|
|
/* file: cvt_vax_g.c */
/*
**** COPYRIGHT (c) 1989, 1990 BY** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.** ALL RIGHTS RESERVED.**** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED** ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH THE** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY** TRANSFERRED.**** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT** CORPORATION.**** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.***/
/*
**++** Facility:**** CVT Run-Time Library**** Abstract:**** This module contains routines to convert VAX G_Float floating** point data into other supported floating point formats.**** Authors:**** Math RTL**** Creation Date: December 5, 1989.**** Modification History:**** 1-001 Original created. MRTL 5-Dec-1989.** 1-002 Add VMS and F77 bindings. TS 26-Mar-1990.****--*/
/*
**** TABLE OF CONTENTS**** cvt_vax_g_to_cray** cvt_vax_g_to_ibm_long** cvt_vax_g_to_ieee_double***/
#include <stdio.h>
#include <sysinc.h>
#include <rpc.h>
#include "cvt.h"
#include "cvtpvt.h"
//
// Added for the MS NT environment
//
#include <stdlib.h>
/*
**** Routine:**** cvt_vax_g_to_ieee_double**** Functional Description:**** This routine converts a VAX G_Float floating point number** into an IEEE double precision floating point number.**** Formal Parameters:**** input_value A VAX G_Float floating point number.**** options An integer bit mask. Set bits in the mask represent** selected routine options. Applicable options are:**** CVT_C_BIG_ENDIAN - default is little endian** CVT_C_ERR_UNDERFLOW - Raise underflows** CVT_C_TRUNCATE - truncate** CVT_C_ROUND_TO_POS - round to +infinity** CVT_C_ROUND_TO_NEG - round to -infinity** CVT_C_ROUND_TO_NEAREST - round to nearest** CVT_C_VAX_ROUNDING - VAX rounding**** NOTE: If no rounding mode is selected the following** default rounding mode is assumed:**** CVT_C_ROUND_TO_NEAREST.**** output_value The IEEE double precision representation of the VAX** G_Float number.**** Side Effects/Signaled Errors:**** cvt__invalid_value - an invalid input value was specified.** cvt__invalid_option - an invalid option was specified.** cvt__underflow - an underlow occurred during conversion while** Raise underflow was set.***/
/*
* C binding */void cvt_vax_g_to_ieee_double( CVT_VAX_G input_value, CVT_SIGNED_INT options, CVT_IEEE_DOUBLE output_value ){ int i, round_bit_position; UNPACKED_REAL r;
switch ( options & ~(CVT_C_BIG_ENDIAN | CVT_C_ERR_UNDERFLOW) ) { case 0 : options |= CVT_C_ROUND_TO_NEAREST; case CVT_C_ROUND_TO_NEAREST : case CVT_C_TRUNCATE : case CVT_C_ROUND_TO_POS : case CVT_C_ROUND_TO_NEG : case CVT_C_VAX_ROUNDING : break; default : RAISE(cvt__invalid_option); }
// ===========================================================================
//
// This file used to be included as a separate file.
