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complex divide: match C99 implementation
R=iant, ken2, r, r2, ken3 CC=golang-dev https://golang.org/cl/1686044
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@ -4,33 +4,57 @@
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#include "runtime.h"
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// complex128div(num, den complex128) (quo complex128)
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typedef struct Complex128 Complex128;
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void
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·complex128div(float64 numreal, float64 numimag,
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float64 denreal, float64 denimag,
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float64 quoreal, float64 quoimag)
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·complex128div(Complex128 n, Complex128 d, Complex128 q)
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{
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int32 ninf, dinf, nnan, dnan;
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float64 a, b, ratio, denom;
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a = denreal;
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if(a < 0)
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a = -a;
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b = denimag;
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if(b < 0)
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b = -b;
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if(a <= b) {
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if(b == 0)
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panicstring("complex divide by zero");
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ratio = denreal/denimag;
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denom = denreal*ratio + denimag;
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quoreal = (numreal*ratio + numimag) / denom;
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quoimag = (numimag*ratio - numreal) / denom;
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// Special cases as in C99.
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ninf = isInf(n.real, 0) || isInf(n.imag, 0);
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dinf = isInf(d.real, 0) || isInf(d.imag, 0);
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nnan = !ninf && (isNaN(n.real) || isNaN(n.imag));
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dnan = !dinf && (isNaN(d.real) || isNaN(d.imag));
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if(nnan || dnan) {
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q.real = NaN();
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q.imag = NaN();
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} else if(ninf && !dinf && !dnan) {
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q.real = Inf(0);
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q.imag = Inf(0);
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} else if(!ninf && !nnan && dinf) {
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q.real = 0;
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q.imag = 0;
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} else if(d.real == 0 && d.imag == 0) {
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if(n.real == 0 && n.imag == 0) {
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q.real = NaN();
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q.imag = NaN();
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} else {
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q.real = Inf(0);
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q.imag = Inf(0);
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}
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} else {
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ratio = denimag/denreal;
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denom = denimag*ratio + denreal;
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quoreal = (numimag*ratio + numreal) / denom;
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quoimag = (numimag - numreal*ratio) / denom;
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// Standard complex arithmetic, factored to avoid unnecessary overflow.
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a = d.real;
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if(a < 0)
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a = -a;
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b = d.imag;
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if(b < 0)
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b = -b;
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if(a <= b) {
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ratio = d.real/d.imag;
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denom = d.real*ratio + d.imag;
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q.real = (n.real*ratio + n.imag) / denom;
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q.imag = (n.imag*ratio - n.real) / denom;
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} else {
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ratio = d.imag/d.real;
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denom = d.imag*ratio + d.real;
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q.real = (n.imag*ratio + n.real) / denom;
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q.imag = (n.imag - n.real*ratio) / denom;
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}
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}
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FLUSH(&quoreal);
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FLUSH(&quoimag);
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FLUSH(&q);
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}
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61
test/cmplxdivide.c
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61
test/cmplxdivide.c
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@ -0,0 +1,61 @@
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// gcc '-std=c99' cmplxdivide.c && a.out >cmplxdivide1.go
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#include <complex.h>
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#include <math.h>
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#include <stdio.h>
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#include <string.h>
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#define nelem(x) (sizeof(x)/sizeof((x)[0]))
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double f[] = {
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0,
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1,
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-1,
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2,
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NAN,
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INFINITY,
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-INFINITY,
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};
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char*
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fmt(double g)
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{
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static char buf[10][30];
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static int n;
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char *p;
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p = buf[n++];
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if(n == 10)
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n = 0;
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sprintf(p, "%g", g);
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if(strcmp(p, "-0") == 0)
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strcpy(p, "negzero");
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return p;
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}
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int
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main(void)
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{
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int i, j, k, l;
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double complex n, d, q;
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printf("// # generated by cmplxdivide.c\n");
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printf("\n");
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printf("package main\n");
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printf("var tests = []Test{\n");
