From 2e675142dd269348da992c1862a28e56e0a87eb6 Mon Sep 17 00:00:00 2001 From: Jan Mercl <0xjnml@gmail.com> Date: Wed, 14 Sep 2016 13:17:37 +0200 Subject: [PATCH] test/float_lit2: fix expressions in comment The change corrects the values of the largest float32 value (f1) and the value of the halfway point between f1 and the next, overflow value (f2). Fixes #17012 Change-Id: Idaf9997b69d61fafbffdb980d751c9857732e14d Reviewed-on: https://go-review.googlesource.com/29171 Reviewed-by: Robert Griesemer --- test/float_lit2.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/test/float_lit2.go b/test/float_lit2.go index bb86559a37f..901698f8a40 100644 --- a/test/float_lit2.go +++ b/test/float_lit2.go @@ -13,12 +13,12 @@ import ( "math" ) -// The largest exact float32 is f₁ = (1+(1-2²³))×2¹²⁷ = (1-2²⁴)×2¹²⁸ = 2¹²⁸ - 2¹⁰⁴. +// The largest exact float32 is f₁ = (1+1-1/2²³)×2¹²⁷ = (2-2⁻²³)×2¹²⁷ = 2¹²⁸ - 2¹⁰⁴. // The next float32 would be f₂ = (1+1)×2¹²⁷ = 1×2¹²⁸, except that exponent is out of range. // Float32 conversion rounds to the nearest float32, rounding to even mantissa: // between f₁ and f₂, values closer to f₁ round to f₁ and values closer to f₂ are rejected as out of range. // f₁ is an odd mantissa, so the halfway point (f₁+f₂)/2 rounds to f₂ and is rejected. -// The halfway point is (f₁+f₂)/2 = 2¹²⁸ - 2¹⁰⁵. +// The halfway point is (f₁+f₂)/2 = 2¹²⁸ - 2¹⁰³. // // The same is true of float64, with different constants: s/24/53/ and s/128/1024/.