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7d4a5898ac
That only leaves the Scale function which is still being used in a few places and which would create considerably worse code without assembly on 32 bit platforms. This is also far too primitive (2 or 3 assembly instructions) to claim any copyright on it, so I think m_fixed.h can now be considered free of Build-related issues. The deficated inline headers have been removed because that sole remaining function could be easily moved into m_fixed.h.
128 lines
4 KiB
C
128 lines
4 KiB
C
#ifndef __M_FIXED__
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#define __M_FIXED__
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#include <stdlib.h>
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#include "doomtype.h"
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// Unfortunately, the Scale function still gets badly handled on 32 bit x86 platforms so it's the last remaining piece of inline assembly
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// GCC inlines
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#if defined(__GNUC__) && defined(__i386__) && !defined(__clang__)
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#ifndef alloca
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// MinGW does not seem to come with alloca defined.
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#define alloca __builtin_alloca
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#endif
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static inline int32_t Scale(int32_t a, int32_t b, int32_t c)
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{
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int32_t result, dummy;
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asm volatile
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("imull %3\n\t"
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"idivl %4"
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: "=a,a,a,a,a,a" (result),
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"=&d,&d,&d,&d,d,d" (dummy)
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: "a,a,a,a,a,a" (a),
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"m,r,m,r,d,d" (b),
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"r,r,m,m,r,m" (c)
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: "cc"
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);
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return result;
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}
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// MSVC inlines
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#elif defined(_MSC_VER) && defined(_M_IX86)
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#pragma warning (disable: 4035)
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__forceinline int32_t Scale(int32_t a, int32_t b, int32_t c)
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{
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__asm mov eax, a
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__asm imul b
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__asm idiv c
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}
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#pragma warning (default: 4035)
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#else
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static __forceinline int32_t Scale(int32_t a, int32_t b, int32_t c)
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{
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return (int32_t)(((int64_t)a*b) / c);
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}
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#endif
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// Modern compilers are smart enough to do these multiplications intelligently.
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__forceinline int32_t MulScale14(int32_t a, int32_t b) { return (int32_t)(((int64_t)a * b) >> 14); } // only used by R_DrawVoxel
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__forceinline int32_t MulScale30(int32_t a, int32_t b) { return (int32_t)(((int64_t)a * b) >> 30); } // only used once in the node builder
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__forceinline int32_t MulScale32(int32_t a, int32_t b) { return (int32_t)(((int64_t)a * b) >> 32); } // only used by R_DrawVoxel
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__forceinline uint32_t UMulScale16(uint32_t a, uint32_t b) { return (uint32_t)(((uint64_t)a * b) >> 16); } // used for sky drawing
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__forceinline int32_t DMulScale3(int32_t a, int32_t b, int32_t c, int32_t d) { return (int32_t)(((int64_t)a*b + (int64_t)c*d) >> 3); } // used for setting up slopes for Build maps
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__forceinline int32_t DMulScale6(int32_t a, int32_t b, int32_t c, int32_t d) { return (int32_t)(((int64_t)a*b + (int64_t)c*d) >> 6); } // only used by R_DrawVoxel
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__forceinline int32_t DMulScale10(int32_t a, int32_t b, int32_t c, int32_t d) { return (int32_t)(((int64_t)a*b + (int64_t)c*d) >> 10); } // only used by R_DrawVoxel
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__forceinline int32_t DMulScale18(int32_t a, int32_t b, int32_t c, int32_t d) { return (int32_t)(((int64_t)a*b + (int64_t)c*d) >> 18); } // only used by R_DrawVoxel
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__forceinline int32_t DMulScale32(int32_t a, int32_t b, int32_t c, int32_t d) { return (int32_t)(((int64_t)a*b + (int64_t)c*d) >> 32); } // used by R_PointOnSide.
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// Sadly, for divisions this is not true but these are so infrequently used that the C versions are just fine, despite not being fully optimal.
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__forceinline int32_t DivScale6(int32_t a, int32_t b) { return (int32_t)(((int64_t)a << 6) / b); } // only used by R_DrawVoxel
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__forceinline int32_t DivScale21(int32_t a, int32_t b) { return (int32_t)(((int64_t)a << 21) / b); } // only used by R_DrawVoxel
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__forceinline int32_t DivScale30(int32_t a, int32_t b) { return (int32_t)(((int64_t)a << 30) / b); } // only used once in the node builder
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__forceinline void fillshort(void *buff, unsigned int count, WORD clear)
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{
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SWORD *b2 = (SWORD *)buff;
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for (unsigned int i = 0; i != count; ++i)
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{
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b2[i] = clear;
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}
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}
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#include "xs_Float.h"
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inline int32_t FixedDiv (int32_t a, int32_t b)
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{
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if ((uint32_t)abs(a) >> (31-16) >= (uint32_t)abs (b))
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return (a^b)<0 ? FIXED_MIN : FIXED_MAX;
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return (int32_t)(((int64_t)a << 16) / b);
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}
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__forceinline int32_t FixedMul(int32_t a, int32_t b)
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{
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return (int32_t)(((int64_t)a * b) >> 16);
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}
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inline fixed_t FloatToFixed(double f)
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{
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return xs_Fix<16>::ToFix(f);
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}
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inline double FixedToFloat(fixed_t f)
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{
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return f / 65536.;
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}
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inline unsigned FloatToAngle(double f)
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{
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return xs_CRoundToInt((f)* (0x40000000 / 90.));
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}
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inline double AngleToFloat(unsigned f)
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{
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return f * (90. / 0x40000000);
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}
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inline double AngleToFloat(int f)
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{
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return f * (90. / 0x40000000);
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}
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#define FLOAT2FIXED(f) FloatToFixed(f)
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#define FIXED2FLOAT(f) float(FixedToFloat(f))
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#define FIXED2DBL(f) FixedToFloat(f)
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#define ANGLE2DBL(f) AngleToFloat(f)
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#endif
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