Intel 253666-024US - Manual (Page 274)

3-228 Vol. 2A CVTSI2SS—Convert Doubleword Integer to Scalar Single-Precision Floating-Point Value
INSTRUCTION SET REFERENCE, A-M
CVTSI2SS—Convert Doubleword Integer to Scalar Single-Precision
Floating-Point Value
Description
Converts a signed doubleword integer (or signed quadword integer if operand size is
64 bits) in the source operand (second operand) to a single-precision floating-point
value in the destination operand (first operand). The source operand can be a
general-purpose register or a memory location. The destination operand is an XMM
register. The result is stored in the low doubleword of the destination operand, and
the upper three doublewords are left unchanged. When a conversion is inexact, the
value returned is rounded according to the rounding control bits in the MXCSR
register.
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 operands. See the summary chart at the beginning of this
section for encoding data and limits.
Operation
IF 64-Bit Mode And OperandSize = 64
THEN
DEST[31:0] ← Convert_Integer_To_Single_Precision_Floating_Point(SRC[63:0]);
(* DEST[127:32] unchanged *)
ELSE
DEST[31:0] ← Convert_Integer_To_Single_Precision_Floating_Point(SRC[31:0]);
(* DEST[127:32] unchanged *)
FI;
Intel C/C++ Compiler Intrinsic Equivalent
CVTSI2SS __m128 _mm_cvtsi32_ss(__m128 a, int b)
Opcode Instruction 64-Bit
Mode
Compat/
Leg Mode
Description
F3 0F 2A /r CVTSI2SS
xmm, r/m32
Valid Valid Convert one signed doubleword
integer from r/m32 to one single-
precision floating-point value in
xmm.
F3 REX.W 0F 2A /r CVTSI2SS
xmm, r/m64
Valid N.E. Convert one signed quadword
integer from r/m64 to one single-
precision floating-point value in
xmm.