| //! FXSR floating-point context fast save and restore. |
| |
| #[cfg(test)] |
| use stdarch_test::assert_instr; |
| |
| #[allow(improper_ctypes)] |
| extern "C" { |
| #[link_name = "llvm.x86.fxsave64"] |
| fn fxsave64(p: *mut u8); |
| #[link_name = "llvm.x86.fxrstor64"] |
| fn fxrstor64(p: *const u8); |
| } |
| |
| /// Saves the `x87` FPU, `MMX` technology, `XMM`, and `MXCSR` registers to the |
| /// 512-byte-long 16-byte-aligned memory region `mem_addr`. |
| /// |
| /// A misaligned destination operand raises a general-protection (#GP) or an |
| /// alignment check exception (#AC). |
| /// |
| /// See [`FXSAVE`][fxsave] and [`FXRSTOR`][fxrstor]. |
| /// |
| /// [fxsave]: http://www.felixcloutier.com/x86/FXSAVE.html |
| /// [fxrstor]: http://www.felixcloutier.com/x86/FXRSTOR.html |
| /// |
| /// [Intel's documentation](https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_fxsave64) |
| #[inline] |
| #[target_feature(enable = "fxsr")] |
| #[cfg_attr(test, assert_instr(fxsave64))] |
| #[stable(feature = "simd_x86", since = "1.27.0")] |
| pub unsafe fn _fxsave64(mem_addr: *mut u8) { |
| fxsave64(mem_addr) |
| } |
| |
| /// Restores the `XMM`, `MMX`, `MXCSR`, and `x87` FPU registers from the |
| /// 512-byte-long 16-byte-aligned memory region `mem_addr`. |
| /// |
| /// The contents of this memory region should have been written to by a |
| /// previous |
| /// `_fxsave` or `_fxsave64` intrinsic. |
| /// |
| /// A misaligned destination operand raises a general-protection (#GP) or an |
| /// alignment check exception (#AC). |
| /// |
| /// See [`FXSAVE`][fxsave] and [`FXRSTOR`][fxrstor]. |
| /// |
| /// [fxsave]: http://www.felixcloutier.com/x86/FXSAVE.html |
| /// [fxrstor]: http://www.felixcloutier.com/x86/FXRSTOR.html |
| /// |
| /// [Intel's documentation](https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_fxrstor64) |
| #[inline] |
| #[target_feature(enable = "fxsr")] |
| #[cfg_attr(test, assert_instr(fxrstor64))] |
| #[stable(feature = "simd_x86", since = "1.27.0")] |
| pub unsafe fn _fxrstor64(mem_addr: *const u8) { |
| fxrstor64(mem_addr) |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use crate::core_arch::x86_64::*; |
| use std::{cmp::PartialEq, fmt}; |
| use stdarch_test::simd_test; |
| |
| #[repr(align(16))] |
| struct FxsaveArea { |
| data: [u8; 512], // 512 bytes |
| } |
| |
| impl FxsaveArea { |
| fn new() -> FxsaveArea { |
| FxsaveArea { data: [0; 512] } |
| } |
| fn ptr(&mut self) -> *mut u8 { |
| &mut self.data[0] as *mut _ as *mut u8 |
| } |
| } |
| |
| impl PartialEq<FxsaveArea> for FxsaveArea { |
| fn eq(&self, other: &FxsaveArea) -> bool { |
| for i in 0..self.data.len() { |
| if self.data[i] != other.data[i] { |
| return false; |
| } |
| } |
| true |
| } |
| } |
| |
| impl fmt::Debug for FxsaveArea { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| write!(f, "[")?; |
| for i in 0..self.data.len() { |
| write!(f, "{}", self.data[i])?; |
| if i != self.data.len() - 1 { |
| write!(f, ", ")?; |
| } |
| } |
| write!(f, "]") |
| } |
| } |
| |
| #[simd_test(enable = "fxsr")] |
| unsafe fn fxsave64() { |
| let mut a = FxsaveArea::new(); |
| let mut b = FxsaveArea::new(); |
| |
| fxsr::_fxsave64(a.ptr()); |
| fxsr::_fxrstor64(a.ptr()); |
| fxsr::_fxsave64(b.ptr()); |
| assert_eq!(a, b); |
| } |
| } |