Implement flush-to-zero mode (denormal results are replaced with zero).

[qemu.git] / fpu / softfloat.h

/*============================================================================

This C header file is part of the SoftFloat IEC/IEEE Floating-point Arithmetic
Package, Release 2b.

Written by John R. Hauser.  This work was made possible in part by the
International Computer Science Institute, located at Suite 600, 1947 Center
Street, Berkeley, California 94704.  Funding was partially provided by the
National Science Foundation under grant MIP-9311980.  The original version
of this code was written as part of a project to build a fixed-point vector
processor in collaboration with the University of California at Berkeley,
overseen by Profs. Nelson Morgan and John Wawrzynek.  More information
is available through the Web page `http://www.cs.berkeley.edu/~jhauser/
arithmetic/SoftFloat.html'.

THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort has
been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT TIMES
RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO PERSONS
AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ALL LOSSES,
COSTS, OR OTHER PROBLEMS THEY INCUR DUE TO THE SOFTWARE, AND WHO FURTHERMORE
EFFECTIVELY INDEMNIFY JOHN HAUSER AND THE INTERNATIONAL COMPUTER SCIENCE
INSTITUTE (possibly via similar legal warning) AGAINST ALL LOSSES, COSTS, OR
OTHER PROBLEMS INCURRED BY THEIR CUSTOMERS AND CLIENTS DUE TO THE SOFTWARE.

Derivative works are acceptable, even for commercial purposes, so long as
(1) the source code for the derivative work includes prominent notice that
the work is derivative, and (2) the source code includes prominent notice with
these four paragraphs for those parts of this code that are retained.

=============================================================================*/

#ifndef SOFTFLOAT_H
#define SOFTFLOAT_H

#if defined(HOST_SOLARIS) && defined(NEEDS_LIBSUNMATH)
#include <sunmath.h>
#endif

#include <inttypes.h>
#include "config.h"

/*----------------------------------------------------------------------------
| Each of the following `typedef's defines the most convenient type that holds
| integers of at least as many bits as specified.  For example, `uint8' should
| be the most convenient type that can hold unsigned integers of as many as
| 8 bits.  The `flag' type must be able to hold either a 0 or 1.  For most
| implementations of C, `flag', `uint8', and `int8' should all be `typedef'ed
| to the same as `int'.
*----------------------------------------------------------------------------*/
typedef uint8_t flag;
typedef uint8_t uint8;
typedef int8_t int8;
#ifndef _AIX
typedef int uint16;
typedef int int16;
#endif
typedef unsigned int uint32;
typedef signed int int32;
typedef uint64_t uint64;
typedef int64_t int64;

/*----------------------------------------------------------------------------
| Each of the following `typedef's defines a type that holds integers
| of _exactly_ the number of bits specified.  For instance, for most
| implementation of C, `bits16' and `sbits16' should be `typedef'ed to
| `unsigned short int' and `signed short int' (or `short int'), respectively.
*----------------------------------------------------------------------------*/
typedef uint8_t bits8;
typedef int8_t sbits8;
typedef uint16_t bits16;
typedef int16_t sbits16;
typedef uint32_t bits32;
typedef int32_t sbits32;
typedef uint64_t bits64;
typedef int64_t sbits64;

#define LIT64( a ) a##LL
#define INLINE static inline

/*----------------------------------------------------------------------------
| The macro `FLOATX80' must be defined to enable the extended double-precision
| floating-point format `floatx80'.  If this macro is not defined, the
| `floatx80' type will not be defined, and none of the functions that either
| input or output the `floatx80' type will be defined.  The same applies to
| the `FLOAT128' macro and the quadruple-precision format `float128'.
*----------------------------------------------------------------------------*/
#ifdef CONFIG_SOFTFLOAT
/* bit exact soft float support */
#define FLOATX80
#define FLOAT128
#else
/* native float support */
#if (defined(__i386__) || defined(__x86_64__)) && !defined(_BSD)
#define FLOATX80
#endif
#endif /* !CONFIG_SOFTFLOAT */

#define STATUS_PARAM , float_status *status
#define STATUS(field) status->field
#define STATUS_VAR , status

