glsl: move half<->float convertion to util
Needed in NIR too, so move out of mesa/main/imports.c Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> Reviewed-by: Emil Velikov <emil.velikov@collabora.com> Signed-off-by: Rob Clark <robclark@freedesktop.org>
This commit is contained in:
@@ -160,6 +160,7 @@ glsl_compiler_SOURCES = \
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glsl_compiler_LDADD = \
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libglsl.la \
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$(top_builddir)/src/libglsl_util.la \
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$(top_builddir)/src/util/libmesautil.la \
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$(PTHREAD_LIBS)
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glsl_test_SOURCES = \
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@@ -36,6 +36,7 @@
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#include <math.h>
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#include "main/core.h" /* for MAX2, MIN2, CLAMP */
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#include "util/rounding.h" /* for _mesa_roundeven */
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#include "util/half_float.h"
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#include "ir.h"
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#include "glsl_types.h"
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#include "program/hash_table.h"
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@@ -29,6 +29,7 @@ template = """\
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#include <math.h>
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#include "main/core.h"
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#include "util/rounding.h" /* for _mesa_roundeven */
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#include "util/half_float.h"
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#include "nir_constant_expressions.h"
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#if defined(__SUNPRO_CC)
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@@ -44,6 +44,7 @@
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#include "main/macros.h"
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#include "main/samplerobj.h"
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#include "util/half_float.h"
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/**
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* Emit a 3DSTATE_SAMPLER_STATE_POINTERS_{VS,HS,GS,DS,PS} packet.
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@@ -34,6 +34,7 @@
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#include "imports.h"
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#include "macros.h"
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#include "util/rounding.h"
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#include "util/half_float.h"
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extern const mesa_array_format RGBA32_FLOAT;
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extern const mesa_array_format RGBA8_UBYTE;
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@@ -307,154 +307,6 @@ _mesa_bitcount_64(uint64_t n)
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}
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#endif
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/**
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* Convert a 4-byte float to a 2-byte half float.
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*
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* Not all float32 values can be represented exactly as a float16 value. We
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* round such intermediate float32 values to the nearest float16. When the
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* float32 lies exactly between to float16 values, we round to the one with
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* an even mantissa.
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*
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* This rounding behavior has several benefits:
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* - It has no sign bias.
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*
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* - It reproduces the behavior of real hardware: opcode F32TO16 in Intel's
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* GPU ISA.
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*
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* - By reproducing the behavior of the GPU (at least on Intel hardware),
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* compile-time evaluation of constant packHalf2x16 GLSL expressions will
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* result in the same value as if the expression were executed on the GPU.
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*/
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GLhalfARB
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_mesa_float_to_half(float val)
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{
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const fi_type fi = {val};
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const int flt_m = fi.i & 0x7fffff;
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const int flt_e = (fi.i >> 23) & 0xff;
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const int flt_s = (fi.i >> 31) & 0x1;
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int s, e, m = 0;
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GLhalfARB result;
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/* sign bit */
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s = flt_s;
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/* handle special cases */
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if ((flt_e == 0) && (flt_m == 0)) {
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/* zero */
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/* m = 0; - already set */
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e = 0;
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}
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else if ((flt_e == 0) && (flt_m != 0)) {
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/* denorm -- denorm float maps to 0 half */
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/* m = 0; - already set */
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e = 0;
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}
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else if ((flt_e == 0xff) && (flt_m == 0)) {
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/* infinity */
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/* m = 0; - already set */
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e = 31;
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}
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else if ((flt_e == 0xff) && (flt_m != 0)) {
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/* NaN */
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m = 1;
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e = 31;
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}
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else {
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/* regular number */
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const int new_exp = flt_e - 127;
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if (new_exp < -14) {
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/* The float32 lies in the range (0.0, min_normal16) and is rounded
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* to a nearby float16 value. The result will be either zero, subnormal,
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* or normal.
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*/
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e = 0;
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m = _mesa_lroundevenf((1 << 24) * fabsf(fi.f));
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}
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else if (new_exp > 15) {
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/* map this value to infinity */
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/* m = 0; - already set */
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e = 31;
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}
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else {
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/* The float32 lies in the range
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* [min_normal16, max_normal16 + max_step16)
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* and is rounded to a nearby float16 value. The result will be
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* either normal or infinite.
