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unifying equality: fix senior_pointer_first

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This commit is contained in:
Edward Amsden 2023-10-03 16:28:09 -05:00
parent 4dd009c04c
commit e988b96341
1 changed files with 58 additions and 44 deletions
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102
rust/ares/src/mem.rs
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@ -746,8 +746,8 @@ pub unsafe fn unifying_equality(stack: &mut NockStack, a: *mut Noun, b: *mut Nou
}
}
(Right(x_cell), Right(y_cell)) => {
let x_as_ptr = x_cell.to_raw_pointer();
let y_as_ptr = y_cell.to_raw_pointer();
let x_as_ptr = x_cell.to_raw_pointer() as *const u64;
let y_as_ptr = y_cell.to_raw_pointer() as *const u64;
if x_cell.head().raw_equals(y_cell.head())
&& x_cell.tail().raw_equals(y_cell.tail())
{
@ -788,26 +788,20 @@ pub unsafe fn unifying_equality(stack: &mut NockStack, a: *mut Noun, b: *mut Nou
(*a).raw_equals(*b)
}
unsafe fn senior_pointer_first<T>(
unsafe fn senior_pointer_first(
stack: &NockStack,
a: *const T,
b: *const T,
) -> (*const T, *const T) {
let mut frame_pointer = stack.frame_pointer as *const u64;
let mut stack_pointer = stack.stack_pointer as *const u64;
let mut alloc_pointer = stack.alloc_pointer as *const u64;
let prev_stack_pointer = *(stack.prev_stack_pointer_pointer()) as *const u64;
a: *const u64,
b: *const u64,
) -> (*const u64, *const u64) {
let mut frame_pointer: *const u64 = stack.frame_pointer;
let mut stack_pointer: *const u64 = stack.stack_pointer;
let mut alloc_pointer: *const u64 = stack.alloc_pointer;
let prev_stack_pointer = *(stack.prev_stack_pointer_pointer());
let (mut high_pointer, mut low_pointer) = if stack.is_west() {
(
prev_stack_pointer as *const T,
(stack.alloc_pointer as *const T),
)
let (mut high_pointer, mut low_pointer): (*const u64, *const u64) = if stack.is_west() {
(prev_stack_pointer, alloc_pointer)
} else {
(
stack.alloc_pointer as *const T,
prev_stack_pointer as *const T,
)
(alloc_pointer, prev_stack_pointer)
};
loop {
@ -815,37 +809,57 @@ unsafe fn senior_pointer_first<T>(
a < high_pointer && a >= low_pointer,
b < high_pointer && b >= low_pointer,
) {
(true, true) => break (a, b), // both pointers are in the same frame, pick arbitrarily
(true, true) => {
// both pointers are in the same frame, pick arbitrarily (lower in mem)
if a < b {
break (a, b);
} else {
break (b, a);
};
}
(true, false) => break (b, a), // a is in the frame, b is not, so b is senior
(false, true) => break (a, b), // b is in the frame, a is not, so a is senior
(false, false) => {
// chase up the stack
#[allow(clippy::comparison_chain)]
if frame_pointer.is_null() {
// we found the top of the stack
break (a, b); // both are in the bottom frame, pick arbitrarily
// test to see if the frame under consideration is a west frame
if stack_pointer < alloc_pointer {
stack_pointer = *(frame_pointer.sub(STACK + 1)) as *const u64;
alloc_pointer = *(frame_pointer.sub(ALLOC + 1)) as *const u64;
frame_pointer = *(frame_pointer.sub(FRAME + 1)) as *const u64;
if frame_pointer.is_null() {
if a < b {
break (a, b);
} else {
break (b, a);
}
};
// previous allocation pointer
high_pointer = alloc_pointer;
// "previous previous" stack pointer. this is the other boundary of the previous allocation arena
low_pointer = *(frame_pointer.add(STACK)) as *const u64;
continue;
} else if stack_pointer > alloc_pointer {
stack_pointer = *(frame_pointer.add(STACK)) as *const u64;
alloc_pointer = *(frame_pointer.add(ALLOC)) as *const u64;
frame_pointer = *(frame_pointer.add(FRAME)) as *const u64;
if frame_pointer.is_null() {
if a < b {
break (a, b);
} else {
break (b, a);
}
};
// previous allocation pointer
low_pointer = alloc_pointer;
// "previous previous" stack pointer. this is the other boundary of the previous allocation arena
high_pointer = *(frame_pointer.sub(STACK + 1)) as *const u64;
} else {
// test to see if the frame under consideration is a west frame
if stack_pointer < alloc_pointer {
stack_pointer = *(frame_pointer.sub(STACK + 1)) as *const u64;
alloc_pointer = *(frame_pointer.sub(ALLOC + 1)) as *const u64;
frame_pointer = *(frame_pointer.sub(FRAME + 1)) as *const u64;
// previous allocation pointer
high_pointer = alloc_pointer as *const T;
// "previous previous" stack pointer. this is the other boundary of the previous allocation arena
low_pointer = (frame_pointer.add(STACK)) as *const T;
continue;
} else if stack_pointer > alloc_pointer {
stack_pointer = *(frame_pointer.add(STACK)) as *const u64;
alloc_pointer = *(frame_pointer.add(ALLOC)) as *const u64;
frame_pointer = *(frame_pointer.add(FRAME)) as *const u64;
// previous allocation pointer
low_pointer = alloc_pointer as *const T;
// "previous previous" stack pointer. this is the other boundary of the previous allocation arena
high_pointer = (frame_pointer.sub(STACK + 1)) as *const T;
} else {
panic!("senior_pointer_first: stack_pointer == alloc_pointer");
}
panic!("senior_pointer_first: stack_pointer == alloc_pointer");
}
}
}