/*----------------------------------------------------------------------------
| Software IEC/IEEE floating-point ordering relations
*----------------------------------------------------------------------------*/
enum {
    float_relation_less      = -1,
    float_relation_equal     =  0,
    float_relation_greater   =  1,
    float_relation_unordered =  2
};

#ifdef CONFIG_SOFTFLOAT
/*----------------------------------------------------------------------------
| Software IEC/IEEE floating-point types.
*----------------------------------------------------------------------------*/
/* Use structures for soft-float types.  This prevents accidentally mixing
   them with native int/float types.  A sufficiently clever compiler and
   sane ABI should be able to see though these structs.  However
   x86/gcc 3.x seems to struggle a bit, so leave them disabled by default.  */
//#define USE_SOFTFLOAT_STRUCT_TYPES
#ifdef USE_SOFTFLOAT_STRUCT_TYPES
typedef struct {
    uint32_t v;
} float32;
/* The cast ensures an error if the wrong type is passed.  */
#define float32_val(x) (((float32)(x)).v)
#define make_float32(x) __extension__ ({ float32 f32_val = {x}; f32_val; })
typedef struct {
    uint64_t v;
} float64;
#define float64_val(x) (((float64)(x)).v)
#define make_float64(x) __extension__ ({ float64 f64_val = {x}; f64_val; })
#else
typedef uint32_t float32;
typedef uint64_t float64;
#define float32_val(x) (x)
#define float64_val(x) (x)
#define make_float32(x) (x)
#define make_float64(x) (x)
#endif
#ifdef FLOATX80
typedef struct {
    uint64_t low;
    uint16_t high;
} floatx80;
#endif
#ifdef FLOAT128
typedef struct {
#ifdef WORDS_BIGENDIAN
    uint64_t high, low;
#else
    uint64_t low, high;
#endif
} float128;
#endif

/*----------------------------------------------------------------------------
| Software IEC/IEEE floating-point underflow tininess-detection mode.
*----------------------------------------------------------------------------*/
enum {
    float_tininess_after_rounding  = 0,
    float_tininess_before_rounding = 1
};

/*----------------------------------------------------------------------------
| Software IEC/IEEE floating-point rounding mode.
*----------------------------------------------------------------------------*/
enum {
    float_round_nearest_even = 0,
    float_round_down         = 1,
    float_round_up           = 2,
    float_round_to_zero      = 3
};

/*----------------------------------------------------------------------------
| Software IEC/IEEE floating-point exception flags.
*----------------------------------------------------------------------------*/
enum {
    float_flag_invalid   =  1,
    float_flag_divbyzero =  4,
    float_flag_overflow  =  8,
    float_flag_underflow = 16,
    float_flag_inexact   = 32
};

typedef struct float_status {
    signed char float_detect_tininess;
    signed char float_rounding_mode;
    signed char float_exception_flags;
#ifdef FLOATX80
    signed char floatx80_rounding_precision;
#endif
    flag flush_to_zero;
    flag default_nan_mode;
} float_status;

void set_float_rounding_mode(int val STATUS_PARAM);
void set_float_exception_flags(int val STATUS_PARAM);
INLINE void set_flush_to_zero(flag val STATUS_PARAM)
{
    STATUS(flush_to_zero) = val;
}
INLINE void set_default_nan_mode(flag val STATUS_PARAM)
{
    STATUS(default_nan_mode) = val;
}
INLINE int get_float_exception_flags(float_status *status)
{
    return STATUS(float_exception_flags);
}
#ifdef FLOATX80
void set_floatx80_rounding_precision(int val STATUS_PARAM);
#endif

/*----------------------------------------------------------------------------
| Routine to raise any or all of the software IEC/IEEE floating-point
| exception flags.
*----------------------------------------------------------------------------*/
void float_raise( int8 flags STATUS_PARAM);

