src/lj_vmmath.c

   1 /*
   2 ** Math helper functions for assembler VM.
   3 ** Copyright (C) 2005-2012 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 || LJ_TARGET_MIPS
  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_TARGET_MIPS
  28 double lj_vm_foldarith(double x, double y, int op)
  29 {
  30   switch (op) {
  31   case IR_ADD - IR_ADD: return x+y; break;
  32   case IR_SUB - IR_ADD: return x-y; break;
  33   case IR_MUL - IR_ADD: return x*y; break;
  34   case IR_DIV - IR_ADD: return x/y; break;
  35   case IR_MOD - IR_ADD: return x-lj_vm_floor(x/y)*y; break;
  36   case IR_POW - IR_ADD: return pow(x, y); break;
  37   case IR_NEG - IR_ADD: return -x; break;
  38   case IR_ABS - IR_ADD: return fabs(x); break;
  39 #if LJ_HASJIT
  40   case IR_ATAN2 - IR_ADD: return atan2(x, y); break;
  41   case IR_LDEXP - IR_ADD: return ldexp(x, (int)y); break;
  42   case IR_MIN - IR_ADD: return x > y ? y : x; break;
  43   case IR_MAX - IR_ADD: return x < y ? y : x; break;
  44 #endif
  45   default: return x;
  46   }
  47 }
  48 #endif
  49
  50 #if LJ_HASJIT
  51
  52 #ifdef LUAJIT_NO_LOG2
  53 double lj_vm_log2(double a)
  54 {
  55   return log(a) * 1.4426950408889634074;
  56 }
  57 #endif
  58
  59 #ifdef LUAJIT_NO_EXP2
  60 double lj_vm_exp2(double a)
  61 {
  62   return exp(a * 0.6931471805599453);
  63 }
  64 #endif
  65
  66 #if !(LJ_TARGET_ARM || LJ_TARGET_PPC)
  67 int32_t LJ_FASTCALL lj_vm_modi(int32_t a, int32_t b)
  68 {
  69   uint32_t y, ua, ub;
  70   lua_assert(b != 0);  /* This must be checked before using this function. */
  71   ua = a < 0 ? (uint32_t)-a : (uint32_t)a;
  72   ub = b < 0 ? (uint32_t)-b : (uint32_t)b;
  73   y = ua % ub;
  74   if (y != 0 && (a^b) < 0) y = y - ub;
  75   if (((int32_t)y^b) < 0) y = (uint32_t)-(int32_t)y;
  76   return (int32_t)y;
  77 }
  78 #endif
  79
  80 #if !LJ_TARGET_X86ORX64
  81 /* Unsigned x^k. */
  82 static double lj_vm_powui(double x, uint32_t k)
  83 {
  84   double y;
  85   lua_assert(k != 0);
  86   for (; (k & 1) == 0; k >>= 1) x *= x;
  87   y = x;
  88   if ((k >>= 1) != 0) {
  89     for (;;) {
  90       x *= x;
  91       if (k == 1) break;
  92       if (k & 1) y *= x;
  93       k >>= 1;
  94     }
  95     y *= x;
  96   }
  97   return y;
  98 }
  99
 100 /* Signed x^k. */
 101 double lj_vm_powi(double x, int32_t k)
 102 {
 103   if (k > 1)
 104     return lj_vm_powui(x, (uint32_t)k);
 105   else if (k == 1)
 106     return x;
 107   else if (k == 0)
 108     return 1.0;
 109   else
 110     return 1.0 / lj_vm_powui(x, (uint32_t)-k);
 111 }
 112
 113 /* Computes fpm(x) for extended math functions. */
 114 double lj_vm_foldfpm(double x, int fpm)
 115 {
 116   switch (fpm) {
 117   case IRFPM_FLOOR: return lj_vm_floor(x);
 118   case IRFPM_CEIL: return lj_vm_ceil(x);
 119   case IRFPM_TRUNC: return lj_vm_trunc(x);
 120   case IRFPM_SQRT: return sqrt(x);
 121   case IRFPM_EXP: return exp(x);
 122   case IRFPM_EXP2: return lj_vm_exp2(x);
 123   case IRFPM_LOG: return log(x);
 124   case IRFPM_LOG2: return lj_vm_log2(x);
 125   case IRFPM_LOG10: return log10(x);
 126   case IRFPM_SIN: return sin(x);
 127   case IRFPM_COS: return cos(x);
 128   case IRFPM_TAN: return tan(x);
 129   default: lua_assert(0);
 130   }
 131   return 0;
 132 }
 133 #endif
 134
 135 #if LJ_HASFFI
 136 int lj_vm_errno(void)
 137 {
 138   return errno;
 139 }
 140 #endif
 141
 142 #endif