CydandClaude Fable 5
63312e07f9
- 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>
126 lines
3.2 KiB
Plaintext
126 lines
3.2 KiB
Plaintext
/*------------------------------------------------------------------------
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* filename - frexp.cas
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*
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* function(s)
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* frexp - splits a double number into mantissa and exponent
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*-----------------------------------------------------------------------*/
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/*
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* C/C++ Run Time Library - Version 6.5
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*
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* Copyright (c) 1987, 1994 by Borland International
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* All Rights Reserved.
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*
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*/
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#pragma inline
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#include <asmrules.h>
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#include <_math.h>
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#include <math.h>
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/*--------------------------------------------------------------------------*
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Name frexp - splits a double number into mantissa and exponent
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Usage double frexp(double value, int *expP);
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Prototype in math.h
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Description Split a floating point number into its exponent and
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fractional parts, with the exponent placed into *expP, and
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the fraction is the function return value.
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Return value frexp returns value - (*expP = chop (value));
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*---------------------------------------------------------------------------*/
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double _FARFUNC frexp( double value, int *expP )
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{
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volatile unsigned statword;
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#ifdef _Windows
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// The Microsoft FP emulator does not support the FXTRACT instruction.
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_CX = 0;
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start:
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asm {
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mov ax, value[6]
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mov dx, ax
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and ax, 7FF0h
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jz denormal
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sub dx, ax
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sub ax, 3FE0h
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or dx, 3FE0h
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mov value[6], dx
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FLD DOUBLE (value)
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sub ax, cx // possible denormal adjustment
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mov cl, 4
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sar ax, cl
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}
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done:
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*expP = _AX;
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#pragma noretval
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return;
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denormal:
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// denormal case a little tricky, so we normalize and try again
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asm {
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FLD DOUBLE (value)
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FTST
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FSTSW statword
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FWAIT
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mov ax, statword
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sahf
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xchg ax, cx // convenient 0
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jz done // result is +0 or -0
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mov W0 (statword), 100
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FILD W0 (statword)
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FXCH
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FSCALE
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FSTP DOUBLE(value)
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mov cx, 100 * 10h
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FSTP st(0) // discard 100
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}
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goto start;
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#else /* not Windows */
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asm FLD DOUBLE (value)
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asm LES_ bx, expP
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asm mov W0 (ES_ [bx]), 0
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/* if value was +-0, return it */
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asm FTST
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asm FSTSW statword
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asm FWAIT
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asm mov ah, BY1(statword)
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asm sahf
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asm jz done
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asm FXTRACT /* ST(1) = exponent, (pushed) ST = fraction */
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asm FXCH
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/*
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The FXTRACT instruction normalizes the fraction 1 bit higher than
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wanted for the definition of frexp() so we need to tweak the result
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by scaling the fraction down and incrementing the exponent.
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*/
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asm FISTP W0 (ES_ [bx])
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asm FLD1
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asm FCHS
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asm FXCH
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asm FSCALE /* fraction scaled as C expects */
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asm inc W0 (ES_ [bx]) /* exponent biased to match */
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asm FSTP ST(1) /* discard -1, leave fraction as TOS */
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done:
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#pragma noretval
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return;
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#endif /* Windows */
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}
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