61 lines
1.4 KiB
Rust
61 lines
1.4 KiB
Rust
//! misa register
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use core::num::NonZeroUsize;
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/// misa register
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#[derive(Clone, Copy, Debug)]
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pub struct Misa {
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bits: NonZeroUsize,
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}
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/// Machine XLEN
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#[derive(Copy, Clone, Debug, Eq, PartialEq)]
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pub enum MXL {
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XLEN32,
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XLEN64,
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XLEN128,
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}
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impl Misa {
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/// Returns the contents of the register as raw bits
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pub fn bits(&self) -> usize {
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self.bits.get()
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}
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/// Returns the machine xlen.
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pub fn mxl(&self) -> MXL {
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let value = match () {
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#[cfg(target_pointer_width = "32")]
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() => (self.bits() >> 30) as u8,
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#[cfg(target_pointer_width = "64")]
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() => (self.bits() >> 62) as u8,
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};
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match value {
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1 => MXL::XLEN32,
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2 => MXL::XLEN64,
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3 => MXL::XLEN128,
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_ => unreachable!(),
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}
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}
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/// Returns true when the atomic extension is implemented.
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pub fn has_extension(&self, extension: char) -> bool {
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let bit = extension as u8 - 65;
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if bit > 25 {
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return false;
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}
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self.bits() & (1 << bit) == (1 << bit)
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}
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}
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read_csr!(0x301, __read_misa);
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/// Reads the CSR
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#[inline]
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pub fn read() -> Option<Misa> {
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let r = unsafe{ _read() };
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// When misa is hardwired to zero it means that the misa csr
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// isn't implemented.
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NonZeroUsize::new(r).map(|bits| Misa { bits })
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}
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