4c16f9a3c3
This covers the majority of the functions as covered by the C99 specification for a math library. Code is adapted primarily from musl libc, with the pow and standard trigonometric functions adapted from the Go stdlib. Changes: - Remove assert expose in index and import as needed. - Add float log function and merge with existing base 2 integer implementation. See https://github.com/tiehuis/zig-fmath. See #374.
71 lines
1.4 KiB
Zig
71 lines
1.4 KiB
Zig
const math = @import("index.zig");
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const assert = @import("../debug.zig").assert;
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pub fn trunc(x: var) -> @typeOf(x) {
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const T = @typeOf(x);
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switch (T) {
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f32 => @inlineCall(trunc32, x),
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f64 => @inlineCall(trunc64, x),
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else => @compileError("trunc not implemented for " ++ @typeName(T)),
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}
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}
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fn trunc32(x: f32) -> f32 {
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const u = @bitCast(u32, x);
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var e = i32(((u >> 23) & 0xFF)) - 0x7F + 9;
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var m: u32 = undefined;
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if (e >= 23 + 9) {
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return x;
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}
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if (e < 9) {
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e = 1;
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}
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m = @maxValue(u32) >> u32(e);
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if (u & m == 0) {
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x
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} else {
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math.forceEval(x + 0x1p120);
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@bitCast(f32, u & ~m)
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}
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}
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fn trunc64(x: f64) -> f64 {
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const u = @bitCast(u64, x);
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var e = i32(((u >> 52) & 0x7FF)) - 0x3FF + 12;
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var m: u64 = undefined;
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if (e >= 52 + 12) {
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return x;
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}
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if (e < 12) {
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e = 1;
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}
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m = @maxValue(u64) >> u64(e);
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if (u & m == 0) {
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x
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} else {
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math.forceEval(x + 0x1p120);
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@bitCast(f64, u & ~m)
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}
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}
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test "trunc" {
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assert(trunc(f32(1.3)) == trunc32(1.3));
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assert(trunc(f64(1.3)) == trunc64(1.3));
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}
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test "trunc32" {
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assert(trunc32(1.3) == 1.0);
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assert(trunc32(-1.3) == -1.0);
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assert(trunc32(0.2) == 0.0);
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}
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test "trunc64" {
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assert(trunc64(1.3) == 1.0);
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assert(trunc64(-1.3) == -1.0);
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assert(trunc64(0.2) == 0.0);
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}
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