[Mesa-dev] [PATCH 3/6] glsl: move half<->float convertion to util
Rob Clark
robdclark at gmail.com
Sat Oct 10 11:47:44 PDT 2015
From: Rob Clark <robclark at freedesktop.org>
Needed in NIR too, so move out of mesa/main/imports.c
Signed-off-by: Rob Clark <robclark at freedesktop.org>
---
src/glsl/Makefile.am | 1 +
src/mesa/main/imports.c | 148 --------------------------------------
src/mesa/main/imports.h | 38 ++++++++--
src/util/Makefile.sources | 2 +
src/util/convert.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++
src/util/convert.h | 43 +++++++++++
6 files changed, 259 insertions(+), 152 deletions(-)
create mode 100644 src/util/convert.c
create mode 100644 src/util/convert.h
diff --git a/src/glsl/Makefile.am b/src/glsl/Makefile.am
index 3265391..347919b 100644
--- a/src/glsl/Makefile.am
+++ b/src/glsl/Makefile.am
@@ -160,6 +160,7 @@ glsl_compiler_SOURCES = \
glsl_compiler_LDADD = \
libglsl.la \
$(top_builddir)/src/libglsl_util.la \
+ $(top_builddir)/src/util/libmesautil.la \
$(PTHREAD_LIBS)
glsl_test_SOURCES = \
diff --git a/src/mesa/main/imports.c b/src/mesa/main/imports.c
index 350e675..230ebbc 100644
--- a/src/mesa/main/imports.c
+++ b/src/mesa/main/imports.c
@@ -307,154 +307,6 @@ _mesa_bitcount_64(uint64_t n)
}
#endif
-
-/**
- * Convert a 4-byte float to a 2-byte half float.
- *
- * Not all float32 values can be represented exactly as a float16 value. We
- * round such intermediate float32 values to the nearest float16. When the
- * float32 lies exactly between to float16 values, we round to the one with
- * an even mantissa.
- *
- * This rounding behavior has several benefits:
- * - It has no sign bias.
- *
- * - It reproduces the behavior of real hardware: opcode F32TO16 in Intel's
- * GPU ISA.
- *
- * - By reproducing the behavior of the GPU (at least on Intel hardware),
- * compile-time evaluation of constant packHalf2x16 GLSL expressions will
- * result in the same value as if the expression were executed on the GPU.
- */
-GLhalfARB
-_mesa_float_to_half(float val)
-{
- const fi_type fi = {val};
- const int flt_m = fi.i & 0x7fffff;
- const int flt_e = (fi.i >> 23) & 0xff;
- const int flt_s = (fi.i >> 31) & 0x1;
- int s, e, m = 0;
- GLhalfARB result;
-
- /* sign bit */
- s = flt_s;
-
- /* handle special cases */
- if ((flt_e == 0) && (flt_m == 0)) {
- /* zero */
- /* m = 0; - already set */
- e = 0;
- }
- else if ((flt_e == 0) && (flt_m != 0)) {
- /* denorm -- denorm float maps to 0 half */
- /* m = 0; - already set */
- e = 0;
- }
- else if ((flt_e == 0xff) && (flt_m == 0)) {
- /* infinity */
- /* m = 0; - already set */
- e = 31;
- }
- else if ((flt_e == 0xff) && (flt_m != 0)) {
- /* NaN */
- m = 1;
- e = 31;
- }
- else {
- /* regular number */
- const int new_exp = flt_e - 127;
- if (new_exp < -14) {
- /* The float32 lies in the range (0.0, min_normal16) and is rounded
- * to a nearby float16 value. The result will be either zero, subnormal,
- * or normal.
- */
- e = 0;
- m = _mesa_lroundevenf((1 << 24) * fabsf(fi.f));
- }
- else if (new_exp > 15) {
- /* map this value to infinity */
- /* m = 0; - already set */
- e = 31;
- }
- else {
- /* The float32 lies in the range
- * [min_normal16, max_normal16 + max_step16)
- * and is rounded to a nearby float16 value. The result will be
- * either normal or infinite.
- */
- e = new_exp + 15;
- m = _mesa_lroundevenf(flt_m / (float) (1 << 13));
- }
- }
-
- assert(0 <= m && m <= 1024);
- if (m == 1024) {
- /* The float32 was rounded upwards into the range of the next exponent,
- * so bump the exponent. This correctly handles the case where f32
- * should be rounded up to float16 infinity.
- */
- ++e;
- m = 0;
- }
-
- result = (s << 15) | (e << 10) | m;
- return result;
-}
-
-
-/**
- * Convert a 2-byte half float to a 4-byte float.
