nx_tier_swap_demo.nx source

1// nx_tier_swap_demo.nx -- proof that nx_tier.nx swap is real. 2// 3// Computes the triangular sum 1 + 2 + ... + N where N is chosen 4// to overflow signed 32-bit int but fit signed 64-bit. 5// 6// sum(N) = N * (N+1) / 2 7// N = 100000 -> sum = 5,000,050,000 (~5e9) 8// int32 max = 2,147,483,647 (~2.1e9) -> overflows 9// int64 max = 9.2e18 -> fits 10// 11// With nx_int = i64: prints "5000050000" and exits 0 12// With nx_int = i32: would wrap to a negative number and exit 1 13// (after editing nx_tier.nx to swap the alias). 14// 15// Substrate-level proof that one edit to nx_tier.nx propagates. 16 17// nx_safety_envelope: 18// intended_use: AUTO_APPLIED -- primitive-specific tuning queued 19// sil_target: SIL1 20// evidence: [bulk_applied_2026-05-16, see-file-comment-for-detail] 21// verdict: NOT_YET_EVALUATED 22 23import "nx_syscalls.nx" 24import "nx_runtime.nx" 25import "nx_tier.nx" 26const K_MAGIC_100000: i64 = 100000 27const K_MAGIC_5000050000: i64 = 5000050000 28 29const STDOUT: i64 = 1 30 31func triangular_sum(n: nx_int) -> nx_int { 32 var sum: nx_int = 0 33 var i: nx_int = 1 34 while i <= n { 35 sum = sum + i 36 i = i + 1 37 } 38 return sum 39} 40 41func main() -> i64 { 42 let n: nx_int = K_MAGIC_100000 43 let s: nx_int = triangular_sum(n) 44 45 let label: *u8 = "triangular_sum(100000) with nx_int = " as *u8 46 sys_write(STDOUT, label, strlen(label)) 47 48 // Print the type's effective width by emitting whether the 49 // computation overflowed. Expected with i64: 5000050000. 50 print_i64(s) 51 let nl: *u8 = "\n" as *u8 52 sys_write(STDOUT, nl, 1) 53 54 if s == K_MAGIC_5000050000 { 55 let pass: *u8 = "PASS: nx_int holds N>=i32-overflow (>= i64)\n" as *u8 56 sys_write(STDOUT, pass, strlen(pass)) 57 return 0 58 } 59 let fail: *u8 = "FAIL/EXPECTED: nx_int wrapped (likely i32-aliased)\n" as *u8 60 sys_write(STDOUT, fail, strlen(fail)) 61 return 1 62}