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*/
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e = new_exp + 15;
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m = _mesa_lroundevenf(flt_m / (float) (1 << 13));
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}
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}
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assert(0 <= m && m <= 1024);
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if (m == 1024) {
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/* The float32 was rounded upwards into the range of the next exponent,
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* so bump the exponent. This correctly handles the case where f32
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* should be rounded up to float16 infinity.
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*/
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++e;
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m = 0;
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}
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result = (s << 15) | (e << 10) | m;
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return result;
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}
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/**
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* Convert a 2-byte half float to a 4-byte float.
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* Based on code from:
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* http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
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*/
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float
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_mesa_half_to_float(GLhalfARB val)
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{
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/* XXX could also use a 64K-entry lookup table */
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const int m = val & 0x3ff;
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const int e = (val >> 10) & 0x1f;
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const int s = (val >> 15) & 0x1;
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int flt_m, flt_e, flt_s;
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fi_type fi;
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float result;
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/* sign bit */
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flt_s = s;
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/* handle special cases */
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if ((e == 0) && (m == 0)) {
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/* zero */
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flt_m = 0;
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flt_e = 0;
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}
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else if ((e == 0) && (m != 0)) {
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/* denorm -- denorm half will fit in non-denorm single */
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const float half_denorm = 1.0f / 16384.0f; /* 2^-14 */
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float mantissa = ((float) (m)) / 1024.0f;
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float sign = s ? -1.0f : 1.0f;
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return sign * mantissa * half_denorm;
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}
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else if ((e == 31) && (m == 0)) {
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/* infinity */
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flt_e = 0xff;
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flt_m = 0;
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}
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else if ((e == 31) && (m != 0)) {
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/* NaN */
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flt_e = 0xff;
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flt_m = 1;
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}
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else {
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/* regular */
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flt_e = e + 112;
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flt_m = m << 13;
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}
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fi.i = (flt_s << 31) | (flt_e << 23) | flt_m;
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result = fi.f;
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return result;
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}
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/*@}*/
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@@ -396,13 +396,6 @@ _mesa_flsll(uint64_t n)
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#endif
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}
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extern GLhalfARB
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_mesa_float_to_half(float f);
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extern float
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_mesa_half_to_float(GLhalfARB h);
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static inline bool
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_mesa_half_is_negative(GLhalfARB h)
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{
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@@ -37,6 +37,7 @@
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#include "texstore.h"
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#include "image.h"
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#include "macros.h"
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#include "util/half_float.h"
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#include "../../gallium/auxiliary/util/u_format_rgb9e5.h"
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#include "../../gallium/auxiliary/util/u_format_r11g11b10f.h"
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@@ -30,6 +30,7 @@
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#include "texcompress.h"
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#include "texcompress_bptc.h"
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#include "util/format_srgb.h"
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#include "util/half_float.h"
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#include "texstore.h"
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#include "macros.h"
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#include "image.h"
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@@ -35,6 +35,7 @@
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#include "main/mtypes.h"
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#include "main/macros.h"
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#include "main/enums.h"
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#include "util/half_float.h"
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#include "t_context.h"
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#include "tnl.h"
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@@ -3,6 +3,8 @@ MESA_UTIL_FILES := \
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debug.c \
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debug.h \
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format_srgb.h \
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half_float.c \
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half_float.h \
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hash_table.c \
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hash_table.h \
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list.h \
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177
src/util/half_float.c
Normal file
177
src/util/half_float.c
Normal file
@@ -0,0 +1,177 @@
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/*
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* Mesa 3-D graphics library
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*
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* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <math.h>
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#include <assert.h>
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#include "half_float.h"
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#include "rounding.h"
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typedef union { float f; int32_t i; uint32_t u; } fi_type;
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/**
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* Convert a 4-byte float to a 2-byte half float.
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*
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* Not all float32 values can be represented exactly as a float16 value. We
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* round such intermediate float32 values to the nearest float16. When the
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* float32 lies exactly between to float16 values, we round to the one with
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* an even mantissa.
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*
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* This rounding behavior has several benefits:
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* - It has no sign bias.
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*
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* - It reproduces the behavior of real hardware: opcode F32TO16 in Intel's
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* GPU ISA.
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*
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* - By reproducing the behavior of the GPU (at least on Intel hardware),
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* compile-time evaluation of constant packHalf2x16 GLSL expressions will
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* result in the same value as if the expression were executed on the GPU.
