math: special cases for Modf, Frexp and Ldexp; added Modf_386
Also moved Modf from bits.go into modf.go and added timing tests.
R=rsc
CC=golang-dev
https://golang.org/cl/202042
diff --git a/src/pkg/math/Makefile b/src/pkg/math/Makefile
index f228084..0e89df7 100644
--- a/src/pkg/math/Makefile
+++ b/src/pkg/math/Makefile
@@ -18,6 +18,7 @@
fmod_386.$O\
hypot_386.$O\
log_386.$O\
+ modf_386.$O\
sin_386.$O\
sqrt_386.$O\
tan_386.$O\
@@ -44,6 +45,7 @@
hypot.go\
log.go\
log1p.go\
+ modf.go\
pow.go\
pow10.go\
sin.go\
diff --git a/src/pkg/math/all_test.go b/src/pkg/math/all_test.go
index fa9c4bd..c0ac152 100644
--- a/src/pkg/math/all_test.go
+++ b/src/pkg/math/all_test.go
@@ -1,4 +1,4 @@
-// Copyright 2009-2010 The Go Authors. All rights reserved.
+// 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.
@@ -220,6 +220,25 @@
8.734595415957246977711748e-01,
1.314075231424398637614104e+00,
}
+
+type fi struct {
+ f float64
+ i int
+}
+
+var frexp = []fi{
+ fi{6.2237649061045918750e-01, 3},
+ fi{9.6735905932226306250e-01, 3},
+ fi{-5.5376011438400318000e-01, -1},
+ fi{-6.2632545228388436250e-01, 3},
+ fi{6.02268356699901081250e-01, 4},
+ fi{7.3159430981099115000e-01, 2},
+ fi{6.5363542893241332500e-01, 3},
+ fi{6.8198497760900255000e-01, 2},
+ fi{9.1265404584042750000e-01, 1},
+ fi{-5.4287029803597508250e-01, 4},
+}
+
var log = []float64{
1.605231462693062999102599e+00,
2.0462560018708770653153909e+00,
@@ -256,6 +275,18 @@
1.8088493239630770262045333e-02,
-9.0865245631588989681559268e-02,
}
+var modf = [][2]float64{
+ [2]float64{4.0000000000000000e+00, 9.7901192488367350108546816e-01},
+ [2]float64{7.0000000000000000e+00, 7.3887247457810456552351752e-01},
+ [2]float64{0.0000000000000000e+00, -2.7688005719200159404635997e-01},
+ [2]float64{-5.0000000000000000e+00, -1.060361827107492160848778e-02},
+ [2]float64{9.0000000000000000e+00, 6.3629370719841737980004837e-01},
+ [2]float64{2.0000000000000000e+00, 9.2637723924396464525443662e-01},
+ [2]float64{5.0000000000000000e+00, 2.2908343145930665230025625e-01},
+ [2]float64{2.0000000000000000e+00, 7.2793991043601025126008608e-01},
+ [2]float64{1.0000000000000000e+00, 8.2530809168085506044576505e-01},
+ [2]float64{-8.0000000000000000e+00, -6.8592476857560136238589621e-01},
+}
var pow = []float64{
9.5282232631648411840742957e+04,
5.4811599352999901232411871e+07,
@@ -516,6 +547,19 @@
NaN(),
}
+var vffrexpSC = []float64{
+ Inf(-1),
+ 0,
+ Inf(1),
+ NaN(),
+}
+var frexpSC = []fi{
+ fi{Inf(-1), 0},
+ fi{0, 0},
+ fi{Inf(1), 0},
+ fi{NaN(), 0},
+}
+
var vfhypotSC = [][2]float64{
[2]float64{Inf(-1), Inf(-1)},
[2]float64{Inf(-1), 0},
@@ -581,6 +625,17 @@
NaN(),
}
+var vfmodfSC = []float64{
+ Inf(-1),
+ Inf(1),
+ NaN(),
+}
+var modfSC = [][2]float64{
