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allow comptime_int in math.shl and math.shr

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This commit is contained in:
Sahnvour 2019-06-09 14:44:41 +02:00
parent 10e33b3536
commit 8e0670198b
1 changed files with 11 additions and 5 deletions
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16
std/math.zig
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@ -288,10 +288,8 @@ pub fn shl(comptime T: type, a: T, shift_amt: var) T {
const abs_shift_amt = absCast(shift_amt);
const casted_shift_amt = if (abs_shift_amt >= T.bit_count) return 0 else @intCast(Log2Int(T), abs_shift_amt);
if (@typeOf(shift_amt).is_signed) {
if (shift_amt >= 0) {
return a << casted_shift_amt;
} else {
if (@typeOf(shift_amt) == comptime_int or @typeOf(shift_amt).is_signed) {
if (shift_amt < 0) {
return a >> casted_shift_amt;
}
}
@ -304,6 +302,10 @@ test "math.shl" {
testing.expect(shl(u8, 0b11111111, usize(8)) == 0);
testing.expect(shl(u8, 0b11111111, usize(9)) == 0);
testing.expect(shl(u8, 0b11111111, isize(-2)) == 0b00111111);
testing.expect(shl(u8, 0b11111111, 3) == 0b11111000);
testing.expect(shl(u8, 0b11111111, 8) == 0);
testing.expect(shl(u8, 0b11111111, 9) == 0);
testing.expect(shl(u8, 0b11111111, -2) == 0b00111111);
}
/// Shifts right. Overflowed bits are truncated.
@ -312,7 +314,7 @@ pub fn shr(comptime T: type, a: T, shift_amt: var) T {
const abs_shift_amt = absCast(shift_amt);
const casted_shift_amt = if (abs_shift_amt >= T.bit_count) return 0 else @intCast(Log2Int(T), abs_shift_amt);
if (@typeOf(shift_amt).is_signed) {
if (@typeOf(shift_amt) == comptime_int or @typeOf(shift_amt).is_signed) {
if (shift_amt >= 0) {
return a >> casted_shift_amt;
} else {
@ -328,6 +330,10 @@ test "math.shr" {
testing.expect(shr(u8, 0b11111111, usize(8)) == 0);
testing.expect(shr(u8, 0b11111111, usize(9)) == 0);
testing.expect(shr(u8, 0b11111111, isize(-2)) == 0b11111100);
testing.expect(shr(u8, 0b11111111, 3) == 0b00011111);
testing.expect(shr(u8, 0b11111111, 8) == 0);
testing.expect(shr(u8, 0b11111111, 9) == 0);
testing.expect(shr(u8, 0b11111111, -2) == 0b11111100);
}
/// Rotates right. Only unsigned values can be rotated.