/*
   * Linux/PA-RISC Project (http://www.parisc-linux.org/)
   *
   * Floating-point emulation code
   *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
   *
   *    This program is free software; you can redistribute it and/or modify
   *    it under the terms of the GNU General Public License as published by
   *    the Free Software Foundation; either version 2, or (at your option)
   *    any later version.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU General Public License for more details.
   *
   *    You should have received a copy of the GNU General Public License
   *    along with this program; if not, write to the Free Software
   *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  /*
   * BEGIN_DESC
   *
   *  File:
   *	@(#)	pa/spmath/fcnvxf.c		$Revision: 1.1 $
   *
   *  Purpose:
   *	Single Fixed-point to Single Floating-point
   *	Single Fixed-point to Double Floating-point 
   *	Double Fixed-point to Single Floating-point 
   *	Double Fixed-point to Double Floating-point 
   *
   *  External Interfaces:
   *	dbl_to_dbl_fcnvxf(srcptr,nullptr,dstptr,status)
   *	dbl_to_sgl_fcnvxf(srcptr,nullptr,dstptr,status)
   *	sgl_to_dbl_fcnvxf(srcptr,nullptr,dstptr,status)
   *	sgl_to_sgl_fcnvxf(srcptr,nullptr,dstptr,status)
   *
   *  Internal Interfaces:
   *
   *  Theory:
   *	<<please update with a overview of the operation of this file>>
   *
   * END_DESC
  */
  
  
  #include "float.h"
  #include "sgl_float.h"
  #include "dbl_float.h"
  #include "cnv_float.h"
  
  /*
   *  Convert single fixed-point to single floating-point format
   */
  
  int
  sgl_to_sgl_fcnvxf(
  		    int *srcptr,
  		    unsigned int *nullptr,
  		    sgl_floating_point *dstptr,
  		    unsigned int *status)
  {
  	register int src, dst_exponent;
  	register unsigned int result = 0;
  
  	src = *srcptr;
  	/* 
  	 * set sign bit of result and get magnitude of source 
  	 */
  	if (src < 0) {
  		Sgl_setone_sign(result);  
  		Int_negate(src);
  	}
  	else {
  		Sgl_setzero_sign(result);
          	/* Check for zero */ 
          	if (src == 0) { 
                  	Sgl_setzero(result); 
  			*dstptr = result;
                  	return(NOEXCEPTION); 
          	} 
  	}
  	/*
  	 * Generate exponent and normalized mantissa
  	 */
  	dst_exponent = 16;    /* initialize for normalization */
  	/*
  	 * Check word for most significant bit set.  Returns
  	 * a value in dst_exponent indicating the bit position,
  	 * between -1 and 30.
  	 */
  	Find_ms_one_bit(src,dst_exponent);
  	/*  left justify source, with msb at bit position 1  */
  	if (dst_exponent >= 0) src <<= dst_exponent;
  	else src = 1 << 30;
  	Sgl_set_mantissa(result, src >> (SGL_EXP_LENGTH-1));
  	Sgl_set_exponent(result, 30+SGL_BIAS - dst_exponent);
  
  	/* check for inexact */
  	if (Int_isinexact_to_sgl(src)) {
  		switch (Rounding_mode()) {
  			case ROUNDPLUS: 
  				if (Sgl_iszero_sign(result)) 
  					Sgl_increment(result);
  				break;
  			case ROUNDMINUS: 
  				if (Sgl_isone_sign(result)) 
  					Sgl_increment(result);
  				break;
  			case ROUNDNEAREST:
  				Sgl_roundnearest_from_int(src,result);
  		}
  		if (Is_inexacttrap_enabled()) {
  			*dstptr = result;
  			return(INEXACTEXCEPTION);
  		}
  		else Set_inexactflag();
  	}
  	*dstptr = result;
  	return(NOEXCEPTION);
  }
  
