cvttps2pi
Convert with Truncation Packed Single to Packed Integer (MMX)
Converts packed floats to packed MMX integers (Truncate).
Pseudocode Operation
mm[0:31] ← truncate_to_int32(src[0:31]); mm[32:63] ← truncate_to_int32(src[32:63]);Example
Encoding
Operands
-
dest
64-bit MMX register -
src
128-bit XMM register or 64-bit memory
Related
More in SSE
Reference
Instruction Forms
| Opcode | Instruction | Op/En | 64/32-bit Mode | CPUID | Description |
|---|---|---|---|---|---|
| NP 0F 2C /r | CVTTPS2PI mm, xmm/m64 | RM | Valid Valid | Convert two single precision floating-point values from xmm/m64 to two signed doubleword signed integers in mm using truncation. |
Description
Converts two packed single 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 64-bit memory location. The destination operand is an MMX technology register. When the source operand is an XMM register, the two single precision floating-point values are contained in the low quadword of the register. 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. 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 CVTTPS2PI instruction is executed. In 64-bit mode, use of the REX.R prefix permits this instruction to access additional registers (XMM8-XMM15).
Operation
DEST[31:0] := Convert_Single_Precision_Floating_Point_To_Integer_Truncate(SRC[31:0]); DEST[63:32] := Convert_Single_Precision_Floating_Point_To_Integer_Truncate(SRC[63:32]);
Intel C/C++ Compiler Intrinsic Equivalent
CVTTPS2PI __m64 _mm_cvttps_pi32(__m128 a)