From: Russ Cox Date: Fri, 16 Oct 2009 06:09:22 +0000 (-0700) Subject: move math out of runtime. X-Git-Tag: weekly.2009-11-06~280 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=488ca3c7a67ecb1ce4068ab40da6003feac5e16c;p=gostls13.git move math out of runtime. a step toward enforcing package boundaries, necessary to eliminate global package name space. R=r DELTA=581 (310 added, 271 deleted, 0 changed) OCL=35805 CL=35823 --- diff --git a/src/pkg/math/Makefile b/src/pkg/math/Makefile index bf8d99a608..74072503cf 100644 --- a/src/pkg/math/Makefile +++ b/src/pkg/math/Makefile @@ -16,6 +16,7 @@ ALLGOFILES=\ asin.go\ atan.go\ atan2.go\ + bits.go\ const.go\ exp.go\ fabs.go\ @@ -25,12 +26,12 @@ ALLGOFILES=\ log.go\ pow.go\ pow10.go\ - runtime.go\ sin.go\ sinh.go\ sqrt.go\ tan.go\ tanh.go\ + unsafe.go\ NOGOFILES=\ $(subst _$(GOARCH).$O,.go,$(OFILES_$(GOARCH))) diff --git a/src/pkg/math/bits.go b/src/pkg/math/bits.go new file mode 100644 index 0000000000..00071aa0a7 --- /dev/null +++ b/src/pkg/math/bits.go @@ -0,0 +1,105 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package math + +const ( + uvnan = 0x7FF0000000000001; + uvinf = 0x7FF0000000000000; + uvneginf = 0xFFF0000000000000; + mask = 0x7FF; + shift = 64 - 11 - 1; + bias = 1022; +) + +// Inf returns positive infinity if sign >= 0, negative infinity if sign < 0. +func Inf(sign int) float64 { + var v uint64; + if sign >= 0 { + v = uvinf; + } else { + v = uvneginf; + } + return Float64frombits(v); +} + +// NaN returns an IEEE 754 ``not-a-number'' value. +func NaN() float64 { + return Float64frombits(uvnan); +} + +// IsNaN returns whether f is an IEEE 754 ``not-a-number'' value. +func IsNaN(f float64) (is bool) { + x := Float64bits(f); + return uint32(x>>shift) & mask == mask && x != uvinf && x != uvneginf; +} + +// IsInf returns whether f is an infinity, according to sign. +// If sign > 0, IsInf returns whether f is positive infinity. +// If sign < 0, IsInf returns whether f is negative infinity. +// If sign == 0, IsInf returns whether f is either infinity. +func IsInf(f float64, sign int) bool { + x := Float64bits(f); + return sign >= 0 && x == uvinf || sign <= 0 && x == uvneginf; +} + +// Frexp breaks f into a normalized fraction +// and an integral power of two. +// It returns frac and exp satisfying f == frac × 2exp, +// with the absolute value of frac in the interval [½, 1). +func Frexp(f float64) (frac float64, exp int) { + if f == 0 { + return; + } + x := Float64bits(f); + exp = int((x>>shift)&mask) - bias; + x &^= mask<exp. +func Ldexp(frac float64, exp int) float64 { + x := Float64bits(frac); + exp += int(x>>shift) & mask; + if exp <= 0 { + return 0; // underflow + } + if exp >= mask { // overflow + if frac < 0 { + return Inf(-1); + } + return Inf(1); + } + x &^= mask<>shift)&mask - bias; + + // Keep the top 11+e bits, the integer part; clear the rest. + if e < 64-11 { + x &^= 1<<(64-11-e) - 1; + } + int = Float64frombits(x); + frac = f - int; + return; +} + diff --git a/src/pkg/math/runtime.go b/src/pkg/math/runtime.go deleted file mode 100644 index 69d333825b..0000000000 --- a/src/pkg/math/runtime.go +++ /dev/null @@ -1,52 +0,0 @@ -// Copyright 2009 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package math - -// implemented in C, in ../../runtime -// perhaps one day the implementations will move here. - -// Float32bits returns the IEEE 754 binary representation of f. -func Float32bits(f float32) (b uint32) - -// Float32frombits returns the floating point number corresponding -// to the IEEE 754 binary representation b. -func Float32frombits(b uint32) (f