468 lines
12 KiB
C++
468 lines
12 KiB
C++
/* file: cvt_vax_f.c */
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/*
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**
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** COPYRIGHT (c) 1989, 1990 BY
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** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.
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** ALL RIGHTS RESERVED.
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**
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** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED
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** ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH THE
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** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER
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** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
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** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY
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** TRANSFERRED.
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**
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** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE
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** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT
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** CORPORATION.
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**
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** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS
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** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
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**
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*/
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/*
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**++
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** Facility:
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**
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** CVT Run-Time Library
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**
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** Abstract:
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**
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** This module contains routines to convert VAX F_Float floating
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** point data into other supported floating point formats.
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**
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** Authors:
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**
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** Math RTL
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**
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** Creation Date: December 5, 1989.
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**
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** Modification History:
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**
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** 1-001 Original created. MRTL 5-Dec-1989.
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** 1-002 Add VMS and F77 bindings. TS 26-Mar-1990.
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**
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**--
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*/
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/*
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**
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** TABLE OF CONTENTS
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**
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** cvt_vax_f_to_cray
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** cvt_vax_f_to_ibm_short
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** cvt_vax_f_to_ieee_single
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**
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*/
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#include <stdio.h>
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#include <sysinc.h>
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#include <rpc.h>
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#include "cvt.h"
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#include "cvtpvt.h"
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//
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// Added for the MS NT environment
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//
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#include <stdlib.h>
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/*
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* C binding
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*/
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void cvt_vax_f_to_ieee_single(
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CVT_VAX_F input_value,
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CVT_SIGNED_INT options,
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CVT_IEEE_SINGLE output_value
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)
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{
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int i, round_bit_position;
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UNPACKED_REAL r;
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switch ( options & ~(CVT_C_BIG_ENDIAN | CVT_C_ERR_UNDERFLOW) ) {
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case 0 : options |= CVT_C_ROUND_TO_NEAREST;
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case CVT_C_ROUND_TO_NEAREST :
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case CVT_C_TRUNCATE :
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case CVT_C_ROUND_TO_POS :
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case CVT_C_ROUND_TO_NEG :
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case CVT_C_VAX_ROUNDING : break;
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default : RAISE(cvt__invalid_option);
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}
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// ===========================================================================
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//
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// This file used to be included as a separate file.
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//#include "unp_vaxf.c"
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//
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// ===========================================================================
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/* file: unpack_vax_f.c */
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/*
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**
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** COPYRIGHT (c) 1989 BY
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** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.
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** ALL RIGHTS RESERVED.
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**
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** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED
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** ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH THE
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** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER
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** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
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** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY
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** TRANSFERRED.
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**
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** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE
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** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT
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** CORPORATION.
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**
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** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS
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** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
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**
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*/
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/*
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**++
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** Facility:
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**
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** CVT Run-Time Library
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**
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** Abstract:
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**
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** This module contains code to extract information from a VAX
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** f_floating number and to initialize an UNPACKED_REAL structure
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** with those bits.
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**
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** This module is meant to be used as an include file.
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**
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** Author: Math RTL
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**
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** Creation Date: November 24, 1989.
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**
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** Modification History:
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**
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**--
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*/
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/*
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**++
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** Functional Description:
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**
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** This module contains code to extract information from a VAX
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** f_floating number and to initialize an UNPACKED_REAL structure
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** with those bits.
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**
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** See the header files for a description of the UNPACKED_REAL
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** structure.
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**
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** A VAX f_floating number in (16 bit words) looks like:
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**
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** [0]: Sign bit, 8 exp bits (bias 128), 7 fraction bits
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** [1]: 16 more fraction bits
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**
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** 0.5 <= fraction < 1.0, MSB implicit
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**
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**
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** Implicit parameters:
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**
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** input_value: a pointer to the input parameter.
