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compiler-builtins-zynq
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start of __clzsi2

This commit is contained in:
Lokathor 2018-12-20 17:47:57 -07:00
parent 10f4f35f96
commit 3080360beb
1 changed files with 58 additions and 0 deletions
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58
src/arm.rs
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@ -233,3 +233,61 @@ pub unsafe extern "aapcs" fn __aeabi_memclr4(dest: *mut u8, n: usize) {
pub unsafe extern "aapcs" fn __aeabi_memclr8(dest: *mut u8, n: usize) {
__aeabi_memset4(dest, n, 0);
}
#[no_mangle]
#[cfg(any(target_pointer_width = "16", target_pointer_width = "32", target_pointer_width = "64"))]
pub extern "C" fn __clzsi2(mut x: usize) -> usize {
// TODO: const this? Requires const if
let mut y: usize;
let mut n: usize = {
#[cfg(target_pointer_width = "64")]
{
64
}
#[cfg(target_pointer_width = "32")]
{
32
}
#[cfg(target_pointer_width = "16")]
{
16
}
};
#[cfg(target_pointer_width = "64")]
{
y = x >> 32;
if y != 0 {
n -= 32;
x = y;
}
}
#[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
{
y = x >> 16;
if y != 0 {
n -= 16;
x = y;
}
}
y = x >> 8;
if y != 0 {
n -= 8;
x = y;
}
y = x >> 4;
if y != 0 {
n -= 4;
x = y;
}
y = x >> 2;
if y != 0 {
n -= 2;
x = y;
}
y = x >> 1;
if y != 0 {
n - 2
} else {
n - x
}
}