66bdc70bf1
Move examples/*.sx and their expected/ snapshots into per-category subfolders (examples/<category>/...). Folder = leading filename token, with ffi-objc/ffi-jni kept whole; filenames are unchanged. The corpus runner and LSP sweep now discover each category's expected/ dir, while issues/ stays flat. Example 1058's repo-root-relative companion import is made file-relative. Path strings embedded in 164 snapshots were regenerated (path-only changes). Test-layout docs in CLAUDE.md updated.
35 lines
1.3 KiB
Plaintext
35 lines
1.3 KiB
Plaintext
// Atomic($T) compare-exchange: compare_exchange / compare_exchange_weak → LLVM
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// cmpxchg. Result is `?T` — null = SUCCESS; a present value is the ACTUAL current
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// value on failure (for a retry loop). Stream A (atomics) A.2. Single-thread.
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#import "modules/std.sx";
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#import "modules/std/atomic.sx";
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main :: () {
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// Successful CAS: 10 == 10 → store 20, returns null.
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a := Atomic(i64).init(10);
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got := a.compare_exchange(10, 20, .acq_rel, .acquire);
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if got == null {
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print("cas ok, now: {}\n", a.load(.acquire)); // 20
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} else {
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print("cas unexpected fail: {}\n", got!);
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}
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// Failing CAS: 99 != 20 → no store, returns the actual value (20), unchanged.
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got2 := a.compare_exchange(99, 0, .seq_cst, .seq_cst);
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if got2 == null {
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print("cas unexpected ok\n");
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} else {
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print("cas failed, actual: {}, still: {}\n", got2!, a.load(.seq_cst)); // 20, 20
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}
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// Retry loop with the weak variant: increment a counter by 5.
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counter := Atomic(i64).init(100);
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cur := counter.load(.relaxed);
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while true {
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r := counter.compare_exchange_weak(cur, cur + 5, .acq_rel, .acquire);
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if r == null { break; }
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cur = r!; // retry with the observed value
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}
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print("after loop: {}\n", counter.load(.seq_cst)); // 105
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}
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