/*----------------------------------------------------------------------------
| Software IEC/IEEE integer-to-floating-point conversion routines.
*----------------------------------------------------------------------------*/
float32 int32_to_float32( int STATUS_PARAM );
float64 int32_to_float64( int STATUS_PARAM );
float32 uint32_to_float32( unsigned int STATUS_PARAM );
float64 uint32_to_float64( unsigned int STATUS_PARAM );
#ifdef FLOATX80
floatx80 int32_to_floatx80( int STATUS_PARAM );
#endif
#ifdef FLOAT128
float128 int32_to_float128( int STATUS_PARAM );
#endif
float32 int64_to_float32( int64_t STATUS_PARAM );
float32 uint64_to_float32( uint64_t STATUS_PARAM );
float64 int64_to_float64( int64_t STATUS_PARAM );
float64 uint64_to_float64( uint64_t STATUS_PARAM );
#ifdef FLOATX80
floatx80 int64_to_floatx80( int64_t STATUS_PARAM );
#endif
#ifdef FLOAT128
float128 int64_to_float128( int64_t STATUS_PARAM );
#endif

/*----------------------------------------------------------------------------
| Software IEC/IEEE single-precision conversion routines.
*----------------------------------------------------------------------------*/
int float32_to_int32( float32 STATUS_PARAM );
int float32_to_int32_round_to_zero( float32 STATUS_PARAM );
unsigned int float32_to_uint32( float32 STATUS_PARAM );
unsigned int float32_to_uint32_round_to_zero( float32 STATUS_PARAM );
int64_t float32_to_int64( float32 STATUS_PARAM );
int64_t float32_to_int64_round_to_zero( float32 STATUS_PARAM );
float64 float32_to_float64( float32 STATUS_PARAM );
#ifdef FLOATX80
floatx80 float32_to_floatx80( float32 STATUS_PARAM );
#endif
#ifdef FLOAT128
float128 float32_to_float128( float32 STATUS_PARAM );
#endif

/*----------------------------------------------------------------------------
| Software IEC/IEEE single-precision operations.
*----------------------------------------------------------------------------*/
float32 float32_round_to_int( float32 STATUS_PARAM );
float32 float32_add( float32, float32 STATUS_PARAM );
float32 float32_sub( float32, float32 STATUS_PARAM );
float32 float32_mul( float32, float32 STATUS_PARAM );
float32 float32_div( float32, float32 STATUS_PARAM );
float32 float32_rem( float32, float32 STATUS_PARAM );
float32 float32_sqrt( float32 STATUS_PARAM );
int float32_eq( float32, float32 STATUS_PARAM );
int float32_le( float32, float32 STATUS_PARAM );
int float32_lt( float32, float32 STATUS_PARAM );
int float32_eq_signaling( float32, float32 STATUS_PARAM );
int float32_le_quiet( float32, float32 STATUS_PARAM );
int float32_lt_quiet( float32, float32 STATUS_PARAM );
int float32_compare( float32, float32 STATUS_PARAM );
int float32_compare_quiet( float32, float32 STATUS_PARAM );
int float32_is_nan( float32 );
int float32_is_signaling_nan( float32 );
float32 float32_scalbn( float32, int STATUS_PARAM );

INLINE float32 float32_abs(float32 a)
{
    return make_float32(float32_val(a) & 0x7fffffff);
}

INLINE float32 float32_chs(float32 a)
{
    return make_float32(float32_val(a) ^ 0x80000000);
}

INLINE int float32_is_infinity(float32 a)
{
    return (float32_val(a) & 0x7fffffff) == 0x7f800000;
}

INLINE int float32_is_neg(float32 a)
{
    return float32_val(a) >> 31;
}

INLINE int float32_is_zero(float32 a)
{
    return (float32_val(a) & 0x7fffffff) == 0;
}

#define float32_zero make_float32(0)