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*/
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uint16_t
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_mesa_float_to_half(float val)
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{
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const fi_type fi = {val};
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const int flt_m = fi.i & 0x7fffff;
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const int flt_e = (fi.i >> 23) & 0xff;
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const int flt_s = (fi.i >> 31) & 0x1;
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int s, e, m = 0;
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uint16_t result;
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/* sign bit */
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s = flt_s;
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/* handle special cases */
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if ((flt_e == 0) && (flt_m == 0)) {
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/* zero */
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/* m = 0; - already set */
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e = 0;
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}
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else if ((flt_e == 0) && (flt_m != 0)) {
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/* denorm -- denorm float maps to 0 half */
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/* m = 0; - already set */
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e = 0;
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}
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else if ((flt_e == 0xff) && (flt_m == 0)) {
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/* infinity */
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/* m = 0; - already set */
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e = 31;
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}
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else if ((flt_e == 0xff) && (flt_m != 0)) {
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/* NaN */
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m = 1;
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e = 31;
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}
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else {
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/* regular number */
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const int new_exp = flt_e - 127;
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if (new_exp < -14) {
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/* The float32 lies in the range (0.0, min_normal16) and is rounded
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* to a nearby float16 value. The result will be either zero, subnormal,
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* or normal.
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*/
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e = 0;
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m = _mesa_lroundevenf((1 << 24) * fabsf(fi.f));
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}
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else if (new_exp > 15) {
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/* map this value to infinity */
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/* m = 0; - already set */
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e = 31;
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}
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else {
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/* The float32 lies in the range
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* [min_normal16, max_normal16 + max_step16)
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* and is rounded to a nearby float16 value. The result will be
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* either normal or infinite.
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*/
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e = new_exp + 15;
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m = _mesa_lroundevenf(flt_m / (float) (1 << 13));
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}
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}
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assert(0 <= m && m <= 1024);
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if (m == 1024) {
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/* The float32 was rounded upwards into the range of the next exponent,
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* so bump the exponent. This correctly handles the case where f32
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* should be rounded up to float16 infinity.
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*/
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++e;
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m = 0;
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}
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result = (s << 15) | (e << 10) | m;
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return result;
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}
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/**
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* Convert a 2-byte half float to a 4-byte float.
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* Based on code from:
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* http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
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*/
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float
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_mesa_half_to_float(uint16_t val)
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{
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/* XXX could also use a 64K-entry lookup table */
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const int m = val & 0x3ff;
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const int e = (val >> 10) & 0x1f;
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const int s = (val >> 15) & 0x1;
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int flt_m, flt_e, flt_s;
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fi_type fi;
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float result;
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/* sign bit */
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flt_s = s;
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/* handle special cases */
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if ((e == 0) && (m == 0)) {
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/* zero */
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flt_m = 0;
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flt_e = 0;
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}
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else if ((e == 0) && (m != 0)) {
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/* denorm -- denorm half will fit in non-denorm single */
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const float half_denorm = 1.0f / 16384.0f; /* 2^-14 */
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float mantissa = ((float) (m)) / 1024.0f;
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float sign = s ? -1.0f : 1.0f;
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return sign * mantissa * half_denorm;
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}
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else if ((e == 31) && (m == 0)) {
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/* infinity */
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flt_e = 0xff;
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flt_m = 0;
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}
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else if ((e == 31) && (m != 0)) {
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/* NaN */
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flt_e = 0xff;
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flt_m = 1;
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}
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else {
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/* regular */
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flt_e = e + 112;
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flt_m = m << 13;
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}
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fi.i = (flt_s << 31) | (flt_e << 23) | flt_m;
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result = fi.f;
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return result;
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}
|
41
src/util/half_float.h
Normal file
41
src/util/half_float.h
Normal file
@@ -0,0 +1,41 @@
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/*
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* Mesa 3-D graphics library
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*
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* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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*
|
||||
* Permission is hereby granted, free of charge, to any person obtaining a
|
||||
* copy of this software and associated documentation files (the "Software"),
|
||||
* to deal in the Software without restriction, including without limitation
|
||||
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
||||
* and/or sell copies of the Software, and to permit persons to whom the
|
||||
* Software is furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be included
|
||||
* in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
|
||||
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
||||
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
||||
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
|
||||
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
|
||||
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
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* OTHER DEALINGS IN THE SOFTWARE.
|
||||
*/
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#ifndef _HALF_FLOAT_H_
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#define _HALF_FLOAT_H_
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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uint16_t _mesa_float_to_half(float val);
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float _mesa_half_to_float(uint16_t val);
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#ifdef __cplusplus
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} /* extern C */
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#endif
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#endif /* _HALF_FLOAT_H_ */
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Block a user