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compiler-rt: Add __mulodi4

master
LemonBoy 2019-04-29 19:11:37 +02:00 committed by Andrew Kelley
parent d2328ac71a
commit b1a61a6d51
4 changed files with 131 additions and 0 deletions
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1
CMakeLists.txt
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@ -676,6 +676,7 @@ set(ZIG_STD_FILES
"special/compiler_rt/modti3.zig"
"special/compiler_rt/mulXf3.zig"
"special/compiler_rt/muloti4.zig"
"special/compiler_rt/mulodi4.zig"
"special/compiler_rt/multi3.zig"
"special/compiler_rt/negXf2.zig"
"special/compiler_rt/popcountdi2.zig"

1
std/special/compiler_rt.zig
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@ -221,6 +221,7 @@ comptime {
@export("__umodti3", @import("compiler_rt/umodti3.zig").__umodti3, linkage);
}
@export("__muloti4", @import("compiler_rt/muloti4.zig").__muloti4, linkage);
@export("__mulodi4", @import("compiler_rt/mulodi4.zig").__mulodi4, linkage);
}
const std = @import("std");

44
std/special/compiler_rt/mulodi4.zig Normal file
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@ -0,0 +1,44 @@
const builtin = @import("builtin");
const compiler_rt = @import("../compiler_rt.zig");
const maxInt = std.math.maxInt;
const minInt = std.math.minInt;
pub extern fn __mulodi4(a: i64, b: i64, overflow: *c_int) i64 {
@setRuntimeSafety(builtin.is_test);
const min = @bitCast(i64, u64(1 << (i64.bit_count - 1)));
const max = ~min;
overflow.* = 0;
const result = a *% b;
// Edge cases
if (a == min) {
if (b != 0 and b != 1) overflow.* = 1;
return result;
}
if (b == min) {
if (a != 0 and a != 1) overflow.* = 1;
return result;
}
// Take absolute value of a and b via abs(x) = (x^(x >> 63)) - (x >> 63).
const abs_a = (a ^ (a >> 63)) -% (a >> 63);
const abs_b = (b ^ (b >> 63)) -% (b >> 63);
// Unitary magnitude, cannot have overflow
if (abs_a < 2 or abs_b < 2) return result;
// Compare the signs of the operands
if ((a ^ b) >> 63 != 0) {
if (abs_a > @divTrunc(max, abs_b)) overflow.* = 1;
} else {
if (abs_a > @divTrunc(min, -abs_b)) overflow.* = 1;
}
return result;
}
test "import mulodi4" {
_ = @import("mulodi4_test.zig");
}

