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63 lines
1.3 KiB
C
63 lines
1.3 KiB
C
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS System Libraries
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* FILE: win32ss/gdi/gdi32/objects/efloat.c
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* PURPOSE: Functions to convert between FLOAT and EFLOAT
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* PROGRAMMER: James Tabor
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*/
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#include <precomp.h>
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/* the following deal with IEEE single-precision numbers */
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#define EXCESS 126L
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#define SIGNBIT 0x80000000L
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#define SIGN(fp) ((fp) & SIGNBIT)
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#define EXP(fp) (((fp) >> 23L) & 0xFF)
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#define MANT(fp) ((fp) & 0x7FFFFFL)
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#define PACK(s,e,m) ((s) | ((e) << 23L) | (m))
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FLOATL
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FASTCALL
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EFtoF(EFLOAT_S * efp)
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{
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ULONG Mant, Exp, Sign;
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if (!efp->lMant) return 0;
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Mant = efp->lMant;
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Exp = efp->lExp;
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Sign = SIGN(Mant);
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if (Sign) Mant = -(LONG)Mant;
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Mant >>= 7;
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Exp += (EXCESS-1);
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Mant = MANT(Mant);
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return PACK(Sign, Exp, Mant);
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}
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VOID
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FASTCALL
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FtoEF( EFLOAT_S * efp, FLOATL f)
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{
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ULONG Mant, Exp, Sign = 0;
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gxf_long worker;
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#ifdef _X86_
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worker.l = f; // It's a float stored in a long.
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#else
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worker.f = f;
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#endif
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Exp = EXP(worker.l);
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Mant = MANT(worker.l);
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if (SIGN(worker.l)) Sign = -1;
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Mant = ((Mant << 7) | 0x40000000);
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Mant ^= Sign;
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Mant -= Sign;
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Exp -= (EXCESS-1);
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efp->lMant = Mant;
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efp->lExp = Exp;
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}
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