fcvt.w.s
Floating-Point Convert Single-Precision to Word
This instruction is defined by:
Synopsis
The fcvt.w.s instruction converts a floating-point number in floating-point register fs1 to a
signed 32-bit integer in integer register xd. For XLEN >32, fcvt.w.s sign-extends the 32-bit
result to the destination register width.
If the rounded result is not representable as a 32-bit signed 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) |
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Maximum valid input (after rounding) |
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Output for out-of-range negative input |
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Output for |
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Output for out-of-range positive input |
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Output for |
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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.
Decode Variables
Bits<5> fs1 = $encoding[19:15];
Bits<3> rm = $encoding[14:12];
Bits<5> xd = $encoding[11:7];Execution
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Pruned, XLEN == 64
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Original
check_f_ok($encoding);
RoundingMode rounding_mode = rm_to_mode(rm, $encoding);
X[xd] = $signed(f32_to_i32(F[fs1], rounding_mode));check_f_ok($encoding);
RoundingMode rounding_mode = rm_to_mode(rm, $encoding);
X[xd] = $signed(f32_to_i32(F[fs1], rounding_mode));