mirror of
https://codeberg.org/ziglang/zig.git
synced 2026-04-27 19:09:47 +03:00
Alex Rønne Petersen
7ea8f842bc
Before: * test-zigc: run libzigc unit tests (part of test-modules) * test-libc: run libc-test cases Now: * test-libc: run libc API unit tests (part of test-modules) * test-libc-nsz: run libc-test cases libc API unit tests (previously referred to as libzigc unit tests) now run for all supported targets, even those we don't provide libzigc for. The idea is that this will help us catch bad assumptions in the unit tests, as well as bugs in other libcs. I considered this setup: * test-c: run libc API unit tests (part of test-modules) * test-libc-nsz: run libc-test cases * test-libc: both of the above However, I do not like it because it gives a false sense of security; the full module and C ABI test suites are still liable to catch libzigc bugs that test-c and test-libc-nsz might not. So contributors should just run the test steps outlined in https://codeberg.org/ziglang/zig/issues/30978. Co-authored-by: rpkak <rpkak@noreply.codeberg.org>
93 lines
3.8 KiB
Zig
93 lines
3.8 KiB
Zig
//! drand48 functions are based off a 48-bit lcg prng: https://pubs.opengroup.org/onlinepubs/9799919799/functions/drand48.html
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const builtin = @import("builtin");
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const std = @import("std");
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const Lcg = std.Random.lcg.Wrapping(u48);
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const symbol = @import("../../c.zig").symbol;
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comptime {
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if (builtin.target.isMuslLibC() or builtin.target.isWasiLibC()) {
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symbol(&erand48, "erand48");
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symbol(&jrand48, "jrand48");
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symbol(&nrand48, "nrand48");
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symbol(&drand48, "drand48");
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symbol(&lrand48, "lrand48");
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symbol(&mrand48, "mrand48");
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symbol(&lcong48, "lcong48");
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symbol(&seed48, "seed48");
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symbol(&srand48, "srand48");
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}
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}
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// NOTE: all "magic" numbers and tests are extracted and adapted from the source above
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const default_multiplier = 0x5DEECE66D;
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const default_addend = 0xB;
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var lcg: Lcg = .init(0, default_multiplier, default_addend);
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var seed48_xi: [3]c_ushort = undefined;
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fn erand48(xsubi: *[3]c_ushort) callconv(.c) f64 {
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const xi = @as(u48, @as(u16, @truncate(xsubi[0])) | (@as(u48, @as(u16, @truncate(xsubi[1])))) << 16) | (@as(u48, @as(u16, @truncate(xsubi[2]))) << 32);
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var separate_lcg: Lcg = .init(xi, lcg.a, lcg.c);
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const next_xi = separate_lcg.next();
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xsubi.* = .{ @truncate(next_xi & 0xFFFF), @truncate((next_xi >> 16) & 0xFFFF), @truncate((next_xi >> 32) & 0xFFFF) };
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return @as(f64, @bitCast(0x3ff0000000000000 | (@as(u64, next_xi) << 4))) - 1.0;
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}
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fn jrand48(xsubi: *[3]c_ushort) callconv(.c) c_long {
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const xi = @as(u48, @as(u16, @truncate(xsubi[0])) | (@as(u48, @as(u16, @truncate(xsubi[1])))) << 16) | (@as(u48, @as(u16, @truncate(xsubi[2]))) << 32);
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var separate_lcg: Lcg = .init(xi, lcg.a, lcg.c);
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const next_xi = separate_lcg.next();
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xsubi.* = .{ @truncate(next_xi & 0xFFFF), @truncate((next_xi >> 16) & 0xFFFF), @truncate((next_xi >> 32) & 0xFFFF) };
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return @as(i32, @bitCast(@as(u32, @truncate(next_xi >> 16))));
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}
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fn nrand48(xsubi: *[3]c_ushort) callconv(.c) c_long {
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const xi = @as(u48, @as(u16, @truncate(xsubi[0])) | (@as(u48, @as(u16, @truncate(xsubi[1])))) << 16) | (@as(u48, @as(u16, @truncate(xsubi[2]))) << 32);
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var separate_lcg: Lcg = .init(xi, lcg.a, lcg.c);
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const next_xi = separate_lcg.next();
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xsubi.* = .{ @truncate(next_xi & 0xFFFF), @truncate((next_xi >> 16) & 0xFFFF), @truncate((next_xi >> 32) & 0xFFFF) };
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return @intCast(next_xi >> 17); // a c_long is always at least 32-bits, this is never UB
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}
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fn drand48() callconv(.c) f64 {
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return @as(f64, @bitCast(0x3ff0000000000000 | (@as(u64, lcg.next()) << 4))) - 1.0;
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}
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fn lrand48() callconv(.c) c_long {
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return @intCast(lcg.next() >> 17);
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}
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fn mrand48() callconv(.c) c_long {
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return @as(i32, @bitCast(@as(u32, @truncate(lcg.next() >> 16))));
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}
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// 0..3 is `Xi`, 3..6 is `a`, 6 is `c`
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// first low 16-bits, then mid, then high.
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fn lcong48(param: *[7]c_ushort) callconv(.c) void {
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lcg.xi = (@as(u48, @as(u16, @truncate(param[0]))) | (@as(u48, @as(u16, @truncate(param[1])))) << 16) | (@as(u48, @as(u16, @truncate(param[2]))) << 32);
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lcg.a = (@as(u48, @as(u16, @truncate(param[3]))) | (@as(u48, @as(u16, @truncate(param[4])))) << 16) | (@as(u48, @as(u16, @truncate(param[5]))) << 32);
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lcg.c = @as(u16, @truncate(param[6]));
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}
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fn seed48(seed16v: *[3]c_ushort) callconv(.c) *[3]c_ushort {
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seed48_xi = .{ @truncate(lcg.xi & 0xFFFF), @truncate((lcg.xi >> 16) & 0xFFFF), @truncate((lcg.xi >> 32) & 0xFFFF) };
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const xi = (@as(u48, @as(u16, @truncate(seed16v[0]))) | (@as(u48, @as(u16, @truncate(seed16v[1])))) << 16) | (@as(u48, @as(u16, @truncate(seed16v[2]))) << 32);
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lcg = .init(xi, default_multiplier, default_addend);
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return &seed48_xi;
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}
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fn srand48(seedval: c_long) callconv(.c) void {
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const xi = (@as(u32, @truncate(@as(c_ulong, @bitCast(seedval)))) << 16) | 0x330E;
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lcg = .init(xi, default_multiplier, default_addend);
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}
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