+ [2]float64{Inf(-1), NaN()},
+ [2]float64{Inf(1), NaN()},
+ [2]float64{NaN(), NaN()},
+}
+
var vfpowSC = [][2]float64{
[2]float64{-Pi, Pi},
[2]float64{-Pi, -Pi},
@@ -919,6 +974,19 @@
}
}
+func TestFrexp(t *testing.T) {
+ for i := 0; i < len(vf); i++ {
+ if f, j := Frexp(vf[i]); !veryclose(frexp[i].f, f) || frexp[i].i != j {
+ t.Errorf("Frexp(%g) = %g, %d, want %g, %d\n", vf[i], f, j, frexp[i].f, frexp[i].i)
+ }
+ }
+ for i := 0; i < len(vffrexpSC); i++ {
+ if f, j := Frexp(vffrexpSC[i]); !alike(frexpSC[i].f, f) || frexpSC[i].i != j {
+ t.Errorf("Frexp(%g) = %g, %d, want %g, %d\n", vffrexpSC[i], f, j, frexpSC[i].f, frexpSC[i].i)
+ }
+ }
+}
+
func TestHypot(t *testing.T) {
for i := 0; i < len(vf); i++ {
a := Fabs(1e200 * tanh[i] * Sqrt(2))
@@ -933,6 +1001,19 @@
}
}
+func TestLdexp(t *testing.T) {
+ for i := 0; i < len(vf); i++ {
+ if f := Ldexp(frexp[i].f, frexp[i].i); !veryclose(vf[i], f) {
+ t.Errorf("Ldexp(%g, %d) = %g, want %g\n", frexp[i].f, frexp[i].i, f, vf[i])
+ }
+ }
+ for i := 0; i < len(vffrexpSC); i++ {
+ if f := Ldexp(frexpSC[i].f, frexpSC[i].i); !alike(vffrexpSC[i], f) {
+ t.Errorf("Ldexp(%g, %d) = %g, want %g\n", frexpSC[i].f, frexpSC[i].i, f, vffrexpSC[i])
+ }
+ }
+}
+
func TestLog(t *testing.T) {
for i := 0; i < len(vf); i++ {
a := Fabs(vf[i])
@@ -985,6 +1066,19 @@
}
}
+func TestModf(t *testing.T) {
+ for i := 0; i < len(vf); i++ {
+ if f, g := Modf(vf[i]); !veryclose(modf[i][0], f) || !veryclose(modf[i][1], g) {
+ t.Errorf("Modf(%g) = %g, %g, want %g, %g\n", vf[i], f, g, modf[i][0], modf[i][1])
+ }
+ }
+ for i := 0; i < len(vfmodfSC); i++ {
+ if f, g := Modf(vfmodfSC[i]); !alike(modfSC[i][0], f) || !alike(modfSC[i][1], g) {
+ t.Errorf("Modf(%g) = %g, %g, want %g, %g\n", vfmodfSC[i], f, g, modfSC[i][0], modfSC[i][1])
+ }
+ }
+}
+
func TestPow(t *testing.T) {
for i := 0; i < len(vf); i++ {
if f := Pow(10, vf[i]); !close(pow[i], f) {
@@ -1220,12 +1314,24 @@
}
}
+func BenchmarkFrexp(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ Frexp(8)
+ }
+}
+
func BenchmarkHypot(b *testing.B) {
for i := 0; i < b.N; i++ {
Hypot(3, 4)
}
}
+func BenchmarkLdexp(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ Ldexp(.5, 2)
+ }
+}
+
func BenchmarkLog(b *testing.B) {
for i := 0; i < b.N; i++ {
Log(.5)
@@ -1244,6 +1350,12 @@
}
}
+func BenchmarkModf(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ Modf(1.5)
+ }
+}
+
func BenchmarkPowInt(b *testing.B) {
for i := 0; i < b.N; i++ {
Pow(2, 2)
diff --git a/src/pkg/math/bits.go b/src/pkg/math/bits.go
index 9f93a19..ccbcf06 100644
--- a/src/pkg/math/bits.go
+++ b/src/pkg/math/bits.go
@@ -53,7 +53,14 @@
// It returns frac and exp satisfying f == frac × 2<sup>exp</sup>,
// with the absolute value of frac in the interval [½, 1).
