holey-bytes/hbvm/src/float/x86_64.rs
2024-02-03 20:08:09 +01:00

65 lines
1.9 KiB
Rust

use {
core::arch::{asm, x86_64 as arin},
hbbytecode::RoundingMode,
};
macro_rules! gen_op {
[$($ty:ident => $reg:ident),* $(,)?] => {
macro_rules! op {
$(
($ins:literal, $in:expr, $out:expr => $ty) => {
asm!(concat!($ins, " {}, {}"), out($reg) $out, in(xmm_reg) $in)
};
)*
}
};
}
gen_op![
f32 => xmm_reg,
f64 => xmm_reg,
i64 => reg,
];
macro_rules! fnsdef {
{$(
$(#[$attr:meta])*
$vis:vis fn $name:ident($from:ident -> $to:ident): $ins:literal;
)*} => {$(
$(#[$attr])*
$vis fn $name(val: $from, mode: RoundingMode) -> $to {
let result: $to;
unsafe {
let mut mxcsr = 0_u32;
'a: {
asm!("stmxcsr [{}]", in(reg) &mut mxcsr);
asm!(
"ldmxcsr [{}]",
in(reg) &(mxcsr & !arin::_MM_ROUND_MASK | match mode {
RoundingMode::NearestEven => break 'a,
RoundingMode::Truncate => arin::_MM_ROUND_TOWARD_ZERO,
RoundingMode::Up => arin::_MM_ROUND_UP,
RoundingMode::Down => arin::_MM_ROUND_DOWN,
})
);
}
op!($ins, val, result => $to);
// Set MXCSR to original value
asm!("ldmxcsr [{}]", in(reg) &mxcsr);
}
result
}
)*};
}
fnsdef! {
/// Convert [`f64`] to [`f32`] with chosen rounding mode
pub fn conv64to32(f64 -> f32): "cvtsd2ss";
/// Convert [`f32`] to [`i64`] with chosen rounding mode
pub fn f32toint(f32 -> i64): "cvttss2si";
/// Convert [`f64`] to [`i64`] with chosen rounding mode
pub fn f64toint(f64 -> i64): "cvttsd2si";
}