Function from_int 

pub fn from_int(v: i64, f: Format, mode: Rounding) -> Rounded

Convert a two’s-complement integer to f, honoring mode.

An integer is sign × |v| × 2^0, so this is round_pack with a zero exponent and no sticky bit — which is the whole point of routing it here rather than through a Rust as cast. as rounds to nearest-even unconditionally, so CVT.S.W of a value needing more than 24 significand bits ignored FCSR.RM entirely: n64-systemtest converts 1234567891 under round-toward-zero and expects 0x4E93_2C05, where nearest-even gives 0x4E93_2C06.

The result cannot overflow (no integer exceeds the largest finite f64, and an i64 fits inside f32’s range) and cannot be subnormal, so inexact is the only flag it can raise.