85
std/special/compiler_rt/mulodi4_test.zig Normal file
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@ -0,0 +1,85 @@
const __mulodi4 = @import("mulodi4.zig").__mulodi4;
const testing = @import("std").testing;
fn test__mulodi4(a: i64, b: i64, expected: i64, expected_overflow: c_int) void {
var overflow: c_int = undefined;
const x = __mulodi4(a, b, &overflow);
testing.expect(overflow == expected_overflow and (expected_overflow != 0 or x == expected));
}
test "mulodi4" {
test__mulodi4(0, 0, 0, 0);
test__mulodi4(0, 1, 0, 0);
test__mulodi4(1, 0, 0, 0);
test__mulodi4(0, 10, 0, 0);
test__mulodi4(10, 0, 0, 0);
test__mulodi4(0, 81985529216486895, 0, 0);
test__mulodi4(81985529216486895, 0, 0, 0);
test__mulodi4(0, -1, 0, 0);
test__mulodi4(-1, 0, 0, 0);
test__mulodi4(0, -10, 0, 0);
test__mulodi4(-10, 0, 0, 0);
test__mulodi4(0, -81985529216486895, 0, 0);
test__mulodi4(-81985529216486895, 0, 0, 0);
test__mulodi4(1, 1, 1, 0);
test__mulodi4(1, 10, 10, 0);
test__mulodi4(10, 1, 10, 0);
test__mulodi4(1, 81985529216486895, 81985529216486895, 0);
test__mulodi4(81985529216486895, 1, 81985529216486895, 0);
test__mulodi4(1, -1, -1, 0);
test__mulodi4(1, -10, -10, 0);
test__mulodi4(-10, 1, -10, 0);
test__mulodi4(1, -81985529216486895, -81985529216486895, 0);
test__mulodi4(-81985529216486895, 1, -81985529216486895, 0);
test__mulodi4(3037000499, 3037000499, 9223372030926249001, 0);
test__mulodi4(-3037000499, 3037000499, -9223372030926249001, 0);
test__mulodi4(3037000499, -3037000499, -9223372030926249001, 0);
test__mulodi4(-3037000499, -3037000499, 9223372030926249001, 0);
test__mulodi4(4398046511103, 2097152, 9223372036852678656, 0);
test__mulodi4(-4398046511103, 2097152, -9223372036852678656, 0);
test__mulodi4(4398046511103, -2097152, -9223372036852678656, 0);
test__mulodi4(-4398046511103, -2097152, 9223372036852678656, 0);
test__mulodi4(2097152, 4398046511103, 9223372036852678656, 0);
test__mulodi4(-2097152, 4398046511103, -9223372036852678656, 0);
test__mulodi4(2097152, -4398046511103, -9223372036852678656, 0);
test__mulodi4(-2097152, -4398046511103, 9223372036852678656, 0);
test__mulodi4(0x7FFFFFFFFFFFFFFF, -2, 2, 1);
test__mulodi4(-2, 0x7FFFFFFFFFFFFFFF, 2, 1);
test__mulodi4(0x7FFFFFFFFFFFFFFF, -1, @bitCast(i64, u64(0x8000000000000001)), 0);
test__mulodi4(-1, 0x7FFFFFFFFFFFFFFF, @bitCast(i64, u64(0x8000000000000001)), 0);
test__mulodi4(0x7FFFFFFFFFFFFFFF, 0, 0, 0);
test__mulodi4(0, 0x7FFFFFFFFFFFFFFF, 0, 0);
test__mulodi4(0x7FFFFFFFFFFFFFFF, 1, 0x7FFFFFFFFFFFFFFF, 0);
test__mulodi4(1, 0x7FFFFFFFFFFFFFFF, 0x7FFFFFFFFFFFFFFF, 0);
test__mulodi4(0x7FFFFFFFFFFFFFFF, 2, @bitCast(i64, u64(0x8000000000000001)), 1);
test__mulodi4(2, 0x7FFFFFFFFFFFFFFF, @bitCast(i64, u64(0x8000000000000001)), 1);
test__mulodi4(@bitCast(i64, u64(0x8000000000000000)), -2, @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(-2, @bitCast(i64, u64(0x8000000000000000)), @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(@bitCast(i64, u64(0x8000000000000000)), -1, @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(-1, @bitCast(i64, u64(0x8000000000000000)), @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(@bitCast(i64, u64(0x8000000000000000)), 0, 0, 0);
test__mulodi4(0, @bitCast(i64, u64(0x8000000000000000)), 0, 0);
test__mulodi4(@bitCast(i64, u64(0x8000000000000000)), 1, @bitCast(i64, u64(0x8000000000000000)), 0);
test__mulodi4(1, @bitCast(i64, u64(0x8000000000000000)), @bitCast(i64, u64(0x8000000000000000)), 0);
test__mulodi4(@bitCast(i64, u64(0x8000000000000000)), 2, @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(2, @bitCast(i64, u64(0x8000000000000000)), @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(@bitCast(i64, u64(0x8000000000000001)), -2, @bitCast(i64, u64(0x8000000000000001)), 1);
test__mulodi4(-2, @bitCast(i64, u64(0x8000000000000001)), @bitCast(i64, u64(0x8000000000000001)), 1);
test__mulodi4(@bitCast(i64, u64(0x8000000000000001)), -1, 0x7FFFFFFFFFFFFFFF, 0);
test__mulodi4(-1, @bitCast(i64, u64(0x8000000000000001)), 0x7FFFFFFFFFFFFFFF, 0);
test__mulodi4(@bitCast(i64, u64(0x8000000000000001)), 0, 0, 0);
test__mulodi4(0, @bitCast(i64, u64(0x8000000000000001)), 0, 0);
test__mulodi4(@bitCast(i64, u64(0x8000000000000001)), 1, @bitCast(i64, u64(0x8000000000000001)), 0);
test__mulodi4(1, @bitCast(i64, u64(0x8000000000000001)), @bitCast(i64, u64(0x8000000000000001)), 0);
test__mulodi4(@bitCast(i64, u64(0x8000000000000001)), 2, @bitCast(i64, u64(0x8000000000000000)), 1);
test__mulodi4(2, @bitCast(i64, u64(0x8000000000000001)), @bitCast(i64, u64(0x8000000000000000)), 1);
}