VCVTTSH2USI - Convert with Truncation Low FP16 Value to an Unsigned Integer

Opcode/ Instruction

Op/ En

64/32 bit Mode Support

CPUID Feature Flag

Description

EVEX.LLIG.F3.MAP5.W0 78 /r VCVTTSH2USI r32, xmm1/m16 {sae}

A

V/V1

AVX512-FP16

Convert FP16 value in the low element of xmm1/ m16 to an unsigned integer and store the result in r32 using truncation.

EVEX.LLIG.F3.MAP5.W1 78 /r VCVTTSH2USI r64, xmm1/m16 {sae}

A

V/N.E.

AVX512-FP16

Convert FP16 value in the low element of xmm1/ m16 to an unsigned integer and store the result in r64 using truncation.

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)

ModRM:r/m (r)

N/A

N/A

Description

This instruction converts the low FP16 element in the source operand to an unsigned integer in the destination general purpose register.

When a conversion is inexact, a truncated (round toward zero) value is returned. If a converted result cannot be represented in the destination format, the floating-point invalid exception is raised, and if this exception is masked, the integer indefinite value is returned.

Operation

VCVTTSH2USI dest, src 

IF 64-mode and OperandSize == 64:
   DEST.qword := Convert_fp16_to_unsigned_integer64_truncate(SRC.fp16[0])
ELSE:
   DEST.dword := Convert_fp16_to_unsigned_integer32_truncate(SRC.fp16[0])

Intel C/C++ Compiler Intrinsic Equivalent 

VCVTTSH2USI unsigned int _mm_cvtt_roundsh_u32 (__m128h a, int sae);
VCVTTSH2USI unsigned __int64 _mm_cvtt_roundsh_u64 (__m128h a, int sae);
VCVTTSH2USI unsigned int _mm_cvttsh_u32 (__m128h a);
VCVTTSH2USI unsigned __int64 _mm_cvttsh_u64 (__m128h a);

SIMD Floating-Point Exceptions

Invalid, Precision.

Other Exceptions

EVEX-encoded instructions, see Table 2-48, "Type E3NF Class Exception Conditions."