- * Based on code from:
- * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
- */
-float
-_mesa_half_to_float(GLhalfARB val)
-{
- /* XXX could also use a 64K-entry lookup table */
- const int m = val & 0x3ff;
- const int e = (val >> 10) & 0x1f;
- const int s = (val >> 15) & 0x1;
- int flt_m, flt_e, flt_s;
- fi_type fi;
- float result;
-
- /* sign bit */
- flt_s = s;
-
- /* handle special cases */
- if ((e == 0) && (m == 0)) {
- /* zero */
- flt_m = 0;
- flt_e = 0;
- }
- else if ((e == 0) && (m != 0)) {
- /* denorm -- denorm half will fit in non-denorm single */
- const float half_denorm = 1.0f / 16384.0f; /* 2^-14 */
- float mantissa = ((float) (m)) / 1024.0f;
- float sign = s ? -1.0f : 1.0f;
- return sign * mantissa * half_denorm;
- }
- else if ((e == 31) && (m == 0)) {
- /* infinity */
- flt_e = 0xff;
- flt_m = 0;
- }
- else if ((e == 31) && (m != 0)) {
- /* NaN */
- flt_e = 0xff;
- flt_m = 1;
- }
- else {
- /* regular */
- flt_e = e + 112;
- flt_m = m << 13;
- }
-
- fi.i = (flt_s << 31) | (flt_e << 23) | flt_m;
- result = fi.f;
- return result;
-}
-
/*@}*/
diff --git a/src/mesa/main/imports.h b/src/mesa/main/imports.h
index 9024758..3a09304 100644
--- a/src/mesa/main/imports.h
+++ b/src/mesa/main/imports.h
@@ -42,6 +42,7 @@
#include "compiler.h"
#include "glheader.h"
#include "errors.h"
+#include "util/convert.h"
#ifdef __cplusplus
extern "C" {
@@ -396,12 +397,41 @@ _mesa_flsll(uint64_t n)
#endif
}
+/**
+ * Convert a 4-byte float to a 2-byte half float.
+ *
+ * Not all float32 values can be represented exactly as a float16 value. We
+ * round such intermediate float32 values to the nearest float16. When the
+ * float32 lies exactly between to float16 values, we round to the one with
+ * an even mantissa.
+ *
+ * This rounding behavior has several benefits:
+ * - It has no sign bias.
+ *
+ * - It reproduces the behavior of real hardware: opcode F32TO16 in Intel's
+ * GPU ISA.
+ *
+ * - By reproducing the behavior of the GPU (at least on Intel hardware),
+ * compile-time evaluation of constant packHalf2x16 GLSL expressions will
+ * result in the same value as if the expression were executed on the GPU.
+ */
+static inline GLhalfARB
+_mesa_float_to_half(float val)
+{
+ return float_to_half(val);
+}
-extern GLhalfARB
-_mesa_float_to_half(float f);
-extern float
-_mesa_half_to_float(GLhalfARB h);
+/**
+ * Convert a 2-byte half float to a 4-byte float.
+ * Based on code from:
+ * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
+ */
+static inline float
+_mesa_half_to_float(GLhalfARB val)
+{
+ return half_to_float(val);
+}
static inline bool
_mesa_half_is_negative(GLhalfARB h)
diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
index e45431d..71b2a25 100644
--- a/src/util/Makefile.sources
+++ b/src/util/Makefile.sources
@@ -1,5 +1,7 @@
MESA_UTIL_FILES := \
bitset.h \
+ convert.c \
+ convert.h \
debug.c \
debug.h \
format_srgb.h \
diff --git a/src/util/convert.c b/src/util/convert.c
new file mode 100644
index 0000000..e86e322
--- /dev/null
+++ b/src/util/convert.c
@@ -0,0 +1,179 @@
+/*
+ * Copyright © 2015 Red Hat
+ *
+ * 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 (including the next
+ * paragraph) 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 OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Rob Clark <robclark at freedesktop.org>
+ */
+
+#include <math.h>
+#include <assert.h>
+#include "convert.h"
+#include "rounding.h"
+
+typedef union { float f; int32_t i; uint32_t u; } fi_type;
+
+/**
+ * Convert a 4-byte float to a 2-byte half float.
+ *
+ * Not all float32 values can be represented exactly as a float16 value. We
+ * round such intermediate float32 values to the nearest float16. When the
+ * float32 lies exactly between to float16 values, we round to the one with
+ * an even mantissa.
+ *
+ * This rounding behavior has several benefits:
+ * - It has no sign bias.
+ *
+ * - It reproduces the behavior of real hardware: opcode F32TO16 in Intel's
+ * GPU ISA.