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**
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** r: an UNPACKED_REAL structure
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**
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**--
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*/
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RpcpMemoryCopy(&r[1], input_value, 4);
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/* Initialize FLAGS and perhaps set NEGATIVE bit */
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r[U_R_FLAGS] = (r[1] >> 15) & U_R_NEGATIVE;
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/* Extract VAX biased exponent */
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r[U_R_EXP] = (r[1] >> 7) & 0x000000FFL;
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if (r[U_R_EXP] == 0) {
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if (r[U_R_FLAGS])
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r[U_R_FLAGS] |= U_R_INVALID;
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else
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r[U_R_FLAGS] = U_R_ZERO;
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} else {
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/* Adjust for VAX 16 bit floating format */
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r[1] = ((r[1] << 16) | (r[1] >> 16));
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/* Add unpacked real bias and subtract VAX bias */
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r[U_R_EXP] += (U_R_BIAS - 128);
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/* Set hidden bit */
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r[1] |= 0x00800000L;
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/* Left justify fraction bits */
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r[1] <<= 8;
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/* Clear uninitialized parts for unpacked real */
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r[2] = 0;
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r[3] = 0;
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r[4] = 0;
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}
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// end of file: unpack_vax_f.c
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//
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// ===========================================================================
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//
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// This file used to be included as a separate file.
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//#include "pack_ies.c"
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//
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// ===========================================================================
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/* file: pack_ieee_s.c */
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/*
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**
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** COPYRIGHT (c) 1989 BY
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** DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS.
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** ALL RIGHTS RESERVED.
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**
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** THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED
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** ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH THE
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** INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS SOFTWARE OR ANY OTHER
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** COPIES THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
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** OTHER PERSON. NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY
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** TRANSFERRED.
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**
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** THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE
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** AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT
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** CORPORATION.
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**
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** DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY OF ITS
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** SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
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**
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*/
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/*
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**++
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** Facility:
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**
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** CVT Run-Time Library
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**
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** Abstract:
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**
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** This module contains code to extract information from an
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** UNPACKED_REAL structure and to create an IEEE single floating number
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** with those bits.
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**
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** This module is meant to be used as an include file.
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**
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** Author: Math RTL
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**
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** Creation Date: November 24, 1989.
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**
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** Modification History:
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**
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**--
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*/
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/*
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**++
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** Functional Description:
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**
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** This module contains code to extract information from an
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** UNPACKED_REAL structure and to create an IEEE single number
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** with those bits.
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**
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** See the header files for a description of the UNPACKED_REAL
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** structure.
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**
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** A normalized IEEE single precision floating number looks like:
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**
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** Sign bit, 8 exp bits (bias 127), 23 fraction bits
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**
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** 1.0 <= fraction < 2.0, MSB implicit
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**
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** For more details see "Mips R2000 Risc Architecture"
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** by Gerry Kane, page 6-8 or ANSI/IEEE Std 754-1985.
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**
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**
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** Implicit parameters:
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**
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** options: a word of flags, see include files.
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**
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** output_value: a pointer to the input parameter.
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**
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** r: an UNPACKED_REAL structure.