func Frexp(f float64) (frac float64, exp int) {
- if f == 0 {
+ // TODO(rsc): Remove manual inlining of IsNaN, IsInf
+ // when compiler does it for us
+ // special cases
+ switch {
+ case f == 0:
+ return
+ case f < -MaxFloat64 || f > MaxFloat64 || f != f: // IsInf(f, 0) || IsNaN(f):
+ frac = f
return
}
x := Float64bits(f)
@@ -67,6 +74,12 @@
// Ldexp is the inverse of Frexp.
// It returns frac × 2<sup>exp</sup>.
func Ldexp(frac float64, exp int) float64 {
+ // TODO(rsc): Remove manual inlining of IsNaN, IsInf
+ // when compiler does it for us
+ // special cases
+ if frac != frac { // IsNaN(frac)
+ return NaN()
+ }
x := Float64bits(frac)
exp += int(x>>shift) & mask
if exp <= 0 {
@@ -82,27 +95,3 @@
x |= uint64(exp) << shift
return Float64frombits(x)
}
-
-// 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) (int float64, frac float64) {
- if f < 1 {
- if f < 0 {
- int, frac = Modf(-f)
- return -int, -frac
- }
- return 0, f
- }
-
- x := Float64bits(f)
- e := uint(x>>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/modf.go b/src/pkg/math/modf.go
new file mode 100644
index 0000000..ae0c7c8
--- /dev/null
+++ b/src/pkg/math/modf.go
@@ -0,0 +1,33 @@
+// 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
+
+// Modf returns integer and fractional floating-point numbers
+// that sum to f. Both values have the same sign as f.
+//
+// Special cases are:
+// Modf(+Inf) = +Inf, NaN
+// Modf(-Inf) = -Inf, NaN
+// Modf(NaN) = NaN, NaN
+func Modf(f float64) (int float64, frac float64) {
+ if f < 1 {
+ if f < 0 {
+ int, frac = Modf(-f)
+ return -int, -frac
+ }
+ return 0, f
+ }
+
+ x := Float64bits(f)
+ e := uint(x>>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/modf_386.s b/src/pkg/math/modf_386.s
new file mode 100644
index 0000000..5ccab98
--- /dev/null
+++ b/src/pkg/math/modf_386.s
@@ -0,0 +1,19 @@
+// Copyright 2010 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.
+
+// func Modf(x float64) (int float64, frac float64)
+TEXT ·Modf(SB),7,$0
+ FMOVD x+0(FP), F0 // F0=x
+ FMOVD F0, F1 // F0=x, F1=x
+ FSTCW -2(SP) // save old Control Word
+ MOVW -2(SP), AX
+ ORW $0x0c00, AX // Rounding Control set to truncate
+ MOVW AX, -4(SP) // store new Control Word
+ FLDCW -4(SP) // load new Control Word
+ FRNDINT // F0=trunc(x), F1=x
+ FLDCW -2(SP) // load old Control Word
+ FSUBD F0, F1 // F0=trunc(x), F1=x-trunc(x)
+ FMOVDP F0, i+8(FP) // F0=x-trunc(x)
+ FMOVDP F0, f+16(FP)
+ RET
diff --git a/src/pkg/math/modf_decl.go b/src/pkg/math/modf_decl.go
new file mode 100644
index 0000000..7add2af
--- /dev/null
+++ b/src/pkg/math/modf_decl.go
@@ -0,0 +1,7 @@
+// Copyright 2010 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
+
+func Modf(f float64) (int float64, frac float64)
