90 lines
1.7 KiB
Rust
90 lines
1.7 KiB
Rust
use std::simd::u64x2;
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use std::mem::{size_of, zeroed};
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use stack::Stack;
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extern "C" {
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#[link_name = "lwut_bootstrap"]
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pub fn bootstrap();
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#[link_name = "lwut_swapcontext"]
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pub fn swapcontext(save: *mut Registers, restore: *mut Registers);
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#[link_name = "lwut_get_sp_limit"]
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pub fn get_sp_limit() -> *const u8;
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#[link_name = "lwut_set_sp_limit"]
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pub fn set_sp_limit(limit: *const u8);
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#[link_name = "lwut_abort"]
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pub fn abort() -> !;
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}
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#[allow(non_camel_case_types)]
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pub type uintptr_t = u64;
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#[repr(C)]
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#[allow(dead_code)]
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pub struct Registers {
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rbx: u64,
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rsp: u64,
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rbp: u64,
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rdi: u64,
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r12: u64,
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r13: u64,
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r14: u64,
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r15: u64,
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ip: u64,
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xmm0: u64x2,
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xmm1: u64x2,
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xmm2: u64x2,
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xmm3: u64x2,
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xmm4: u64x2,
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xmm5: u64x2,
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}
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impl Registers {
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pub fn new() -> Registers {
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unsafe {
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Registers {
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ip: abort as u64,
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.. zeroed()
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}
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}
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}
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}
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pub fn initialise_call_frame(stack: &mut Stack, init: uintptr_t, args: &[uintptr_t]) -> Registers {
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let sp = stack.top() as *mut uintptr_t;
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let sp = align_down_mut(sp, 16);
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let sp = offset_mut(sp, -1);
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unsafe {
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*sp = 0;
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}
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let mut regs = Registers {
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rbp: 0,
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rsp: sp as uintptr_t,
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ip: bootstrap as uintptr_t,
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r12: init,
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.. Registers::new()
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};
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match into_fields!(regs { rdi, r13, r14, r15 } <- args.iter().cloned()) {
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Some(mut args) => if args.next().is_some() {
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panic!("too many arguments")
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},
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None => {}
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}
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regs
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}
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#[inline]
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fn align_down_mut<T>(sp: *mut T, n: uint) -> *mut T {
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let sp = (sp as uint) & !(n - 1);
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sp as *mut T
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}
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// ptr::offset_mmut is positive ints only
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#[inline]
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pub fn offset_mut<T>(ptr: *mut T, count: int) -> *mut T {
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(ptr as int + count * (size_of::<T>() as int)) as *mut T
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}
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