| Opcode/Instruction | Op/En | 64-Bit Mode | Compat/Leg Mode | Description |
|---|---|---|---|---|
| NP 0F 2A /r CVTPI2PS xmm, mm/m64 | RM | Valid | Valid | Convert two signed doubleword integers from mm/m64 to two single-precision floating-point values in xmm. |
| Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
| RM | ModRM:reg (w) | ModRM:r/m (r) | NA | NA |
Converts two packed signed doubleword integers in the source operand (second operand) to two packed single-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. The results are stored in the low quadword of the destination operand, and the high quadword remains unchanged. When a conversion is inexact, the value returned is rounded according to the rounding control bits in the MXCSR register.
This 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 CVTPI2PS instruction is executed.
In 64-bit mode, use of the REX.R prefix permits this instruction to access additional registers (XMM8-XMM15).
DEST[31:0] ← Convert_Integer_To_Single_Precision_Floating_Point(SRC[31:0]); DEST[63:32] ← Convert_Integer_To_Single_Precision_Floating_Point(SRC[63:32]); (* High quadword of destination unchanged *)
CVTPI2PS: __m128 _mm_cvtpi32_ps(__m128 a, __m64 b)
Precision
See Table 22-5, “Exception Conditions for Legacy SIMD/MMX Instructions with XMM and FP Exception,” in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3B.