CVTTSS2SI (Convert with Truncation Scalar Single-Precision FP Value to Dword Integer)
|Opcode/Instruction||Op/ En||64/32-bit Mode||CPUID Feature Flag||Description|
|F3 0F 2C /r CVTTSS2SI r32, xmm/m32||RM||V/V||SSE||Convert one single-precision floating-point value from xmm/m32 to one signed doubleword integer in r32 using truncation.|
|F3 REX.W 0F 2C /r CVTTSS2SI r64, xmm/m32||RM||V/N.E.||SSE||Convert one single-precision floating-point value from xmm/m32 to one signed quadword integer in r64 using truncation.|
|VEX.LIG.F3.0F.W0 2C /r VCVTTSS2SI r32, xmm1/m32||RM||V/V||AVX||Convert one single-precision floating-point value from xmm1/m32 to one signed doubleword integer in r32 using truncation.|
|VEX.LIG.F3.0F.W1 2C /r VCVTTSS2SI r64, xmm1/m32||RM||V/N.E.1||AVX||Convert one single-precision floating-point value from xmm1/m32 to one signed quadword integer in r64 using truncation.|
1. Encoding the VEX prefix with VEX.W=1 in non-64-bit mode is ignored.
Instruction Operand Encoding
|Op/En||Operand 1||Operand 2||Operand 3||Operand 4|
|RM||ModRM:reg (w)||ModRM:r/m (r)||NA||NA|
Converts a single-precision floating-point value in the source operand (second operand) to a signed doubleword integer (or signed quadword integer if operand size is 64 bits) in the destination operand (first operand). The source operand can be an XMM register or a 32-bit memory location. The destination operand is a general-purpose register. When the source operand is an XMM register, the single-precision floating-point value is contained in the low doubleword 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. If this exception is masked, the indefinite integer value (80000000H) is returned.
Legacy SSE instructions: In 64-bit mode, the instruction can access additional registers (XMM8-XMM15, R8-R15) when used with a REX.R prefix. Use of the REX.W prefix promotes the instruction to 64-bit operation. See the summary chart at the beginning of this section for encoding data and limits.
Note: In VEX-encoded versions, VEX.vvvv is reserved and must be 1111b, otherwise instructions will #UD.
IF 64-Bit Mode and OperandSize = 64 THEN DEST[63:0] ← Convert_Single_Precision_Floating_Point_To_ Integer_Truncate(SRC[31:0]); ELSE DEST[31:0] ← Convert_Single_Precision_Floating_Point_To_ Integer_Truncate(SRC[31:0]); FI;
Intel C/C++ Compiler Intrinsic Equivalent
int _mm_cvttss_si32(__m128d a)
__int64 _mm_cvttss_si64(__m128d a)
SIMD Floating-Point Exceptions
See Exceptions Type 3; additionally
|#UD||If VEX.vvvv ≠ 1111B.|