softfloat.java

Java Op Processor java vhdl processor

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

This C source 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.

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

package com.jopdesign.sys;
/**
*	comments:
*		all 64 bit functions removed
*/

public class SoftFloat {

// processor include 
//typedef int flag;
//typedef int uint8;
//typedef int int8;
//typedef int uint16;
//typedef int int16;
//typedef unsigned int uint32;
//typedef signed int int32;
//#ifdef BITS64
//typedef unsigned long long int uint64;
//typedef signed long long int int64;
//#endif
//
///*----------------------------------------------------------------------------
//| 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 unsigned char bits8;
//typedef signed char sbits8;
//typedef unsigned short int bits16;
//typedef signed short int sbits16;
//typedef unsigned int bits32;
//typedef signed int sbits32;
//#ifdef BITS64
//typedef unsigned long long int bits64;
//typedef signed long long int sbits64;
//#endif

/*----------------------------------------------------------------------------
| The `LIT64' macro takes as its argument a textual integer literal and
// #include "milieu.h"
// #include "softfloat.h"

/*----------------------------------------------------------------------------
| Floating-point rounding mode and exception flags.
*----------------------------------------------------------------------------*/
// int8 float_rounding_mode = float_round_nearest_even;
// int8 float_exception_flags = 0;

/*----------------------------------------------------------------------------
| Primitive arithmetic functions, including multi-word arithmetic, and
| division and square root approximations.  (Can be specialized to target if
| desired.)
*----------------------------------------------------------------------------*/

// #include "softfloat-macros"
//
/*----------------------------------------------------------------------------
| Shifts `a' right by the number of bits given in `count'.  If any nonzero
| bits are shifted off, they are ``jammed'' into the least significant bit of
| the result by setting the least significant bit to 1.  The value of `count'
| can be arbitrarily large; in particular, if `count' is greater than 32, the
| result will be either 0 or 1, depending on whether `a' is zero or nonzero.
| The result is stored in the location pointed to by `zPtr'.
*----------------------------------------------------------------------------*/

//INLINE void shift32RightJamming( bits32 a, int16 count, bits32 *zPtr )
static int shift32RightJamming( int a, int count )
{
	// bits32 z;
	int z;

	if ( count == 0 ) {
		z = a;
	}
	else if ( count < 32 ) {
		z = ( a>>>count ) | (( ( a<<( ( -count ) & 31 ) ) != 0 ) ? 1 : 0);
	}
	else {
		z = ( a != 0 ) ? 1 : 0;
	}
//	*zPtr = z;
	return z;

