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util: First stab at half-float conversion.

This commit is contained in:
Michal Krol 2010-03-31 21:54:54 +02:00
parent 329814c6ee
commit b8012643e1
1 changed files with 55 additions and 46 deletions
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101
src/gallium/auxiliary/util/u_format_pack.py
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@ -43,6 +43,45 @@ import math
from u_format_parse import *
def generate_f16_to_f32():
'''Naive implementation, need something faster that operates on bits'''
print '''
static float
f16_to_f32(uint16_t h)
{
unsigned mantissa = h & 0x3ff;
unsigned exponent = (h >> 10) & 0x1f;
float sign = (h & 0x8000) ? -1.0f : 1.0f;
if (exponent == 0) {
if (mantissa == 0) {
return sign * 0.0f;
}
return sign * powf(2.0f, -14.0f) * (float)mantissa / 1024.0f;
}
if (exponent == 31) {
if (mantissa == 0) {
/* XXX: infinity */
return sign * 100000.0f;
}
/* XXX: NaN */
return 1000.0f;
}
return sign * powf(2.0f, (float)exponent - 15.0f) * (1.0f + (float)mantissa / 1024.0f);
}
'''
def generate_f32_to_f16():
print '''
static uint16_t
f32_to_f16(float f)
{
/* TODO */
return 0;
}
'''
def generate_format_type(format):
'''Generate a structure that describes the format.'''
@ -127,9 +166,6 @@ def is_format_supported(format):
channel = format.channels[i]
if channel.type not in (VOID, UNSIGNED, SIGNED, FLOAT):
return False
if channel.type == FLOAT:
if channel.size not in (32, 64):
return False
# We can only read a color from a depth/stencil format if the depth channel is present
if format.colorspace == 'zs' and format.swizzles[0] == SWIZZLE_NONE:
@ -153,7 +189,9 @@ def native_type(format):
elif channel.type == SIGNED:
return 'int%u_t' % channel.size
elif channel.type == FLOAT:
if channel.size == 32:
if channel.size == 16:
return 'uint16_t'
elif channel.size == 32:
return 'float'
elif channel.size == 64:
return 'double'
@ -202,31 +240,6 @@ def get_one(type):
return (1 << get_one_shift(type)) - 1
def generate_clamp():
'''Code generate the clamping functions for each type.
We don't use a macro so that arguments with side effects,
like *src_pixel++ are correctly handled.
'''
for suffix, native_type in [
('', 'double'),
('f', 'float'),
('ui', 'unsigned int'),
('si', 'int'),
]:
print 'static INLINE %s' % native_type
print 'clamp%s(%s value, %s lbound, %s ubound)' % (suffix, native_type, native_type, native_type)
print '{'
print ' if(value < lbound)'
print ' return lbound;'
print ' if(value > ubound)'
print ' return ubound;'
print ' return value;'
print '}'
print
def clamp_expr(src_channel, dst_channel, dst_native_type, value):
'''Generate the expression to clamp the value in the source type to the
destination type range.'''
@ -234,21 +247,6 @@ def clamp_expr(src_channel, dst_channel, dst_native_type, value):
if src_channel == dst_channel:
return value
# Pick the approriate clamp function
if src_channel.type == FLOAT:
if src_channel.size == 32:
func = 'clampf'
elif src_channel.size == 64:
func = 'clamp'
else:
assert False
elif src_channel.type == UNSIGNED:
func = 'clampui'
elif src_channel.type == SIGNED:
func = 'clampsi'
else:
assert False
src_min = src_channel.min()
src_max = src_channel.max()
dst_min = dst_channel.min()
@ -273,7 +271,17 @@ def conversion_expr(src_channel, dst_channel, dst_native_type, value, clamp=True
return value
if src_channel.type == FLOAT and dst_channel.type == FLOAT:
return '(%s)%s' % (dst_native_type, value)
if src_channel.size == dst_channel.size:
return value
if src_channel.size == 64:
value = '(float)%s' % (value)
elif src_channel.size == 16:
value = 'f16_to_f32(%s)' % (value)
if dst_channel.size == 16:
value = 'f32_to_f16(%s)' % (value)
elif dst_channel.size == 64:
value = '(double)%s' % (value)
return value
if clamp:
value = clamp_expr(src_channel, dst_channel, dst_native_type, value)
@ -562,7 +570,8 @@ def generate(formats):
print '#include "u_format.h"'
print
generate_clamp()
generate_f16_to_f32()
generate_f32_to_f16()
for format in formats:
if is_format_supported(format):