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**
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**--
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*/
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if (r[U_R_FLAGS] & U_R_UNUSUAL) {
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if (r[U_R_FLAGS] & U_R_ZERO)
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if (r[U_R_FLAGS] & U_R_NEGATIVE)
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RpcpMemoryCopy(output_value, IEEE_S_NEG_ZERO, 4);
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else
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RpcpMemoryCopy(output_value, IEEE_S_POS_ZERO, 4);
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else if (r[U_R_FLAGS] & U_R_INFINITY) {
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if (r[U_R_FLAGS] & U_R_NEGATIVE)
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RpcpMemoryCopy(output_value, IEEE_S_NEG_INFINITY, 4);
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else
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RpcpMemoryCopy(output_value, IEEE_S_POS_INFINITY, 4);
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} else if (r[U_R_FLAGS] & U_R_INVALID) {
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RpcpMemoryCopy(output_value, IEEE_S_INVALID, 4);
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RAISE(cvt__invalid_value);
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}
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} else {
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/* Precision varies if value will be a denorm */
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/* So, figure out where to round (0 <= i <= 24). */
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round_bit_position = r[U_R_EXP] - ((U_R_BIAS - 126) - 23);
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if (round_bit_position < 0)
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round_bit_position = 0;
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else if (round_bit_position > 24)
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round_bit_position = 24;
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#include "round.cxx"
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if (r[U_R_EXP] < (U_R_BIAS - 125)) {
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/* Denorm or underflow */
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if (r[U_R_EXP] < ((U_R_BIAS - 125) - 23)) {
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/* Value is too small for a denorm, so underflow */
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if (r[U_R_FLAGS] & U_R_NEGATIVE)
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RpcpMemoryCopy(output_value, IEEE_S_NEG_ZERO, 4);
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else
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RpcpMemoryCopy(output_value, IEEE_S_POS_ZERO, 4);
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if (options & CVT_C_ERR_UNDERFLOW) {
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RAISE(cvt__underflow);
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}
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} else {
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/* Figure leading zeros for denorm and right-justify fraction */
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i = 32 - (r[U_R_EXP] - ((U_R_BIAS - 126) - 23));
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r[1] >>= i;
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/* Set sign bit */
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r[1] |= (r[U_R_FLAGS] << 31);
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if (options & CVT_C_BIG_ENDIAN) {
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r[0] = ((r[1] << 24) | (r[1] >> 24));
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r[0] |= ((r[1] << 8) & 0x00FF0000L);
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r[0] |= ((r[1] >> 8) & 0x0000FF00L);
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RpcpMemoryCopy(output_value, r, 4);
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} else {
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RpcpMemoryCopy(output_value, &r[1], 4);
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}
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}
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} else if (r[U_R_EXP] > (U_R_BIAS + 128)) {
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/* Overflow */
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if (options & CVT_C_TRUNCATE) {
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if (r[U_R_FLAGS] & U_R_NEGATIVE)
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RpcpMemoryCopy(output_value, IEEE_S_NEG_HUGE, 4);
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else
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RpcpMemoryCopy(output_value, IEEE_S_POS_HUGE, 4);
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} else if ((options & CVT_C_ROUND_TO_POS)
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&& (r[U_R_FLAGS] & U_R_NEGATIVE)) {
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RpcpMemoryCopy(output_value, IEEE_S_NEG_HUGE, 4);
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} else if ((options & CVT_C_ROUND_TO_NEG)
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&& !(r[U_R_FLAGS] & U_R_NEGATIVE)) {
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RpcpMemoryCopy(output_value, IEEE_S_POS_HUGE, 4);
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} else {
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if (r[U_R_FLAGS] & U_R_NEGATIVE)
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RpcpMemoryCopy(output_value, IEEE_S_NEG_INFINITY, 4);
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else
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RpcpMemoryCopy(output_value, IEEE_S_POS_INFINITY, 4);
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}
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RAISE(cvt__overflow);
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} else {
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/* Adjust bias of exponent */
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r[U_R_EXP] -= (U_R_BIAS - 126);
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/* Make room for exponent and sign bit */
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r[1] >>= 8;
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/* Clear implicit bit */
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r[1] &= 0x007FFFFFL;
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/* OR in exponent and sign bit */
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r[1] |= (r[U_R_EXP] << 23);
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r[1] |= (r[U_R_FLAGS] << 31);
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if (options & CVT_C_BIG_ENDIAN) {
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r[0] = ((r[1] << 24) | (r[1] >> 24));
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r[0] |= ((r[1] << 8) & 0x00FF0000L);
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r[0] |= ((r[1] >> 8) & 0x0000FF00L);
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RpcpMemoryCopy(output_value, r, 4);
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} else {
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RpcpMemoryCopy(output_value, &r[1], 4);
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}
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}
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}
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// end of file: pack_ies.c
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}
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