src/lj_vmmath.c

   1 /*
   2 ** Math helper functions for assembler VM.
   3 ** Copyright (C) 2005-2011 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #define lj_vmmath_c
   7 #define LUA_CORE
   8
   9 #include <errno.h>
  10 #include <math.h>
  11
  12 #include "lj_obj.h"
  13 #if LJ_HASJIT
  14 #include "lj_ir.h"
  15 #endif
  16 #include "lj_vm.h"
  17
  18 /* -- Helper functions for generated machine code ------------------------- */
  19
  20 #if LJ_TARGET_X86ORX64
  21 /* Wrapper functions to avoid linker issues on OSX. */
  22 LJ_FUNCA double lj_vm_sinh(double x) { return sinh(x); }
  23 LJ_FUNCA double lj_vm_cosh(double x) { return cosh(x); }
  24 LJ_FUNCA double lj_vm_tanh(double x) { return tanh(x); }
  25 #endif
  26
  27 #if LJ_HASJIT
  28
  29 #ifdef LUAJIT_NO_LOG2
  30 double lj_vm_log2(double a)
  31 {
  32   return log(a) * 1.4426950408889634074;
  33 }
  34 #endif
  35
  36 #ifdef LUAJIT_NO_EXP2
  37 double lj_vm_exp2(double a)
  38 {
  39   return exp(a * 0.6931471805599453);
  40 }
  41 #endif
  42
  43 #if !(LJ_TARGET_ARM || LJ_TARGET_PPC)
  44 int32_t LJ_FASTCALL lj_vm_modi(int32_t a, int32_t b)
  45 {
  46   uint32_t y, ua, ub;
  47   lua_assert(b != 0);  /* This must be checked before using this function. */
  48   ua = a < 0 ? (uint32_t)-a : (uint32_t)a;
  49   ub = b < 0 ? (uint32_t)-b : (uint32_t)b;
  50   y = ua % ub;
  51   if (y != 0 && (a^b) < 0) y = y - ub;
  52   if (((int32_t)y^b) < 0) y = (uint32_t)-(int32_t)y;
  53   return (int32_t)y;
  54 }
  55 #endif
  56
  57 #if !LJ_TARGET_X86ORX64
  58 /* Unsigned x^k. */
  59 static double lj_vm_powui(double x, uint32_t k)
  60 {
  61   double y;
  62   lua_assert(k != 0);
  63   for (; (k & 1) == 0; k >>= 1) x *= x;
  64   y = x;
  65   if ((k >>= 1) != 0) {
  66     for (;;) {
  67       x *= x;
  68       if (k == 1) break;
  69       if (k & 1) y *= x;
  70       k >>= 1;
  71     }
  72     y *= x;
  73   }
  74   return y;
  75 }
  76
  77 /* Signed x^k. */
  78 double lj_vm_powi(double x, int32_t k)
  79 {
  80   if (k > 1)
  81     return lj_vm_powui(x, (uint32_t)k);
  82   else if (k == 1)
  83     return x;
  84   else if (k == 0)
  85     return 1.0;
  86   else
  87     return 1.0 / lj_vm_powui(x, (uint32_t)-k);
  88 }
  89
  90 /* Computes fpm(x) for extended math functions. */
  91 double lj_vm_foldfpm(double x, int fpm)
  92 {
  93   switch (fpm) {
  94   case IRFPM_FLOOR: return lj_vm_floor(x);
  95   case IRFPM_CEIL: return lj_vm_ceil(x);
  96   case IRFPM_TRUNC: return lj_vm_trunc(x);
  97   case IRFPM_SQRT: return sqrt(x);
  98   case IRFPM_EXP: return exp(x);
  99   case IRFPM_EXP2: return lj_vm_exp2(x);
 100   case IRFPM_LOG: return log(x);
 101   case IRFPM_LOG2: return lj_vm_log2(x);
 102   case IRFPM_LOG10: return log10(x);
 103   case IRFPM_SIN: return sin(x);
 104   case IRFPM_COS: return cos(x);
 105   case IRFPM_TAN: return tan(x);
 106   default: lua_assert(0);
 107   }
 108   return 0;
 109 }
 110 #endif
 111
 112 #if LJ_HASFFI
 113 int lj_vm_errno(void)
 114 {
 115   return errno;
 116 }
 117 #endif
 118
 119 #endif