glsl: move half<->float convertion to util

Needed in NIR too, so move out of mesa/main/imports.c

Reviewed-by: Jason Ekstrand <[email protected]>
Reviewed-by: Emil Velikov <[email protected]>
Signed-off-by: Rob Clark <[email protected]>

5 files changed, 3 insertions, 155 deletions

diff --git a/src/mesa/main/format_utils.h b/src/mesa/main/format_utils.h
index 618f43d0aaa..378997b38b2 100644
--- a/src/mesa/main/format_utils.h
+++ b/src/mesa/main/format_utils.h
@@ -34,6 +34,7 @@
 #include "imports.h"
 #include "macros.h"
 #include "util/rounding.h"
+#include "util/half_float.h"
 
 extern const mesa_array_format RGBA32_FLOAT;
 extern const mesa_array_format RGBA8_UBYTE;
diff --git a/src/mesa/main/imports.c b/src/mesa/main/imports.c
index 350e6752c8b..230ebbc67f4 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 90247587be3..042147fd8bb 100644
--- a/src/mesa/main/imports.h
+++ b/src/mesa/main/imports.h
@@ -396,13 +396,6 @@ _mesa_flsll(uint64_t n)
 #endif
 }
 
-
-extern GLhalfARB
-_mesa_float_to_half(float f);
-
-extern float
-_mesa_half_to_float(GLhalfARB h);
-
 static inline bool
 _mesa_half_is_negative(GLhalfARB h)
 {
diff --git a/src/mesa/main/mipmap.c b/src/mesa/main/mipmap.c
index ab16c2854a8..50469956c6e 100644
--- a/src/mesa/main/mipmap.c
+++ b/src/mesa/main/mipmap.c
@@ -37,6 +37,7 @@
 #include "texstore.h"
 #include "image.h"
 #include "macros.h"
+#include "util/half_float.h"
 #include "../../gallium/auxiliary/util/u_format_rgb9e5.h"
 #include "../../gallium/auxiliary/util/u_format_r11g11b10f.h"
 
diff --git a/src/mesa/main/texcompress_bptc.c b/src/mesa/main/texcompress_bptc.c
index f0f6553a01b..26e59158007 100644
--- a/src/mesa/main/texcompress_bptc.c
+++ b/src/mesa/main/texcompress_bptc.c
@@ -30,6 +30,7 @@
 #include "texcompress.h"
 #include "texcompress_bptc.h"
 #include "util/format_srgb.h"
+#include "util/half_float.h"
 #include "texstore.h"
 #include "macros.h"
 #include "image.h"