90 lines
1.9 KiB
Zig
90 lines
1.9 KiB
Zig
const builtin = @import("builtin");
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const math = @import("index.zig");
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const assert = @import("../debug.zig").assert;
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pub fn ceil(x: var) -> @typeOf(x) {
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const T = @typeOf(x);
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switch (T) {
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f32 => @inlineCall(ceil32, x),
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f64 => @inlineCall(ceil64, x),
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else => @compileError("ceil not implemented for " ++ @typeName(T)),
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}
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}
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fn ceil32(x: f32) -> f32 {
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var u = @bitCast(u32, x);
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var e = i32((u >> 23) & 0xFF) - 0x7F;
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var m: u32 = undefined;
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if (e >= 23) {
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return x;
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}
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else if (e >= 0) {
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m = 0x007FFFFF >> u32(e);
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if (u & m == 0) {
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return x;
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}
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math.forceEval(x + 0x1.0p120);
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if (u >> 31 == 0) {
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u += m;
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}
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u &= ~m;
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@bitCast(f32, u)
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} else {
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math.forceEval(x + 0x1.0p120);
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if (u >> 31 != 0) {
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return -0.0;
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} else {
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1.0
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}
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}
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}
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fn ceil64(x: f64) -> f64 {
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const u = @bitCast(u64, x);
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const e = (u >> 52) & 0x7FF;
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var y: f64 = undefined;
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if (e >= 0x3FF+52 or x == 0) {
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return x;
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}
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if (u >> 63 != 0) {
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@setFloatMode(this, builtin.FloatMode.Strict);
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y = x - math.f64_toint + math.f64_toint - x;
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} else {
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@setFloatMode(this, builtin.FloatMode.Strict);
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y = x + math.f64_toint - math.f64_toint - x;
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}
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if (e <= 0x3FF-1) {
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math.forceEval(y);
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if (u >> 63 != 0) {
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return -0.0; // Compiler requires return.
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} else {
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1.0
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}
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} else if (y < 0) {
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x + y + 1
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} else {
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x + y
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}
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}
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test "ceil" {
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assert(ceil(f32(0.0)) == ceil32(0.0));
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assert(ceil(f64(0.0)) == ceil64(0.0));
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}
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test "ceil32" {
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assert(ceil32(1.3) == 2.0);
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assert(ceil32(-1.3) == -1.0);
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assert(ceil32(0.2) == 1.0);
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}
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test "ceil64" {
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assert(ceil64(1.3) == 2.0);
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assert(ceil64(-1.3) == -1.0);
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assert(ceil64(0.2) == 1.0);
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}
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