77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
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/*
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** The contents of this file are subject to the Mozilla Public License
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** Version 1.1 (the "License"); you may not use this file except in compliance
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** with the License. You may obtain a copy of the License at
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** http://www.mozilla.org/MPL/
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**
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** Software distributed under the License is distributed on an "AS IS" basis,
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** WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
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** the specific language governing rights and limitations under the License.
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*/
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#ifndef __FIX_H__
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#define __FIX_H__
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/*
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** Fixed point maths.
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** Thanks to the KenBuild, Doom and Decent for some great ideas.
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*/
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#define FRACCEIL 0xFFFF
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#define f2i(a) ((a)>>16)
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#define i2f(a) ((a)<<16)
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#define f2fl(a) (((float)(a))/ i2f(1))
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#define fl2f(a) ((int)((a)*i2f(1)))
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#define fixceil(A) (((A)+0xFFFF)>>16)
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extern int sintable[2048];
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#define fixsin(A) sintable[(A)&2047]
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#define fixcos(A) sintable[((A)+512)&2047]
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int fixinv(int);
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int fixmul(int, int);
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int fixdiv(int, int);
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int fixdot3(int, int, int, int, int, int);
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#ifdef __WATCOMC__
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#pragma aux fixinv = \
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"xor eax, eax" \
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"mov edx, 1" \
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"idiv ebx" \
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parm caller [ebx] \
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value [eax] \
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modify [eax ebx edx];
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#pragma aux fixmul parm [eax] [edx] = \
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"imul edx" \
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"shrd eax,edx,16";
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#pragma aux fixdiv parm [eax] [ebx] modify exact [eax edx] = \
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"mov edx,eax" \
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"sar edx,16" \
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"shl eax,16" \
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"idiv ebx";
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#pragma aux fixdot3 =\
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"imul edx",\
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"xchg eax, ebx",\
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"xchg edx, ecx",\
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"imul edx",\
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"add ebx, eax",\
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"adc ecx, edx",\
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"mov eax, esi",\
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"imul edi",\
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"add eax, ebx",\
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"adc edx, ecx",\
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"shrd eax, edx, 16",\
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parm nomemory [eax][edx][ebx][ecx][esi][edi]\
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modify exact [eax ebx ecx edx];
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#endif
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#endif
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