blob: 592da65e75bc57fa3b4a7c90ca6a6339b0fc0f81 [file] [log] [blame]
# Copyright 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 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);
}
}
"""