}

///*----------------------------------------------------------------------------
//| Shifts the 64-bit value formed by concatenating `a0' and `a1' left by the
//| number of bits given in `count'.  Any bits shifted off are lost.  The value
//| of `count' must be less than 32.  The result is broken into two 32-bit
//| pieces which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// shortShift64Left(
//	 bits32 a0, bits32 a1, int16 count, bits32 *z0Ptr, bits32 *z1Ptr )
//{
//
//	*z1Ptr = a1<<count;
//	*z0Ptr =
//		( count == 0 ) ? a0 : ( a0<<count ) | ( a1>>( ( - count ) & 31 ) );
//
//}
///*----------------------------------------------------------------------------
//| Adds the 64-bit value formed by concatenating `a0' and `a1' to the 64-bit
//| value formed by concatenating `b0' and `b1'.  Addition is modulo 2^64, so
//| any carry out is lost.  The result is broken into two 32-bit pieces which
//| are stored at the locations pointed to by `z0Ptr' and `z1Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// add64(
//	 bits32 a0, bits32 a1, bits32 b0, bits32 b1, bits32 *z0Ptr, bits32 *z1Ptr )
//{
//	bits32 z1;
//
//	z1 = a1 + b1;
//	*z1Ptr = z1;
//	*z0Ptr = a0 + b0 + ( z1 < a1 );
//
//}
//
///*----------------------------------------------------------------------------
//| Adds the 96-bit value formed by concatenating `a0', `a1', and `a2' to the
//| 96-bit value formed by concatenating `b0', `b1', and `b2'.  Addition is
//| modulo 2^96, so any carry out is lost.  The result is broken into three
//| 32-bit pieces which are stored at the locations pointed to by `z0Ptr',
//| `z1Ptr', and `z2Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// add96(
//	 bits32 a0,
//	 bits32 a1,
//	 bits32 a2,
//	 bits32 b0,
//	 bits32 b1,
//	 bits32 b2,
//	 bits32 *z0Ptr,
//	 bits32 *z1Ptr,
//	 bits32 *z2Ptr
// )
//{
//	bits32 z0, z1, z2;
//	int8 carry0, carry1;
//
//	z2 = a2 + b2;
//	carry1 = ( z2 < a2 );
//	z1 = a1 + b1;
//	carry0 = ( z1 < a1 );
//	z0 = a0 + b0;
//	z1 += carry1;
//	z0 += ( z1 < carry1 );
//	z0 += carry0;
//	*z2Ptr = z2;
//	*z1Ptr = z1;
//	*z0Ptr = z0;
//
//}
//
///*----------------------------------------------------------------------------
//| Subtracts the 64-bit value formed by concatenating `b0' and `b1' from the
//| 64-bit value formed by concatenating `a0' and `a1'.  Subtraction is modulo
//| 2^64, so any borrow out (carry out) is lost.  The result is broken into two
//| 32-bit pieces which are stored at the locations pointed to by `z0Ptr' and
//| `z1Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// sub64(
//	 bits32 a0, bits32 a1, bits32 b0, bits32 b1, bits32 *z0Ptr, bits32 *z1Ptr )
//{
//
//	*z1Ptr = a1 - b1;
//	*z0Ptr = a0 - b0 - ( a1 < b1 );
//
//}
//
///*----------------------------------------------------------------------------
//| Subtracts the 96-bit value formed by concatenating `b0', `b1', and `b2' from
//| the 96-bit value formed by concatenating `a0', `a1', and `a2'.  Subtraction
//| is modulo 2^96, so any borrow out (carry out) is lost.  The result is broken
//| into three 32-bit pieces which are stored at the locations pointed to by
//| `z0Ptr', `z1Ptr', and `z2Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// sub96(
//	 bits32 a0,
//	 bits32 a1,
//	 bits32 a2,
//	 bits32 b0,
//	 bits32 b1,
//	 bits32 b2,
//	 bits32 *z0Ptr,
//	 bits32 *z1Ptr,
//	 bits32 *z2Ptr
// )
//{
//	bits32 z0, z1, z2;
//	int8 borrow0, borrow1;
//
//	z2 = a2 - b2;
//	borrow1 = ( a2 < b2 );
//	z1 = a1 - b1;
//	borrow0 = ( a1 < b1 );
//	z0 = a0 - b0;
//	z0 -= ( z1 < borrow1 );
//	z1 -= borrow1;
//	z0 -= borrow0;
//	*z2Ptr = z2;
//	*z1Ptr = z1;
//	*z0Ptr = z0;
//
//}
//
///*----------------------------------------------------------------------------
//| Multiplies `a' by `b' to obtain a 64-bit product.  The product is broken
//| into two 32-bit pieces which are stored at the locations pointed to by
//| `z0Ptr' and `z1Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void mul32To64( bits32 a, bits32 b, bits32 *z0Ptr, bits32 *z1Ptr )
//{
//	bits16 aHigh, aLow, bHigh, bLow;
//	bits32 z0, zMiddleA, zMiddleB, z1;
//
//	aLow = a;
//	aHigh = a>>16;
//	bLow = b;
//	bHigh = b>>16;
//	z1 = ( (bits32) aLow ) * bLow;
//	zMiddleA = ( (bits32) aLow ) * bHigh;
//	zMiddleB = ( (bits32) aHigh ) * bLow;
//	z0 = ( (bits32) aHigh ) * bHigh;
//	zMiddleA += zMiddleB;
//	z0 += ( ( (bits32) ( zMiddleA < zMiddleB ) )<<16 ) + ( zMiddleA>>16 );
//	zMiddleA <<= 16;
//	z1 += zMiddleA;
//	z0 += ( z1 < zMiddleA );
//	*z1Ptr = z1;
//	*z0Ptr = z0;
//
//}
//
///*----------------------------------------------------------------------------
//| Multiplies the 64-bit value formed by concatenating `a0' and `a1' by `b'
//| to obtain a 96-bit product.  The product is broken into three 32-bit pieces
//| which are stored at the locations pointed to by `z0Ptr', `z1Ptr', and
