m64*
Valid Valid Convert two packed signed
doubleword integers from
mm/mem64 to two packed double-
precision floating-point values in
xmm.
NOTES:
* Operation is different for different operand sets; see the Description section.