mirror of
https://github.com/ziglang/zig.git
synced 2024-12-03 18:38:45 +00:00
30f2bb8464
When we're compiling compiler_rt for any WebAssembly target, we do not want to expose all the compiler-rt functions to the host runtime. By setting the visibility of all exports to `hidden`, we allow the linker to resolve the symbols during linktime, while not expose the functions to the host runtime. This also means the linker can properly garbage collect any compiler-rt function that does not get resolved. The symbol visibility for all target remains the same as before: `default`.
80 lines
2.6 KiB
Zig
80 lines
2.6 KiB
Zig
const std = @import("std");
|
|
const builtin = @import("builtin");
|
|
const math = std.math;
|
|
const common = @import("common.zig");
|
|
|
|
pub const panic = common.panic;
|
|
|
|
comptime {
|
|
@export(__mulosi4, .{ .name = "__mulosi4", .linkage = common.linkage, .visibility = common.visibility });
|
|
@export(__mulodi4, .{ .name = "__mulodi4", .linkage = common.linkage, .visibility = common.visibility });
|
|
@export(__muloti4, .{ .name = "__muloti4", .linkage = common.linkage, .visibility = common.visibility });
|
|
}
|
|
|
|
// mulo - multiplication overflow
|
|
// * return a*%b.
|
|
// * return if a*b overflows => 1 else => 0
|
|
// - muloXi4_genericSmall as default
|
|
// - muloXi4_genericFast for 2*bitsize <= usize
|
|
|
|
inline fn muloXi4_genericSmall(comptime ST: type, a: ST, b: ST, overflow: *c_int) ST {
|
|
overflow.* = 0;
|
|
const min = math.minInt(ST);
|
|
var res: ST = a *% b;
|
|
// Hacker's Delight section Overflow subsection Multiplication
|
|
// case a=-2^{31}, b=-1 problem, because
|
|
// on some machines a*b = -2^{31} with overflow
|
|
// Then -2^{31}/-1 overflows and any result is possible.
|
|
// => check with a<0 and b=-2^{31}
|
|
if ((a < 0 and b == min) or (a != 0 and @divTrunc(res, a) != b))
|
|
overflow.* = 1;
|
|
return res;
|
|
}
|
|
|
|
inline fn muloXi4_genericFast(comptime ST: type, a: ST, b: ST, overflow: *c_int) ST {
|
|
overflow.* = 0;
|
|
const EST = switch (ST) {
|
|
i32 => i64,
|
|
i64 => i128,
|
|
i128 => i256,
|
|
else => unreachable,
|
|
};
|
|
const min = math.minInt(ST);
|
|
const max = math.maxInt(ST);
|
|
var res: EST = @as(EST, a) * @as(EST, b);
|
|
//invariant: -2^{bitwidth(EST)} < res < 2^{bitwidth(EST)-1}
|
|
if (res < min or max < res)
|
|
overflow.* = 1;
|
|
return @truncate(ST, res);
|
|
}
|
|
|
|
pub fn __mulosi4(a: i32, b: i32, overflow: *c_int) callconv(.C) i32 {
|
|
if (2 * @bitSizeOf(i32) <= @bitSizeOf(usize)) {
|
|
return muloXi4_genericFast(i32, a, b, overflow);
|
|
} else {
|
|
return muloXi4_genericSmall(i32, a, b, overflow);
|
|
}
|
|
}
|
|
|
|
pub fn __mulodi4(a: i64, b: i64, overflow: *c_int) callconv(.C) i64 {
|
|
if (2 * @bitSizeOf(i64) <= @bitSizeOf(usize)) {
|
|
return muloXi4_genericFast(i64, a, b, overflow);
|
|
} else {
|
|
return muloXi4_genericSmall(i64, a, b, overflow);
|
|
}
|
|
}
|
|
|
|
pub fn __muloti4(a: i128, b: i128, overflow: *c_int) callconv(.C) i128 {
|
|
if (2 * @bitSizeOf(i128) <= @bitSizeOf(usize)) {
|
|
return muloXi4_genericFast(i128, a, b, overflow);
|
|
} else {
|
|
return muloXi4_genericSmall(i128, a, b, overflow);
|
|
}
|
|
}
|
|
|
|
test {
|
|
_ = @import("mulosi4_test.zig");
|
|
_ = @import("mulodi4_test.zig");
|
|
_ = @import("muloti4_test.zig");
|
|
}
|