| // Copyright (C) 2019 Tiancheng "Timothy" Gu. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| /*--- |
| esid: sec-math.fround |
| description: Math.fround should use roundTiesToEven for conversion to binary32. |
| ---*/ |
| |
| // We test five values against Math.fround, with their binary64 representation |
| // shown: |
| // a0 := 1.0 = 0x1p+0 |
| // a1 := 1.0000000596046448 = 0x1.000001p+0 |
| // a2 := 1.0000001192092896 = 0x1.000002p+0 |
| // a3 := 1.0000001788139343 = 0x1.000003p+0 |
| // a4 := 1.000000238418579 = 0x1.000004p+0 |
| // a5 := 1.0000002980232239 = 0x1.000005p+0 |
| // a6 := 1.0000003576278687 = 0x1.000006p+0 |
| // (Note: they are separated by 2 ** -24.) |
| // |
| // a0, a2, a4, and a6 are all representable exactly in binary32; however, while |
| // a0 and a4 have even mantissas in binary32, a2 and a6 have an odd mantissa |
| // when represented in that way. |
| // |
| // a1 is exactly halfway between a0 and a2, a3 between a2 and a4, and a5 |
| // between a4 and a6. By roundTiesToEven, Math.fround should favor a0 and a4 |
| // over a2 when they are equally close, and a4 over a6 when they are equally |
| // close. |
| |
| var a0 = 1.0; |
| var a1 = 1.0000000596046448; |
| var a2 = 1.0000001192092896; |
| var a3 = 1.0000001788139343; |
| var a4 = 1.000000238418579; |
| var a5 = 1.0000002980232239; |
| var a6 = 1.0000003576278687; |
| |
| assert.sameValue(Math.fround(a0), a0, 'Math.fround(a0)'); |
| assert.sameValue(Math.fround(a1), a0, 'Math.fround(a1)'); |
| assert.sameValue(Math.fround(a2), a2, 'Math.fround(a2)'); |
| assert.sameValue(Math.fround(a3), a4, 'Math.fround(a3)'); |
| assert.sameValue(Math.fround(a4), a4, 'Math.fround(a4)'); |
| assert.sameValue(Math.fround(a5), a4, 'Math.fround(a5)'); |
| assert.sameValue(Math.fround(a6), a6, 'Math.fround(a6)'); |
| |
| assert.sameValue(Math.fround(-a0), -a0, 'Math.fround(-a0)'); |
| assert.sameValue(Math.fround(-a1), -a0, 'Math.fround(-a1)'); |
| assert.sameValue(Math.fround(-a2), -a2, 'Math.fround(-a2)'); |
| assert.sameValue(Math.fround(-a3), -a4, 'Math.fround(-a3)'); |
| assert.sameValue(Math.fround(-a4), -a4, 'Math.fround(-a4)'); |
| assert.sameValue(Math.fround(-a5), -a4, 'Math.fround(-a5)'); |
| assert.sameValue(Math.fround(-a6), -a6, 'Math.fround(-a6)'); |