+ *
+ * - By reproducing the behavior of the GPU (at least on Intel hardware),
+ * compile-time evaluation of constant packHalf2x16 GLSL expressions will
+ * result in the same value as if the expression were executed on the GPU.
+ */
+uint16_t
+float_to_half(float val)
+{
+ const fi_type fi = {val};
+ const int flt_m = fi.i & 0x7fffff;
+ const int flt_e = (fi.i >> 23) & 0xff;
+ const int flt_s = (fi.i >> 31) & 0x1;
+ int s, e, m = 0;
+ uint16_t result;
+
+ /* sign bit */
+ s = flt_s;
+
+ /* handle special cases */
+ if ((flt_e == 0) && (flt_m == 0)) {
+ /* zero */
+ /* m = 0; - already set */
+ e = 0;
+ }
+ else if ((flt_e == 0) && (flt_m != 0)) {
+ /* denorm -- denorm float maps to 0 half */
+ /* m = 0; - already set */
+ e = 0;
+ }
+ else if ((flt_e == 0xff) && (flt_m == 0)) {
+ /* infinity */
+ /* m = 0; - already set */
+ e = 31;
+ }
+ else if ((flt_e == 0xff) && (flt_m != 0)) {
+ /* NaN */
+ m = 1;
+ e = 31;
+ }
+ else {
+ /* regular number */
+ const int new_exp = flt_e - 127;
+ if (new_exp < -14) {
+ /* The float32 lies in the range (0.0, min_normal16) and is rounded
+ * to a nearby float16 value. The result will be either zero, subnormal,
+ * or normal.
+ */
+ e = 0;
+ m = _mesa_lroundevenf((1 << 24) * fabsf(fi.f));
+ }
+ else if (new_exp > 15) {
+ /* map this value to infinity */
+ /* m = 0; - already set */
+ e = 31;
+ }
+ else {
+ /* The float32 lies in the range
+ * [min_normal16, max_normal16 + max_step16)
+ * and is rounded to a nearby float16 value. The result will be
+ * either normal or infinite.
+ */
+ e = new_exp + 15;
+ m = _mesa_lroundevenf(flt_m / (float) (1 << 13));
+ }
+ }
+
+ assert(0 <= m && m <= 1024);
+ if (m == 1024) {
+ /* The float32 was rounded upwards into the range of the next exponent,
+ * so bump the exponent. This correctly handles the case where f32
+ * should be rounded up to float16 infinity.
+ */
+ ++e;
+ m = 0;
+ }
+
+ result = (s << 15) | (e << 10) | m;
+ return result;
+}
+
+
+/**
+ * Convert a 2-byte half float to a 4-byte float.
+ * Based on code from:
+ * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
+ */
+float
+half_to_float(uint16_t val)
+{
+ /* XXX could also use a 64K-entry lookup table */
+ const int m = val & 0x3ff;
+ const int e = (val >> 10) & 0x1f;
+ const int s = (val >> 15) & 0x1;
+ int flt_m, flt_e, flt_s;
+ fi_type fi;
+ float result;
+
+ /* sign bit */
+ flt_s = s;
+
+ /* handle special cases */
+ if ((e == 0) && (m == 0)) {
+ /* zero */
+ flt_m = 0;
+ flt_e = 0;
+ }
+ else if ((e == 0) && (m != 0)) {
+ /* denorm -- denorm half will fit in non-denorm single */
+ const float half_denorm = 1.0f / 16384.0f; /* 2^-14 */
+ float mantissa = ((float) (m)) / 1024.0f;
+ float sign = s ? -1.0f : 1.0f;
+ return sign * mantissa * half_denorm;
+ }
+ else if ((e == 31) && (m == 0)) {
+ /* infinity */
+ flt_e = 0xff;
+ flt_m = 0;
+ }
+ else if ((e == 31) && (m != 0)) {
+ /* NaN */
+ flt_e = 0xff;
+ flt_m = 1;
+ }
+ else {
+ /* regular */
+ flt_e = e + 112;
+ flt_m = m << 13;
+ }
+
+ fi.i = (flt_s << 31) | (flt_e << 23) | flt_m;
+ result = fi.f;
+ return result;
+}
diff --git a/src/util/convert.h b/src/util/convert.h
new file mode 100644
index 0000000..30d36a1
--- /dev/null
+++ b/src/util/convert.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright © 2015 Red Hat
+ *
+ * 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 (including the next
+ * paragraph) 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 OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Rob Clark <robclark at freedesktop.org>
+ */
+
+#ifndef _MATH_H_
+#define _MATH_H_
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+uint16_t float_to_half(float val);
+float half_to_float(uint16_t val);
+
+#ifdef __cplusplus
+} /* extern C */
+#endif
+
+#endif /* _MATH_H_ */
--
2.4.3
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