Files
TeslaRel410/BORLAND/BC45/SOURCE/RTL/SOURCE/MATHLIB/FREXPL.CAS
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CydandClaude Fable 5 63312e07f9 source410: literal 4.10 source reconstruction + BC++ 4.52 fleet toolchain archived
- BORLAND/: Borland C++ 4.52 (chosen over 4.5 by byte-match: CODE/RP/CW32.LIB
  is identical to 4.52's install lib). BCC32/TLINK32/TLIB/MAKE run natively on
  Win11; CODE/BT/OPT.MAK is the shipped BTL4OPT.EXE's exact flag recipe
  (extender = Borland PowerPack DPMI32, not Phar Lap TNT).
- restoration/source410/: the literal 1995-form reconstruction of the missing
  BT game source (never mixed into CODE/). Round 1-3 state:
  * 6 of 10 surviving original TUs COMPILE CLEAN under the period toolchain
    (BTMSSN, BTCNSL, BTSCNRL, BTTEAM, BTL4MODE, BTL4ARND) - first builds
    since 1996.
  * BT_L4/BTL4APP.CPP pilot reconstruction: 12/12 functions, Fail() lands on
    its binary-recorded line 400 exactly.
  * BT/BTCNSL.HPP: console wire IDs recovered from the binary's ctors
    (Killed=9, Damaged=10, ScoreUpdate=13, DeathWithoutHonor=15 [T1];
    TeamScore=12 flagged [T4]).
  * MUNGA/: 8 engine-header backfills back-dated from the BT412 WinTesla tree
    (VDATA numbering decomp-verified; AUDREND's OpenAL-era virtual removed -
    the period compiler is the drift detector).
  * Tooling: backdate.py (WinTesla->1995 header transform), compile410.sh
    (per-TU verification sweep under authentic OPT.MAK flags).
  * README: corrected roadmap - MECH.HPP is the capstone grown with the mech
    TU reconstructions; BTREG.CPP green = the header-family milestone.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-19 07:33:26 -05:00

75 lines
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/*------------------------------------------------------------------------
* filename - frexpl.cas
*
* function(s)
* frexpl - splits a long double number into mantissa and exponent
*-----------------------------------------------------------------------*/
/*
* C/C++ Run Time Library - Version 6.5
*
* Copyright (c) 1987, 1994 by Borland International
* All Rights Reserved.
*
*/
#pragma inline
#include <asmrules.h>
#include <_math.h>
#include <math.h>
/*--------------------------------------------------------------------------*
Name frexpl - splits a long double number into mantissa and exponent
Usage long double frexpl(long double value, int *expP);
Prototype in math.h
Description Split a floating point number into its exponent and
fractional parts, with the exponent placed into *expP, and
the fraction is the function return value.
Return value frexpl returns value - (*expP = chop (value));
*---------------------------------------------------------------------------*/
long double _FARFUNC frexpl (long double value, int *expP)
{
volatile unsigned statword;
asm FLD LONGDOUBLE (value)
asm LES_ bx, expP
asm mov W0 (ES_ [bx]), 0
/* if value was +-0, return it */
asm FTST
asm FSTSW statword
asm FWAIT
asm mov ah, BY1(statword)
asm sahf
asm jz done
asm FXTRACT /* ST(1) = exponent, (pushed) ST = fraction */
asm FXCH
/*
The FXTRACT instruction normalizes the fraction 1 bit higher than
wanted for the definition of frexpl() so we need to tweak the result
by scaling the fraction down and incrementing the exponent.
*/
asm FISTP W0 (ES_ [bx])
asm FLD1
asm FCHS
asm FXCH
asm FSCALE /* fraction scaled as C expects */
asm inc W0 (ES_ [bx]) /* exponent biased to match */
asm FSTP ST(1) /* discard -1, leave fraction as TOS */
done:
#pragma noretval
return;
}