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

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• Author : Geoff Lang
  Date : 2019-05-06 13:15:35
  Hash : d7d42395
  Message : Format all of ANGLE's python code. BUG=angleproject:3421 Change-Id: I1d7282ac513c046de5d8ed87f7789290780d30a6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1595440 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>

• src/common/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.
  
  #include "common/mathutil.h"
  
  
  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 bitCast<float>(i32);
  }
  }
  """