//| `z2Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// mul64By32To96(
//	 bits32 a0,
//	 bits32 a1,
//	 bits32 b,
//	 bits32 *z0Ptr,
//	 bits32 *z1Ptr,
//	 bits32 *z2Ptr
// )
//{
//	bits32 z0, z1, z2, more1;
//
//	mul32To64( a1, b, &z1, &z2 );
//	mul32To64( a0, b, &z0, &more1 );
//	add64( z0, more1, 0, z1, &z0, &z1 );
//	*z2Ptr = z2;
//	*z1Ptr = z1;
//	*z0Ptr = z0;
//
//}
//
///*----------------------------------------------------------------------------
//| Multiplies the 64-bit value formed by concatenating `a0' and `a1' to the
//| 64-bit value formed by concatenating `b0' and `b1' to obtain a 128-bit
//| product.  The product is broken into four 32-bit pieces which are stored at
//| the locations pointed to by `z0Ptr', `z1Ptr', `z2Ptr', and `z3Ptr'.
//*----------------------------------------------------------------------------*/
//
//INLINE void
// mul64To128(
//	 bits32 a0,
//	 bits32 a1,
//	 bits32 b0,
//	 bits32 b1,
//	 bits32 *z0Ptr,
//	 bits32 *z1Ptr,
//	 bits32 *z2Ptr,
//	 bits32 *z3Ptr
// )
//{
//	bits32 z0, z1, z2, z3;
//	bits32 more1, more2;
//
//	mul32To64( a1, b1, &z2, &z3 );
//	mul32To64( a1, b0, &z1, &more2 );
//	add64( z1, more2, 0, z2, &z1, &z2 );
//	mul32To64( a0, b0, &z0, &more1 );
//	add64( z0, more1, 0, z1, &z0, &z1 );
//	mul32To64( a0, b1, &more1, &more2 );
//	add64( more1, more2, 0, z2, &more1, &z2 );
//	add64( z0, z1, 0, more1, &z0, &z1 );
//	*z3Ptr = z3;
//	*z2Ptr = z2;
//	*z1Ptr = z1;
//	*z0Ptr = z0;
//
//}
//
///*----------------------------------------------------------------------------
//| Returns an approximation to the 32-bit integer quotient obtained by dividing
//| `b' into the 64-bit value formed by concatenating `a0' and `a1'.  The
//| divisor `b' must be at least 2^31.  If q is the exact quotient truncated
//| toward zero, the approximation returned lies between q and q + 2 inclusive.
//| If the exact quotient q is larger than 32 bits, the maximum positive 32-bit
//| unsigned integer is returned.
//*----------------------------------------------------------------------------*/
//
//static bits32 estimateDiv64To32( bits32 a0, bits32 a1, bits32 b )
//{
//	bits32 b0, b1;
//	bits32 rem0, rem1, term0, term1;
//	bits32 z;
//
//	if ( b <= a0 ) return 0xFFFFFFFF;
//	b0 = b>>16;
//	z = ( b0<<16 <= a0 ) ? 0xFFFF0000 : ( a0 / b0 )<<16;
//	mul32To64( b, z, &term0, &term1 );
//	sub64( a0, a1, term0, term1, &rem0, &rem1 );
//	while ( ( (sbits32) rem0 ) < 0 ) {
//		z -= 0x10000;
//		b1 = b<<16;
//		add64( rem0, rem1, b0, b1, &rem0, &rem1 );
//	}
//	rem0 = ( rem0<<16 ) | ( rem1>>16 );
//	z |= ( b0<<16 <= rem0 ) ? 0xFFFF : rem0 / b0;
//	return z;
//
//}
//
///*----------------------------------------------------------------------------
//| Returns an approximation to the square root of the 32-bit significand given
//| by `a'.  Considered as an integer, `a' must be at least 2^31.  If bit 0 of
//| `aExp' (the least significant bit) is 1, the integer returned approximates
//| 2^31*sqrt(`a'/2^31), where `a' is considered an integer.  If bit 0 of `aExp'
//| is 0, the integer returned approximates 2^31*sqrt(`a'/2^30).  In either
//| case, the approximation returned lies strictly within +/-2 of the exact
//| value.
//*----------------------------------------------------------------------------*/
//
//static bits32 estimateSqrt32( int16 aExp, bits32 a )
//{
//	static const bits16 sqrtOddAdjustments[] = {
//		0x0004, 0x0022, 0x005D, 0x00B1, 0x011D, 0x019F, 0x0236, 0x02E0,
//		0x039C, 0x0468, 0x0545, 0x0631, 0x072B, 0x0832, 0x0946, 0x0A67
//	};
//	static const bits16 sqrtEvenAdjustments[] = {
//		0x0A2D, 0x08AF, 0x075A, 0x0629, 0x051A, 0x0429, 0x0356, 0x029E,
//		0x0200, 0x0179, 0x0109, 0x00AF, 0x0068, 0x0034, 0x0012, 0x0002
//	};
//	int8 index;
//	bits32 z;
//
//	index = ( a>>27 ) & 15;
//	if ( aExp & 1 ) {
//		z = 0x4000 + ( a>>17 ) - sqrtOddAdjustments[ index ];
//		z = ( ( a / z )<<14 ) + ( z<<15 );
//		a >>= 1;
//	}
//	else {
//		z = 0x8000 + ( a>>17 ) - sqrtEvenAdjustments[ index ];
//		z = a / z + z;
//		z = ( 0x20000 <= z ) ? 0xFFFF8000 : ( z<<15 );
//		if ( z <= a ) return (bits32) ( ( (sbits32) a )>>1 );
//	}
//	return ( ( estimateDiv64To32( a, 0, z ) )>>1 ) + ( z>>1 );
//
//}
//
/*----------------------------------------------------------------------------
| Returns the number of leading 0 bits before the most-significant 1 bit of
| `a'.  If `a' is zero, 32 is returned.
*----------------------------------------------------------------------------*/

// static int8 countLeadingZeros32( bits32 a )
static int countLeadingZeros32( int a )
{
/*
	static const int8 countLeadingZerosHigh[] = {
		8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
		3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
		2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
		2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0