zig/lib/compiler_rt/cmp.zig

const std = @import("std");
const builtin = @import("builtin");
const is_test = builtin.is_test;
const common = @import("common.zig");

pub const panic = common.panic;

comptime {
    @export(__cmpsi2, .{ .name = "__cmpsi2", .linkage = common.linkage, .visibility = common.visibility });
    @export(__cmpdi2, .{ .name = "__cmpdi2", .linkage = common.linkage, .visibility = common.visibility });
    @export(__cmpti2, .{ .name = "__cmpti2", .linkage = common.linkage, .visibility = common.visibility });
    @export(__ucmpsi2, .{ .name = "__ucmpsi2", .linkage = common.linkage, .visibility = common.visibility });
    @export(__ucmpdi2, .{ .name = "__ucmpdi2", .linkage = common.linkage, .visibility = common.visibility });
    @export(__ucmpti2, .{ .name = "__ucmpti2", .linkage = common.linkage, .visibility = common.visibility });
}

// cmp - signed compare
// - cmpXi2_generic for unoptimized little and big endian

// ucmp - unsigned compare
// - ucmpXi2_generic for unoptimized little and big endian

// a <  b => 0
// a == b => 1
// a >  b => 2

inline fn XcmpXi2(comptime T: type, a: T, b: T) i32 {
    var cmp1: i32 = 0;
    var cmp2: i32 = 0;
    if (a > b)
        cmp1 = 1;
    if (a < b)
        cmp2 = 1;
    return cmp1 - cmp2 + 1;
}

pub fn __cmpsi2(a: i32, b: i32) callconv(.C) i32 {
    return XcmpXi2(i32, a, b);
}

pub fn __cmpdi2(a: i64, b: i64) callconv(.C) i32 {
    return XcmpXi2(i64, a, b);
}

pub fn __cmpti2(a: i128, b: i128) callconv(.C) i32 {
    return XcmpXi2(i128, a, b);
}

pub fn __ucmpsi2(a: u32, b: u32) callconv(.C) i32 {
    return XcmpXi2(u32, a, b);
}

pub fn __ucmpdi2(a: u64, b: u64) callconv(.C) i32 {
    return XcmpXi2(u64, a, b);
}

pub fn __ucmpti2(a: u128, b: u128) callconv(.C) i32 {
    return XcmpXi2(u128, a, b);
}

test {
    _ = @import("cmpsi2_test.zig");
    _ = @import("cmpdi2_test.zig");
    _ = @import("cmpti2_test.zig");

    _ = @import("ucmpsi2_test.zig");
    _ = @import("ucmpdi2_test.zig");
    _ = @import("ucmpti2_test.zig");
}