//#include "unp_vaxg.c"
//
// ===========================================================================
/* file: unpack_vax_g.c */
/*
**** COPYRIGHT (c) 1989 BY** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.** ALL RIGHTS RESERVED.**** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED** ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH THE** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY** TRANSFERRED.**** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT** CORPORATION.**** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.***/
/*
**++** Facility:**** CVT Run-Time Library**** Abstract:**** This module contains code to extract information from a VAX** g_floating number and to initialize an UNPACKED_REAL structure** with those bits.**** This module is meant to be used as an include file.**** Author: Math RTL**** Creation Date: November 24, 1989.**** Modification History:****--*/
/*
**++** Functional Description:**** This module contains code to extract information from a VAX** g_floating number and to initialize an UNPACKED_REAL structure** with those bits.**** See the header files for a description of the UNPACKED_REAL** structure.** ** A VAX g_floating number in (16 bit words) looks like:** ** [0]: Sign bit, 11 exp bits (bias 1024), 4 fraction bits** [1]: 16 more fraction bits** [2]: 16 more fraction bits** [3]: 16 more fraction bits**** 0.5 <= fraction < 1.0, MSB implicit****** Implicit parameters:**** input_value: a pointer to the input parameter.**** r: an UNPACKED_REAL structure****--*/
RpcpMemoryCopy(&r[1], input_value, 8);
/* Initialize FLAGS and perhaps set NEGATIVE bit */
r[U_R_FLAGS] = (r[1] >> 15) & U_R_NEGATIVE;
/* Extract VAX biased exponent */
r[U_R_EXP] = (r[1] >> 4) & 0x000007FFL;
if (r[U_R_EXP] == 0) {
if (r[U_R_FLAGS]) r[U_R_FLAGS] |= U_R_INVALID; else r[U_R_FLAGS] = U_R_ZERO;
} else {
/* Adjust for VAX 16 bit floating format */
r[1] = ((r[1] << 16) | (r[1] >> 16)); r[2] = ((r[2] << 16) | (r[2] >> 16));
/* Add unpacked real bias and subtract VAX bias */
r[U_R_EXP] += (U_R_BIAS - 1024);
/* Set hidden bit */
r[1] |= 0x00100000L;
/* Left justify fraction bits */
r[1] <<= 11; r[1] |= (r[2] >> 21); r[2] <<= 11;
/* Clear uninitialized part of unpacked real */
r[3] = 0; r[4] = 0;
}
// end of file: unpack_vax_g.c
//
// ===========================================================================
//
// This file used to be included as a separate file.
//#include "pack_iet.c"
//
// ===========================================================================
/* file: pack_ieee_t.c */
/*
**** COPYRIGHT (c) 1989 BY** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.** ALL RIGHTS RESERVED.**** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED** ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH THE** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY** TRANSFERRED.**** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT** CORPORATION.**** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.***/
/*
**++** Facility:**** CVT Run-Time Library**** Abstract:**** This module contains code to extract information from an** UNPACKED_REAL structure and to create an IEEE double floating number** with those bits.**** This module is meant to be used as an include file.**** Author: Math RTL**** Creation Date: November 24, 1989.**** Modification History:****--*/
/*