  /*
   *  Single Fixed-point to Double Floating-point 
   */
  
  int
  sgl_to_dbl_fcnvxf(
  		    int *srcptr,
  		    unsigned int *nullptr,
  		    dbl_floating_point *dstptr,
  		    unsigned int *status)
  {
  	register int src, dst_exponent;
  	register unsigned int resultp1 = 0, resultp2 = 0;
  
  	src = *srcptr;
  	/* 
  	 * set sign bit of result and get magnitude of source 
  	 */
  	if (src < 0) {
  		Dbl_setone_sign(resultp1);  
  		Int_negate(src);
  	}
  	else {
  		Dbl_setzero_sign(resultp1);
          	/* Check for zero */
          	if (src == 0) {
                  	Dbl_setzero(resultp1,resultp2);
                  	Dbl_copytoptr(resultp1,resultp2,dstptr);
                  	return(NOEXCEPTION);
          	}
  	}
  	/*
  	 * Generate exponent and normalized mantissa
  	 */
  	dst_exponent = 16;    /* initialize for normalization */
  	/*
  	 * Check word for most significant bit set.  Returns
  	 * a value in dst_exponent indicating the bit position,
  	 * between -1 and 30.
  	 */
  	Find_ms_one_bit(src,dst_exponent);
  	/*  left justify source, with msb at bit position 1  */
  	if (dst_exponent >= 0) src <<= dst_exponent;
  	else src = 1 << 30;
  	Dbl_set_mantissap1(resultp1, src >> DBL_EXP_LENGTH - 1);
  	Dbl_set_mantissap2(resultp2, src << (33-DBL_EXP_LENGTH));
  	Dbl_set_exponent(resultp1, (30+DBL_BIAS) - dst_exponent);
  	Dbl_copytoptr(resultp1,resultp2,dstptr);
  	return(NOEXCEPTION);
  }
  
  /*
   *  Double Fixed-point to Single Floating-point 
   */
  
  int
  dbl_to_sgl_fcnvxf(
  			dbl_integer *srcptr,
  			unsigned int *nullptr,
  			sgl_floating_point *dstptr,
  			unsigned int *status)
  {
  	int dst_exponent, srcp1;
  	unsigned int result = 0, srcp2;
  
  	Dint_copyfromptr(srcptr,srcp1,srcp2);
  	/* 
  	 * set sign bit of result and get magnitude of source 
  	 */
  	if (srcp1 < 0) {
  		Sgl_setone_sign(result);  
  		Dint_negate(srcp1,srcp2);
  	}
  	else {
  		Sgl_setzero_sign(result);
          	/* Check for zero */
          	if (srcp1 == 0 && srcp2 == 0) {
                  	Sgl_setzero(result);
                  	*dstptr = result;
                  	return(NOEXCEPTION);
  		}
          }
  	/*
  	 * Generate exponent and normalized mantissa
  	 */
  	dst_exponent = 16;    /* initialize for normalization */
  	if (srcp1 == 0) {
  		/*
  		 * Check word for most significant bit set.  Returns
  		 * a value in dst_exponent indicating the bit position,
  		 * between -1 and 30.
  		 */
  		Find_ms_one_bit(srcp2,dst_exponent);
  		/*  left justify source, with msb at bit position 1  */
  		if (dst_exponent >= 0) {
  			srcp1 = srcp2 << dst_exponent;    
  			srcp2 = 0;
  		}
  		else {
  			srcp1 = srcp2 >> 1;
  			srcp2 <<= 31; 
  		}
  		/*
  		 *  since msb set is in second word, need to 
  		 *  adjust bit position count
  		 */
  		dst_exponent += 32;
  	}
  	else {
  		/*
  		 * Check word for most significant bit set.  Returns
  		 * a value in dst_exponent indicating the bit position,
  		 * between -1 and 30.
  		 *
  		 */
  		Find_ms_one_bit(srcp1,dst_exponent);
  		/*  left justify source, with msb at bit position 1  */
  		if (dst_exponent > 0) {
  			Variable_shift_double(srcp1,srcp2,(32-dst_exponent),
  			 srcp1); 
  			srcp2 <<= dst_exponent;
  		}
  		/*
  		 * If dst_exponent = 0, we don't need to shift anything.
  		 * If dst_exponent = -1, src = - 2**63 so we won't need to 
  		 * shift srcp2.
  		 */
  		else srcp1 >>= -(dst_exponent);
  	}
  	Sgl_set_mantissa(result, srcp1 >> SGL_EXP_LENGTH - 1);
  	Sgl_set_exponent(result, (62+SGL_BIAS) - dst_exponent);
  
