holey-bytes/vm/src/float/aarch64.rs

47 lines
1.5 KiB
Rust

use {core::arch::asm, hbbytecode::RoundingMode};
macro_rules! fnsdef {
{$(
$(#[$attr:meta])*
$vis:vis fn $name:ident[$inreg:ident -> $outreg:ident]($from:ident -> $to:ident): $ins:literal;
)*} => {$(
$(#[$attr])*
$vis fn $name(val: $from, mode: RoundingMode) -> $to {
let result: $to;
unsafe {
let fpcr: u64;
unsafe { asm!("mrs {}, fpcr", out(reg) fpcr) };
let fpcr_new = fpcr & !(0b11 << 22)
| (match mode {
RoundingMode::NearestEven => 0b00,
RoundingMode::Truncate => 0b11,
RoundingMode::Up => 0b01,
RoundingMode::Down => 0b10,
}) << 22;
unsafe { asm!("msr fpcr, {}", in(reg) fpcr_new) };
asm!(
$ins,
out($outreg) result,
in($inreg) val,
);
unsafe { asm!("msr fpcr, {}", in(reg) fpcr) };
}
result
}
)*};
}
fnsdef! {
/// Convert [`f64`] to [`f32`] with chosen rounding mode
pub fn conv64to32[vreg -> vreg](f64 -> f32): "fcvt {:s}, {:d}";
/// Convert [`f32`] to [`i64`] with chosen rounding mode
pub fn f32toint[vreg -> reg](f32 -> i64): "fcvtzs {}, {:s}";
/// Convert [`f64`] to [`i64`] with chosen rounding mode
pub fn f64toint[vreg -> reg](f64 -> i64): "fcvtzs {}, {:d}";
}