/*----------------------------------------------------------------------------
| Software IEC/IEEE double-precision conversion routines.
*----------------------------------------------------------------------------*/
int float64_to_int32( float64 STATUS_PARAM );
int float64_to_int32_round_to_zero( float64 STATUS_PARAM );
unsigned int float64_to_uint32( float64 STATUS_PARAM );
unsigned int float64_to_uint32_round_to_zero( float64 STATUS_PARAM );
int64_t float64_to_int64( float64 STATUS_PARAM );
int64_t float64_to_int64_round_to_zero( float64 STATUS_PARAM );
uint64_t float64_to_uint64 (float64 a STATUS_PARAM);
uint64_t float64_to_uint64_round_to_zero (float64 a STATUS_PARAM);
float32 float64_to_float32( float64 STATUS_PARAM );
#ifdef FLOATX80
floatx80 float64_to_floatx80( float64 STATUS_PARAM );
#endif
#ifdef FLOAT128
float128 float64_to_float128( float64 STATUS_PARAM );
#endif

/*----------------------------------------------------------------------------
| Software IEC/IEEE double-precision operations.
*----------------------------------------------------------------------------*/
float64 float64_round_to_int( float64 STATUS_PARAM );
float64 float64_trunc_to_int( float64 STATUS_PARAM );
float64 float64_add( float64, float64 STATUS_PARAM );
float64 float64_sub( float64, float64 STATUS_PARAM );
float64 float64_mul( float64, float64 STATUS_PARAM );
float64 float64_div( float64, float64 STATUS_PARAM );
float64 float64_rem( float64, float64 STATUS_PARAM );
float64 float64_sqrt( float64 STATUS_PARAM );
int float64_eq( float64, float64 STATUS_PARAM );
int float64_le( float64, float64 STATUS_PARAM );
int float64_lt( float64, float64 STATUS_PARAM );
int float64_eq_signaling( float64, float64 STATUS_PARAM );
int float64_le_quiet( float64, float64 STATUS_PARAM );
int float64_lt_quiet( float64, float64 STATUS_PARAM );
int float64_compare( float64, float64 STATUS_PARAM );
int float64_compare_quiet( float64, float64 STATUS_PARAM );
int float64_is_nan( float64 a );
int float64_is_signaling_nan( float64 );
float64 float64_scalbn( float64, int STATUS_PARAM );

INLINE float64 float64_abs(float64 a)
{
    return make_float64(float64_val(a) & 0x7fffffffffffffffLL);
}

INLINE float64 float64_chs(float64 a)
{
    return make_float64(float64_val(a) ^ 0x8000000000000000LL);
}

INLINE int float64_is_infinity(float64 a)
{
    return (float64_val(a) & 0x7fffffffffffffffLL ) == 0x7ff0000000000000LL;
}

INLINE int float64_is_neg(float64 a)
{
    return float64_val(a) >> 63;
}

INLINE int float64_is_zero(float64 a)
{
    return (float64_val(a) & 0x7fffffffffffffffLL) == 0;
}

#define float64_zero make_float64(0)

#ifdef FLOATX80

/*----------------------------------------------------------------------------
| Software IEC/IEEE extended double-precision conversion routines.
*----------------------------------------------------------------------------*/
int floatx80_to_int32( floatx80 STATUS_PARAM );
int floatx80_to_int32_round_to_zero( floatx80 STATUS_PARAM );
int64_t floatx80_to_int64( floatx80 STATUS_PARAM );
int64_t floatx80_to_int64_round_to_zero( floatx80 STATUS_PARAM );
float32 floatx80_to_float32( floatx80 STATUS_PARAM );
float64 floatx80_to_float64( floatx80 STATUS_PARAM );
#ifdef FLOAT128
float128 floatx80_to_float128( floatx80 STATUS_PARAM );
#endif

/*----------------------------------------------------------------------------
| Software IEC/IEEE extended double-precision operations.
*----------------------------------------------------------------------------*/
floatx80 floatx80_round_to_int( floatx80 STATUS_PARAM );
floatx80 floatx80_add( floatx80, floatx80 STATUS_PARAM );
floatx80 floatx80_sub( floatx80, floatx80 STATUS_PARAM );
floatx80 floatx80_mul( floatx80, floatx80 STATUS_PARAM );
floatx80 floatx80_div( floatx80, floatx80 STATUS_PARAM );
floatx80 floatx80_rem( floatx80, floatx80 STATUS_PARAM );
floatx80 floatx80_sqrt( floatx80 STATUS_PARAM );
int floatx80_eq( floatx80, floatx80 STATUS_PARAM );
int floatx80_le( floatx80, floatx80 STATUS_PARAM );
int floatx80_lt( floatx80, floatx80 STATUS_PARAM );
int floatx80_eq_signaling( floatx80, floatx80 STATUS_PARAM );
int floatx80_le_quiet( floatx80, floatx80 STATUS_PARAM );
int floatx80_lt_quiet( floatx80, floatx80 STATUS_PARAM );
int floatx80_is_nan( floatx80 );
int floatx80_is_signaling_nan( floatx80 );
floatx80 floatx80_scalbn( floatx80, int STATUS_PARAM );