  	/* check for inexact */
  	if (Dint_isinexact_to_sgl(srcp1,srcp2)) {
  		switch (Rounding_mode()) {
  			case ROUNDPLUS: 
  				if (Sgl_iszero_sign(result)) 
  					Sgl_increment(result);
  				break;
  			case ROUNDMINUS: 
  				if (Sgl_isone_sign(result)) 
  					Sgl_increment(result);
  				break;
  			case ROUNDNEAREST:
  				Sgl_roundnearest_from_dint(srcp1,srcp2,result);
  		}
  		if (Is_inexacttrap_enabled()) {
  			*dstptr = result;
  			return(INEXACTEXCEPTION);
  		}
  		else Set_inexactflag();
  	}
  	*dstptr = result;
  	return(NOEXCEPTION);
  }
  
  /*
   *  Double Fixed-point to Double Floating-point 
   */
  
  int
  dbl_to_dbl_fcnvxf(
  		    dbl_integer *srcptr,
  		    unsigned int *nullptr,
  		    dbl_floating_point *dstptr,
  		    unsigned int *status)
  {
  	register int srcp1, dst_exponent;
  	register unsigned int srcp2, resultp1 = 0, resultp2 = 0;
  
  	Dint_copyfromptr(srcptr,srcp1,srcp2);
  	/* 
  	 * set sign bit of result and get magnitude of source 
  	 */
  	if (srcp1 < 0) {
  		Dbl_setone_sign(resultp1);
  		Dint_negate(srcp1,srcp2);
  	}
  	else {
  		Dbl_setzero_sign(resultp1);
          	/* Check for zero */
          	if (srcp1 == 0 && srcp2 ==0) {
                  	Dbl_setzero(resultp1,resultp2);
                  	Dbl_copytoptr(resultp1,resultp2,dstptr);
                  	return(NOEXCEPTION);
  		}
          }
  	/*
  	 * Generate exponent and normalized mantissa
  	 */
  	dst_exponent = 16;    /* initialize for normalization */
  	if (srcp1 == 0) {
  		/*
  		 * Check word for most significant bit set.  Returns
  		 * a value in dst_exponent indicating the bit position,
  		 * between -1 and 30.
  		 */
  		Find_ms_one_bit(srcp2,dst_exponent);
  		/*  left justify source, with msb at bit position 1  */
  		if (dst_exponent >= 0) {
  			srcp1 = srcp2 << dst_exponent;    
  			srcp2 = 0;
  		}
  		else {
  			srcp1 = srcp2 >> 1;
  			srcp2 <<= 31;
  		}
  		/*
  		 *  since msb set is in second word, need to 
  		 *  adjust bit position count
  		 */
  		dst_exponent += 32;
  	}
  	else {
  		/*
  		 * Check word for most significant bit set.  Returns
  		 * a value in dst_exponent indicating the bit position,
  		 * between -1 and 30.
  		 */
  		Find_ms_one_bit(srcp1,dst_exponent);
  		/*  left justify source, with msb at bit position 1  */
  		if (dst_exponent > 0) {
  			Variable_shift_double(srcp1,srcp2,(32-dst_exponent),
  			 srcp1); 
  			srcp2 <<= dst_exponent;
  		}
  		/*
  		 * If dst_exponent = 0, we don't need to shift anything.
  		 * If dst_exponent = -1, src = - 2**63 so we won't need to 
  		 * shift srcp2.
  		 */
  		else srcp1 >>= -(dst_exponent);
  	}
  	Dbl_set_mantissap1(resultp1, srcp1 >> (DBL_EXP_LENGTH-1));
  	Shiftdouble(srcp1,srcp2,DBL_EXP_LENGTH-1,resultp2);
  	Dbl_set_exponent(resultp1, (62+DBL_BIAS) - dst_exponent);
  
  	/* check for inexact */
  	if (Dint_isinexact_to_dbl(srcp2)) {
  		switch (Rounding_mode()) {
  			case ROUNDPLUS: 
  				if (Dbl_iszero_sign(resultp1)) {
  					Dbl_increment(resultp1,resultp2);
  				}
  				break;
  			case ROUNDMINUS: 
  				if (Dbl_isone_sign(resultp1)) {
  					Dbl_increment(resultp1,resultp2);
  				}
  				break;
  			case ROUNDNEAREST:
  				Dbl_roundnearest_from_dint(srcp2,resultp1,
  				resultp2);
  		}
  		if (Is_inexacttrap_enabled()) {
  			Dbl_copytoptr(resultp1,resultp2,dstptr);
  			return(INEXACTEXCEPTION);
  		}
  		else Set_inexactflag();
  	}
  	Dbl_copytoptr(resultp1,resultp2,dstptr);
  	return(NOEXCEPTION);
  }