fcvt.s.w
Convert signed 32-bit integer to single-precision float
This instruction is defined by:
-
F, version >= 0
This instruction is included in the following profiles:
-
RVA20U64 (Mandatory)
-
RVA22U64 (Mandatory)
-
RVI20U32 (Optional)
-
RVI20U64 (Optional)
Synopsis
Converts a 32-bit signed integer in integer register rs1 into a floating-point number in floating-point register fd.
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 rd, 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> rs1 = $encoding[19:15];
Bits<3> rm = $encoding[14:12];
Bits<5> fd = $encoding[11:7];Execution
-
IDL
-
Sail
check_f_ok($encoding);
Bits<32> int_value = X[rs1];
Bits<1> sign = int_value[31];
RoundingMode rounding_mode = rm_to_mode(rm, $encoding);
if ((int_value & 32'h7fff_ffff) == 0) {
X[fd] = (sign == 1) ? packToF32UI(1, 0x9E, 0) : 0;
} else {
Bits<32> absA = (sign == 1) ? -int_value : int_value;
X[fd] = softfloat_normRoundPackToF32(sign, 0x9C, absA, rounding_mode);
}
mark_f_state_dirty();{
assert(sizeof(xlen) >= 64);
let rs1_val_LU = X(rs1)[63..0];
match (select_instr_or_fcsr_rm (rm)) {
None() => { handle_illegal(); RETIRE_FAIL },
Some(rm') => {
let rm_3b = encdec_rounding_mode(rm');
let (fflags, rd_val_S) = riscv_ui64ToF32 (rm_3b, rs1_val_LU);
accrue_fflags(fflags);
F_or_X_S(rd) = rd_val_S;
RETIRE_SUCCESS
}
}
}