fcvt.wu.s

Floating-Point Convert Single-Precision to Unsigned Word

This instruction is defined by:

Encoding

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Synopsis

Converts a floating-point number in floating-point register fs1 to an unsigned 32-bit integer in integer register xd. For XLEN >32, fcvt.wu.s sign-extends the 32-bit result to the destination register width.

If the rounded result is not representable as a 32-bit unsigned integer, it is clipped to the nearest value and the invalid flag is set.

The range of valid inputs and behavior for invalid inputs are:

Value

Minimum valid input (after rounding)

0

Maximum valid input (after rounding)

2^32 - 1

Output for out-of-range negative input

0

Output for -∞

0

Output for out-of-range positive input

2^32 - 1

Output for +∞ for NaN

2^32 - 1

All floating-point to integer and integer to floating-point conversion instructions round according to the rm field.

A floating-point register can be initialized to floating-point positive zero using fcvt.s.w xd, x0, which will never set any exception flags.

All floating-point conversion instructions set the Inexact exception flag if the rounded result differs from the operand value and the Invalid exception flag is not set.

Access

M HS U VS VU

Always

Always

Always

Always

Always

Decode Variables

Bits<5> fs1 = $encoding[19:15];
Bits<3> rm = $encoding[14:12];
Bits<5> xd = $encoding[11:7];

Execution

  • Pruned, XLEN == 64

  • Original

check_f_ok($encoding);
RoundingMode rounding_mode = rm_to_mode(rm, $encoding);
X[xd] = $signed(f32_to_ui32(F[fs1], rounding_mode));
check_f_ok($encoding);
RoundingMode rounding_mode = rm_to_mode(rm, $encoding);
X[xd] = $signed(f32_to_ui32(F[fs1], rounding_mode));

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction