51 lines
1.7 KiB
C
51 lines
1.7 KiB
C
// fenv.h — floating-point environment.
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//
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// The W65816 softFloat / softDouble runtime is fixed at round-to-
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// nearest-even (FE_TONEAREST). Other rounding modes can be set/queried
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// but they have no effect on softFloat output — softDouble always uses
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// RNE. Exception flags are tracked as a static word but never raised
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// by the soft-float libraries (they don't model overflow/underflow/
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// inexact at the IEEE level; overflow → infinity, underflow → zero,
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// inexact silently rounded).
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//
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// All functions return 0 on success (per C99 7.6.3.1).
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//
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// This header exists so portable code that includes <fenv.h> and calls
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// fegetround() / fesetround() compiles cleanly — it just won't observe
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// non-default rounding.
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#ifndef _FENV_H
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#define _FENV_H
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typedef unsigned short fenv_t;
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typedef unsigned short fexcept_t;
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// Rounding modes. Only FE_TONEAREST has effect on this target.
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#define FE_TONEAREST 0
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#define FE_DOWNWARD 1
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#define FE_UPWARD 2
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#define FE_TOWARDZERO 3
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// Exception flags. Never raised by softFloat/softDouble.
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#define FE_INVALID 0x01
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#define FE_DIVBYZERO 0x02
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#define FE_OVERFLOW 0x04
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#define FE_UNDERFLOW 0x08
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#define FE_INEXACT 0x10
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#define FE_ALL_EXCEPT (FE_INVALID|FE_DIVBYZERO|FE_OVERFLOW|FE_UNDERFLOW|FE_INEXACT)
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#define FE_DFL_ENV ((const fenv_t *)0)
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int feclearexcept(int excepts);
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int fegetexceptflag(fexcept_t *flagp, int excepts);
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int feraiseexcept(int excepts);
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int fesetexceptflag(const fexcept_t *flagp, int excepts);
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int fetestexcept(int excepts);
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int fegetround(void);
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int fesetround(int round);
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int fegetenv(fenv_t *envp);
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int feholdexcept(fenv_t *envp);
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int fesetenv(const fenv_t *envp);
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int feupdateenv(const fenv_t *envp);
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#endif
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