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for(i=0; i<nelem(f); i++)
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for(j=0; j<nelem(f); j++)
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for(k=0; k<nelem(f); k++)
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for(l=0; l<nelem(f); l++) {
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n = f[i] + f[j]*I;
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d = f[k] + f[l]*I;
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q = n/d;
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printf("\tTest{cmplx(%s, %s), cmplx(%s, %s), cmplx(%s, %s)},\n", fmt(creal(n)), fmt(cimag(n)), fmt(creal(d)), fmt(cimag(d)), fmt(creal(q)), fmt(cimag(q)));
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}
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printf("}\n");
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return 0;
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}
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43
test/cmplxdivide.go
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43
test/cmplxdivide.go
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@ -0,0 +1,43 @@
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// $G $D/$F.go $D/cmplxdivide1.go && $L $D/$F.$A && ./$A.out
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Driver for complex division table defined in cmplxdivide1.go
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package main
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import (
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"cmath"
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"fmt"
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"math"
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)
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type Test struct{
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f, g complex128
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out complex128
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}
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var nan = math.NaN()
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var inf = math.Inf(1)
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var negzero = math.Copysign(0, -1)
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func calike(a, b complex128) bool {
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switch {
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case cmath.IsInf(a) && cmath.IsInf(b):
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return true
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case cmath.IsNaN(a) && cmath.IsNaN(b):
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return true
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}
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return a == b
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}
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func main() {
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for _, t := range tests {
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x := t.f/t.g
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if !calike(x, t.out) {
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fmt.Printf("%v/%v: expected %v error; got %v\n", t.f, t.g, t.out, x)
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}
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}
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}
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2406
test/cmplxdivide1.go
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2406
test/cmplxdivide1.go
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File diff suppressed because it is too large
Load Diff
@ -53,14 +53,6 @@ FAIL
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=========== ./turing.go
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Hello World!
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=========== ./zerodivide.go
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complex 0/0: expected no error; got "runtime error: complex divide by zero"
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complex64 0/0: expected no error; got "runtime error: complex divide by zero"
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complex128 0/0: expected no error; got "runtime error: complex divide by zero"
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complex 1/0: expected no error; got "runtime error: complex divide by zero"
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complex64 1/0: expected no error; got "runtime error: complex divide by zero"
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complex128 1/0: expected no error; got "runtime error: complex divide by zero"
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== ken/
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=========== ken/cplx0.go
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}
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func test7() {
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if syscall.ARCH == "arm" {
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// ARM doesn't have floating point yet
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if syscall.ARCH == "arm" || syscall.OS == "nacl" {
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// ARM doesn't have integer divide trap yet
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return
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}
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defer mustRecover("complex divide by zero")
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var x, y complex
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defer mustRecover("divide by zero")
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var x, y int
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println(x / y)
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}
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@ -114,16 +114,15 @@ func error(fn func()) (error string) {
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}
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type FloatTest struct{
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name string
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f, g float64
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out float64
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}
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var floatTests = []FloatTest{
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FloatTest{"float64 0/0", 0, 0, nan },
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FloatTest{"float64 nan/0", nan, 0, nan },
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FloatTest{"float64 inf/0", inf, 0, inf },
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FloatTest{"float64 -inf/0", negInf, 0, negInf },
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FloatTest{0, 0, nan},
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FloatTest{nan, 0, nan},
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FloatTest{inf, 0, inf},
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FloatTest{negInf, 0, negInf},
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}
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func alike(a, b float64) bool {
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@ -138,6 +137,9 @@ func alike(a, b float64) bool {
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func main() {
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for _, t := range errorTests {
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if t.err != "" && syscall.OS == "nacl" {
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continue
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}
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err := error(t.fn)
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switch {
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case t.err == "" && err == "":
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@ -158,7 +160,7 @@ func main() {
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for _, t := range floatTests {
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x := t.f/t.g
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if !alike(x, t.out) {
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fmt.Printf("%s: expected %g error; got %g\n", t.name, t.out, x)
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fmt.Printf("%v/%v: expected %g error; got %g\n", t.f, t.g, t.out, x)
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}
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}
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}
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