INLINE floatx80 floatx80_abs(floatx80 a)
{
    a.high &= 0x7fff;
    return a;
}

INLINE floatx80 floatx80_chs(floatx80 a)
{
    a.high ^= 0x8000;
    return a;
}

INLINE int floatx80_is_infinity(floatx80 a)
{
    return (a.high & 0x7fff) == 0x7fff && a.low == 0;
}

INLINE int floatx80_is_neg(floatx80 a)
{
    return a.high >> 15;
}

INLINE int floatx80_is_zero(floatx80 a)
{
    return (a.high & 0x7fff) == 0 && a.low == 0;
}

#endif

#ifdef FLOAT128

/*----------------------------------------------------------------------------
| Software IEC/IEEE quadruple-precision conversion routines.
*----------------------------------------------------------------------------*/
int float128_to_int32( float128 STATUS_PARAM );
int float128_to_int32_round_to_zero( float128 STATUS_PARAM );
int64_t float128_to_int64( float128 STATUS_PARAM );
int64_t float128_to_int64_round_to_zero( float128 STATUS_PARAM );
float32 float128_to_float32( float128 STATUS_PARAM );
float64 float128_to_float64( float128 STATUS_PARAM );
#ifdef FLOATX80
floatx80 float128_to_floatx80( float128 STATUS_PARAM );
#endif

/*----------------------------------------------------------------------------
| Software IEC/IEEE quadruple-precision operations.
*----------------------------------------------------------------------------*/
float128 float128_round_to_int( float128 STATUS_PARAM );
float128 float128_add( float128, float128 STATUS_PARAM );
float128 float128_sub( float128, float128 STATUS_PARAM );
float128 float128_mul( float128, float128 STATUS_PARAM );
float128 float128_div( float128, float128 STATUS_PARAM );
float128 float128_rem( float128, float128 STATUS_PARAM );
float128 float128_sqrt( float128 STATUS_PARAM );
int float128_eq( float128, float128 STATUS_PARAM );
int float128_le( float128, float128 STATUS_PARAM );
int float128_lt( float128, float128 STATUS_PARAM );
int float128_eq_signaling( float128, float128 STATUS_PARAM );
int float128_le_quiet( float128, float128 STATUS_PARAM );
int float128_lt_quiet( float128, float128 STATUS_PARAM );
int float128_compare( float128, float128 STATUS_PARAM );
int float128_compare_quiet( float128, float128 STATUS_PARAM );
int float128_is_nan( float128 );
int float128_is_signaling_nan( float128 );
float128 float128_scalbn( float128, int STATUS_PARAM );

INLINE float128 float128_abs(float128 a)
{
    a.high &= 0x7fffffffffffffffLL;
    return a;
}

INLINE float128 float128_chs(float128 a)
{
    a.high ^= 0x8000000000000000LL;
    return a;
}

INLINE int float128_is_infinity(float128 a)
{
    return (a.high & 0x7fffffffffffffffLL) == 0x7fff000000000000LL && a.low == 0;
}

INLINE int float128_is_neg(float128 a)
{
    return a.high >> 63;
}

INLINE int float128_is_zero(float128 a)
{
    return (a.high & 0x7fffffffffffffffLL) == 0 && a.low == 0;
}

#endif

#else /* CONFIG_SOFTFLOAT */

#include "softfloat-native.h"

#endif /* !CONFIG_SOFTFLOAT */

#endif /* !SOFTFLOAT_H */