fxsr.rs.html -- source
Description: Source to the Rust file `src/libcore/../stdsimd/crates/core_arch/src/x86_64/fxsr.rs`.
Keywords: rust, rustlang, rust-lang

      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112

    //! FXSR floating-point context fast save and restor.

    #[cfg(test)]
    use stdsimd_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://software.intel.com/sites/landingpage/IntrinsicsGuide/#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://software.intel.com/sites/landingpage/IntrinsicsGuide/#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 core_arch::x86_64::*;
        use std::{cmp::PartialEq, fmt};
        use stdsimd_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);
        }
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)