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VCVTSI2SH

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Henk-Jan Lebbink edited this page Jun 4, 2026 · 1 revision

VCVTSI2SH — Convert a Signed Doubleword/Quadword Integer to an FP16 Value

Opcode/ Instruction Op/ En 64/32 Bit Mode Support1 CPUID Feature Flag Description
EVEX.LLIG.F3.MAP5.W0 2A /r VCVTSI2SH xmm1, xmm2, r32/m32 {er} AV/V 1 AVX512_FP16 OR AVX10.1 Convert the signed doubleword integer in r32/m32 to an FP16 value and store the result in xmm1. Bits 127:16 of xmm2 are copied to xmm1[127:16].
EVEX.LLIG.F3.MAP5.W1 2A /r VCVTSI2SH xmm1, xmm2, r64/m64 {er} A V/N.E. AVX512_FP16 OR AVX10.1 Convert the signed quadword integer in r64/m64 to an FP16 value and store the result in xmm1. Bits 127:16 of xmm2 are copied to xmm1[127:16].

NOTES:

  1. Outside of 64b mode, the EVEX.W field is ignored. The instruction behaves as if W=0 was used.

Instruction Operand Encoding

Op/En Tuple Operand 1 Operand 2 Operand 3 Operand 4
A Scalar ModRM:reg (w) VEX.vvvv (r) ModRM:r/m (r) N/A

Description

This instruction converts a signed doubleword integer (or signed quadword integer if operand size is 64 bits) in the second source operand to an FP16 value in the destination operand. The result is stored in the low word of the destination operand. When conversion is inexact, the value returned is rounded according to the rounding control bits in the MXCSR register or embedded rounding controls.

The second source operand can be a general-purpose register or a 32/64-bit memory location. The first source and destination operands are XMM registers. Bits 127:16 of the XMM register destination are copied from corresponding bits in the first source operand. Bits MAXVL-1:128 of the destination register are zeroed.

If the result of the convert operation is overflow and MXCSR.OM=0 then a SIMD exception will be raised with OE=1, PE=1.

Operation

VCVTSI2SH dest, src1, src2

IF *SRC2 is a register* and (EVEX.b = 1):
    SET_RM(EVEX.RC)
ELSE:
    SET_RM(MXCSR.RC)
IF 64-mode and OperandSize == 64:
    DEST.fp16[0] ← Convert_integer64_to_fp16(SRC2.qword)
ELSE:
    DEST.fp16[0] ← Convert_integer32_to_fp16(SRC2.dword)
DEST[127:16] ← SRC1[127:16]

Intel C/C++ Compiler Intrinsic Equivalent

VCVTSI2SH __m128h _mm_cvt_roundi32_sh (__m128h a, int b, int rounding);
VCVTSI2SH __m128h _mm_cvt_roundi64_sh (__m128h a, __int64 b, int rounding);
VCVTSI2SH __m128h _mm_cvti32_sh (__m128h a, int b);
VCVTSI2SH __m128h _mm_cvti64_sh (__m128h a, __int64 b);

SIMD Floating-Point Exceptions

Overflow, Precision.

Other Exceptions

Source: Intel® 64 and IA-32 Architectures Software Developer's Manual, Combined Volumes (Order Number 325462-091US, March 2026)
Generated: 7-6-2026

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