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Floating-point convert from single-precision to BFloat16 format (scalar) converts the single-precision floating-point value in the 32-bit SIMD&FP source register to BFloat16 format and writes the result in the 16-bit SIMD&FP destination register.

Unlike the BFloat16 multiplication instructions, this instruction honors all the control bits in the FPCR that apply to single-precision arithmetic, including the rounding mode. This instruction can generate a floating-point exception that causes a cumulative exception bit in the FPSR to be set, or a synchronous exception to be taken, depending on the enable bits in the FPCR. ID_AA64ISAR1_EL1.BF16 indicates whether this instruction is supported.

Single-precision to BFloat16


BFCVT <Hd>, <Sn>

if !HaveBF16Ext() then UNDEFINED;
integer n = UInt(Rn);
integer d = UInt(Rd);

Assembler Symbols


Is the 16-bit name of the SIMD&FP destination register, encoded in the "Rd" field.


Is the 32-bit name of the SIMD&FP source register, encoded in the "Rn" field.



bits(32) operand = V[n];
FPCRType fpcr = FPCR[];
boolean merge = IsMerging(fpcr);
bits(128) result = if merge then V[d] else Zeros();

Elem[result, 0, 16] = FPConvertBF(operand, fpcr);

V[d] = result;