kc3-lang/angle/src/libGLESv2/Float16ToFloat32.py

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• Hash : bef72cee
  Author :
  Date : 2012-10-23T20:36:33
  

  Fix Float16ToFloat32.py. Issue #376.
  Review URL: https://codereview.appspot.com/6651047
  
  git-svn-id: https://angleproject.googlecode.com/svn/trunk@1320 736b8ea6-26fd-11df-bfd4-992fa37f6226
  

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• src/libGLESv2/Float16ToFloat32.py

• # Copyright (c) 2012 The ANGLE Project Authors. All rights reserved.
  # Use of this source code is governed by a BSD-style license that can be
  # found in the LICENSE file.
  #
  
  # This script generates a function that converts 16-bit precision floating
  # point numbers to 32-bit.
  # It is based on ftp://ftp.fox-toolkit.org/pub/fasthalffloatconversion.pdf.
  
  def convertMantissa(i):
      if i == 0:
          return 0
      elif i < 1024:
          m = i << 13
          e = 0
          while not (m & 0x00800000):
              e -= 0x00800000
              m = m << 1
          m &= ~0x00800000
          e += 0x38800000
          return m | e
      else:
          return 0x38000000 + ((i - 1024) << 13)
  
  def convertExponent(i):
      if i == 0:
          return 0
      elif i in range(1, 31):
          return i << 23
      elif i == 31:
          return 0x47800000
      elif i == 32:
          return 0x80000000
      elif i in range(33, 63):
          return 0x80000000 + ((i - 32) << 23)
      else:
          return 0xC7800000
  
  def convertOffset(i):
      if i == 0 or i == 32:
          return 0
      else:
          return 1024
  
  print """//
  // Copyright (c) 2012 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  // This file is automatically generated.
  
  namespace gl
  {
  """
  
  print "const static unsigned g_mantissa[2048] = {"
  for i in range(0, 2048):
      print "    %#010x," % convertMantissa(i)
  print "};\n"
  
  print "const static unsigned g_exponent[64] = {"
  for i in range(0, 64):
      print "    %#010x," % convertExponent(i)
  print "};\n"
  
  print "const static unsigned g_offset[64] = {"
  for i in range(0, 64):
      print "    %#010x," % convertOffset(i)
  print "};\n"
  
  print """float float16ToFloat32(unsigned short h)
  {
      unsigned i32 = g_mantissa[g_offset[h >> 10] + (h & 0x3ff)] + g_exponent[h >> 10];
      return *(float*) &i32;
  }
  }
  """
  

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