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89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
/* go-matherr.c -- a Go version of the matherr function.
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Copyright 2012 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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/* The gccgo version of the math library calls libc functions. On
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some systems, such as Solaris, those functions will call matherr on
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exceptional conditions. This is a version of matherr appropriate
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for Go, one which returns the values that the Go math library
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expects. This is fine for pure Go programs. For mixed Go and C
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programs this will be problematic if the C programs themselves use
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matherr. Normally the C version of matherr will override this, and
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the Go code will just have to cope. If this turns out to be too
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problematic we can change to run pure Go code in the math library
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on systems that use matherr. */
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#include <math.h>
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#include <stdint.h>
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#include "config.h"
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#if defined(HAVE_MATHERR) && defined(HAVE_STRUCT_EXCEPTION)
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#define PI 3.14159265358979323846264338327950288419716939937510582097494459
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int
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matherr (struct exception* e)
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{
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const char *n;
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if (e->type != DOMAIN)
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return 0;
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n = e->name;
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if (__builtin_strcmp (n, "acos") == 0
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|| __builtin_strcmp (n, "asin") == 0)
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e->retval = __builtin_nan ("");
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else if (__builtin_strcmp (n, "atan2") == 0)
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{
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if (e->arg1 == 0 && e->arg2 == 0)
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{
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double nz;
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nz = -0.0;
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if (__builtin_memcmp (&e->arg2, &nz, sizeof (double)) != 0)
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e->retval = e->arg1;
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else
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e->retval = copysign (PI, e->arg1);
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}
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else
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return 0;
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}
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else if (__builtin_strcmp (n, "log") == 0
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|| __builtin_strcmp (n, "log10") == 0)
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e->retval = __builtin_nan ("");
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else if (__builtin_strcmp (n, "pow") == 0)
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{
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if (e->arg1 < 0)
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e->retval = __builtin_nan ("");
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else if (e->arg1 == 0 && e->arg2 == 0)
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e->retval = 1.0;
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else if (e->arg1 == 0 && e->arg2 < 0)
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{
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double i;
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if (modf (e->arg2, &i) == 0 && ((int64_t) i & 1) == 1)
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e->retval = copysign (__builtin_inf (), e->arg1);
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else
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e->retval = __builtin_inf ();
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}
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else
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return 0;
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}
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else if (__builtin_strcmp (n, "sqrt") == 0)
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{
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if (e->arg1 < 0)
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e->retval = __builtin_nan ("");
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else
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return 0;
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}
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else
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return 0;
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return 1;
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}
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#endif
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