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gallium/util: Switch util_float_to_half to _mesa_float_to_half()'s impl. 

The util_float_to_half() implementation was much smaller, but when trying
to switch _mesa_float_to_half to it, many testcases
(dEQP-VK.spirv_assembly.instruction.graphics.opquantize.*,
piglit.spec.arb_shading_language_packing.*packhalf2x16) start failing on
Intel.  Replace the broken impl so that people don't have to debug it
later.

Acked-by: Michel Dänzer <mdaenzer@redhat.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3699>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3699>
This commit is contained in:
Eric Anholt 2019-06-27 16:04:42 -07:00 committed by Marge Bot
parent 8e4e2cedcf
commit 8b8af6d398
1 changed files with 2 additions and 52 deletions
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54
src/gallium/auxiliary/util/u_half.h
View File

@ -30,6 +30,7 @@
#include "pipe/p_compiler.h"
#include "util/u_math.h"
#include "util/half_float.h"
#ifdef __cplusplus
extern "C" {
@ -46,58 +47,7 @@ extern "C" {
static inline uint16_t
util_float_to_half(float f)
{
uint32_t sign_mask = 0x80000000;
uint32_t round_mask = ~0xfff;
uint32_t f32inf = 0xff << 23;
uint32_t f16inf = 0x1f << 23;
uint32_t sign;
union fi magic;
union fi f32;
uint16_t f16;
magic.ui = 0xf << 23;
f32.f = f;
/* Sign */
sign = f32.ui & sign_mask;
f32.ui ^= sign;
if (f32.ui == f32inf) {
/* Inf */
f16 = 0x7c00;
} else if (f32.ui > f32inf) {
/* NaN */
f16 = 0x7e00;
} else {
/* Number */
f32.ui &= round_mask;
f32.f *= magic.f;
f32.ui -= round_mask;
/*
* XXX: The magic mul relies on denorms being available, otherwise
* all f16 denorms get flushed to zero - hence when this is used
* for tgsi_exec in softpipe we won't get f16 denorms.
*/
/*
* Clamp to max finite value if overflowed.
* OpenGL has completely undefined rounding behavior for float to
* half-float conversions, and this matches what is mandated for float
* to fp11/fp10, which recommend round-to-nearest-finite too.
* (d3d10 is deeply unhappy about flushing such values to infinity, and
* while it also mandates round-to-zero it doesn't care nearly as much
* about that.)
*/
if (f32.ui > f16inf)
f32.ui = f16inf - 1;
f16 = f32.ui >> 13;
}
/* Sign */
f16 |= sign >> 16;
return f16;
return _mesa_float_to_half(f);
}
static inline float