**++** Functional Description:**** This module contains code to extract information from an** UNPACKED_REAL structure and to create an IEEE double floating number** with those bits.**** See the header files for a description of the UNPACKED_REAL** structure.**** A normalized IEEE double precision floating number looks like:**** [0]: 32 low order fraction bits** [1]: Sign bit, 11 exp bits (bias 1023), 20 fraction bits**** 1.0 <= fraction < 2.0, MSB implicit**** For more details see "Mips R2000 Risc Architecture"** by Gerry Kane, page 6-8 or ANSI/IEEE Std 754-1985.****** Implicit parameters:**** options: a word of flags, see include files.**** output_value: a pointer to the input parameter.**** r: an UNPACKED_REAL structure.**** i: a temporary integer variable****--*/
if (r[U_R_FLAGS] & U_R_UNUSUAL) {
if (r[U_R_FLAGS] & U_R_ZERO)
if (r[U_R_FLAGS] & U_R_NEGATIVE) RpcpMemoryCopy(output_value, IEEE_T_NEG_ZERO, 8); else RpcpMemoryCopy(output_value, IEEE_T_POS_ZERO, 8);
else if (r[U_R_FLAGS] & U_R_INFINITY) {
if (r[U_R_FLAGS] & U_R_NEGATIVE) RpcpMemoryCopy(output_value, IEEE_T_NEG_INFINITY, 8); else RpcpMemoryCopy(output_value, IEEE_T_POS_INFINITY, 8);
} else if (r[U_R_FLAGS] & U_R_INVALID) {
RpcpMemoryCopy(output_value, IEEE_T_INVALID, 8); RAISE(cvt__invalid_value);
}
} else {
/* Precision varies if value will be a denorm */ /* So, figure out where to round (0 <= i <= 53). */
round_bit_position = r[U_R_EXP] - ((U_R_BIAS - 1022) - 52); if (round_bit_position < 0) round_bit_position = 0; else if (round_bit_position > 53) round_bit_position = 53;
#include "round.cxx"
if (r[U_R_EXP] < (U_R_BIAS - 1021)) {
/* Denorm or underflow */
if (r[U_R_EXP] < ((U_R_BIAS - 1021) - 52)) {
/* Value is too small for a denorm, so underflow */
if (r[U_R_FLAGS] & U_R_NEGATIVE) RpcpMemoryCopy(output_value, IEEE_T_NEG_ZERO, 8); else RpcpMemoryCopy(output_value, IEEE_T_POS_ZERO, 8); if (options & CVT_C_ERR_UNDERFLOW) { RAISE(cvt__underflow); }
} else {
/* Figure leading zeros for denorm and right-justify fraction */
i = 64 - (r[U_R_EXP] - ((U_R_BIAS - 1022) - 52));
if (i > 31) { i -= 32; r[2] = (r[1] >> i); r[1] = 0; } else { r[2] >>= i; r[2] |= (r[1] << (32 - i)); r[1] >>= i; }
/* OR in sign bit */
r[1] |= (r[U_R_FLAGS] << 31);
if (options & CVT_C_BIG_ENDIAN) {
r[0] = ((r[1] << 24) | (r[1] >> 24)); r[0] |= ((r[1] << 8) & 0x00FF0000L); r[0] |= ((r[1] >> 8) & 0x0000FF00L); r[1] = ((r[2] << 24) | (r[2] >> 24)); r[1] |= ((r[2] << 8) & 0x00FF0000L); r[1] |= ((r[2] >> 8) & 0x0000FF00L);
} else {
r[0] = r[2];
}
RpcpMemoryCopy(output_value, r, 8); }
} else if (r[U_R_EXP] > (U_R_BIAS + 1024)) {
/* Overflow */
if (options & CVT_C_TRUNCATE) {
if (r[U_R_FLAGS] & U_R_NEGATIVE) RpcpMemoryCopy(output_value, IEEE_T_NEG_HUGE, 8); else RpcpMemoryCopy(output_value, IEEE_T_POS_HUGE, 8);
} else if ((options & CVT_C_ROUND_TO_POS) && (r[U_R_FLAGS] & U_R_NEGATIVE)) {
RpcpMemoryCopy(output_value, IEEE_T_NEG_HUGE, 8);
} else if ((options & CVT_C_ROUND_TO_NEG) && !(r[U_R_FLAGS] & U_R_NEGATIVE)) {
RpcpMemoryCopy(output_value, IEEE_T_POS_HUGE, 8);
} else {
if (r[U_R_FLAGS] & U_R_NEGATIVE) RpcpMemoryCopy(output_value, IEEE_T_NEG_INFINITY, 8); else RpcpMemoryCopy(output_value, IEEE_T_POS_INFINITY, 8);
}
RAISE(cvt__overflow);
} else {
/* Adjust bias of exponent */
r[U_R_EXP] -= (U_R_BIAS - 1022);
/* Make room for exponent and sign bit */
r[2] >>= 11; r[2] |= (r[1] << 21); r[1] >>= 11;
/* Clear implicit bit */
r[1] &= 0x000FFFFFL;
/* OR in exponent and sign bit */
r[1] |= (r[U_R_EXP] << 20); r[1] |= (r[U_R_FLAGS] << 31);
if (options & CVT_C_BIG_ENDIAN) {
r[0] = ((r[1] << 24) | (r[1] >> 24)); r[0] |= ((r[1] << 8) & 0x00FF0000L); r[0] |= ((r[1] >> 8) & 0x0000FF00L); r[1] = ((r[2] << 24) | (r[2] >> 24)); r[1] |= ((r[2] << 8) & 0x00FF0000L); r[1] |= ((r[2] >> 8) & 0x0000FF00L);
} else {
r[0] = r[2];
}
RpcpMemoryCopy(output_value, r, 8); }
}
// end of file: pack_iet.c
}
|
