core/fpu_ctrl.cpp

   1
   2 #include "config.h"
   3
   4 #include "fpu_ctrl.h"
   5
   6 #ifdef HAVE_INTRIN_H
   7 #include <intrin.h>
   8 #endif
   9 #ifdef HAVE_SSE_INTRINSICS
  10 #include <emmintrin.h>
  11 #ifndef _MM_DENORMALS_ZERO_MASK
  12 /* Some headers seem to be missing these? */
  13 #define _MM_DENORMALS_ZERO_MASK 0x0040u
  14 #define _MM_DENORMALS_ZERO_ON 0x0040u
  15 #endif
  16 #endif
  17
  18 #include "cpu_caps.h"
  19
  20
  21 void FPUCtl::enter() noexcept
  22 {
  23     if(this->in_mode) return;
  24
  25 #if defined(HAVE_SSE_INTRINSICS)
  26     this->sse_state = _mm_getcsr();
  27     unsigned int sseState{this->sse_state};
  28     sseState &= ~(_MM_FLUSH_ZERO_MASK | _MM_DENORMALS_ZERO_MASK);
  29     sseState |= _MM_FLUSH_ZERO_ON | _MM_DENORMALS_ZERO_ON;
  30     _mm_setcsr(sseState);
  31
  32 #elif defined(__GNUC__) && defined(HAVE_SSE)
  33
  34     if((CPUCapFlags&CPU_CAP_SSE))
  35     {
  36         __asm__ __volatile__("stmxcsr %0" : "=m" (*&this->sse_state));
  37         unsigned int sseState{this->sse_state};
  38         sseState |= 0x8000; /* set flush-to-zero */
  39         if((CPUCapFlags&CPU_CAP_SSE2))
  40             sseState |= 0x0040; /* set denormals-are-zero */
  41         __asm__ __volatile__("ldmxcsr %0" : : "m" (*&sseState));
  42     }
  43 #endif
  44
  45     this->in_mode = true;
  46 }
  47
  48 void FPUCtl::leave() noexcept
  49 {
  50     if(!this->in_mode) return;
  51
  52 #if defined(HAVE_SSE_INTRINSICS)
  53     _mm_setcsr(this->sse_state);
  54
  55 #elif defined(__GNUC__) && defined(HAVE_SSE)
  56
  57     if((CPUCapFlags&CPU_CAP_SSE))
  58         __asm__ __volatile__("ldmxcsr %0" : : "m" (*&this->sse_state));
  59 #endif
  60     this->in_mode = false;
  61 }