float32) - -// Float64bits returns the IEEE 754 binary representation of f. -func Float64bits(f float64) (b uint64) - -// Float64frombits returns the floating point number corresponding -// the IEEE 754 binary representation b. -func Float64frombits(b uint64) (f float64) - -// Frexp breaks f into a normalized fraction -// and an integral power of two. -// It returns frac and exp satisfying f == frac × 2exp, -// with the absolute value of frac in the interval [½, 1). -func Frexp(f float64) (frac float64, exp int) - -// Inf returns positive infinity if sign >= 0, negative infinity if sign < 0. -func Inf(sign int32) (f float64) - -// IsInf returns whether f is an infinity, according to sign. -// If sign > 0, IsInf returns whether f is positive infinity. -// If sign < 0, IsInf returns whether f is negative infinity. -// If sign == 0, IsInf returns whether f is either infinity. -func IsInf(f float64, sign int) (is bool) - -// IsNaN returns whether f is an IEEE 754 ``not-a-number'' value. -func IsNaN(f float64) (is bool) - -// Ldexp is the inverse of Frexp. -// It returns frac × 2exp. -func Ldexp(frac float64, exp int) (f float64) - -// Modf returns integer and fractional floating-point numbers -// that sum to f. -// Integer and frac have the same sign as f. -func Modf(f float64) (integer float64, frac float64) - -// NaN returns an IEEE 754 ``not-a-number'' value. -func NaN() (f float64) diff --git a/src/pkg/math/unsafe.go b/src/pkg/math/unsafe.go new file mode 100644 index 0000000000..cfc64634e1 --- /dev/null +++ b/src/pkg/math/unsafe.go @@ -0,0 +1,30 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package math + +import "unsafe" + +// Float32bits returns the IEEE 754 binary representation of f. +func Float32bits(f float32) uint32 { + return *(*uint32)(unsafe.Pointer(&f)); +} + +// Float32frombits returns the floating point number corresponding +// to the IEEE 754 binary representation b. +func Float32frombits(b uint32) float32 { + return *(*float32)(unsafe.Pointer(&b)); +} + +// Float64bits returns the IEEE 754 binary representation of f. +func Float64bits(f float64) uint64 { + return *(*uint64)(unsafe.Pointer(&f)); +} + +// Float64frombits returns the floating point number corresponding +// the IEEE 754 binary representation b. +func Float64frombits(b uint64) float64 { + return *(*float64)(unsafe.Pointer(&b)); +} + diff --git a/src/pkg/runtime/float.cgo b/src/pkg/runtime/float.c similarity index 78% rename from src/pkg/runtime/float.cgo rename to src/pkg/runtime/float.c index 38114aa854..5122f359a7 100644 --- a/src/pkg/runtime/float.cgo +++ b/src/pkg/runtime/float.c @@ -2,7 +2,6 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -package math #include "runtime.h" static uint64 uvnan = 0x7FF0000000000001ULL; @@ -172,47 +171,3 @@ modf(float64 d, float64 *ip) return d - dd; } -func Frexp(f float64) (frac float64, exp int32) { - frac = frexp(f, &exp); -} - -func Ldexp(frac float64, exp int32) (f float64) { - f = ldexp(frac, exp); -} - -func Modf(f float64) (integer float64, frac float64) { - frac = modf(f, &integer); -} - -func IsInf(f float64, sign int32) (is bool) { - is = isInf(f, sign); -} - -func IsNaN(f float64) (is bool) { - is = isNaN(f); -} - -func Inf(sign int32) (f float64) { - f = Inf(sign); -} - -func NaN() (f float64) { - f = NaN(); -} - -func Float32bits(f float32) (b uint32) { - b = float32tobits(f); -} - -func Float64bits(f float64) (b uint64) { - b = float64tobits(f); -} - -func Float32frombits(b uint32) (f float32) { - f = float32frombits(b); -} - -func Float64frombits(b uint64) (f float64) { - f = float64frombits(b); -} -