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nir/format_convert: Add a function to pack RGB9_E5 formats 

Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
This commit is contained in:
Jason Ekstrand 2018-01-25 23:06:11 -08:00
parent 4e337b42f9
commit 9981709d8f
1 changed files with 64 additions and 0 deletions
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64
src/compiler/nir/nir_format_convert.h
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@ -23,6 +23,8 @@
#include "nir_builder.h"
#include "util/format_rgb9e5.h"
static inline nir_ssa_def *
nir_shift(nir_builder *b, nir_ssa_def *value, int left_shift)
{
@ -168,3 +170,65 @@ nir_format_pack_r11g11b10f(nir_builder *b, nir_ssa_def *color)
return packed;
}
static inline nir_ssa_def *
nir_format_pack_r9g9b9e5(nir_builder *b, nir_ssa_def *color)
{
/* See also float3_to_rgb9e5 */
/* First, we need to clamp it to range. */
nir_ssa_def *clamped = nir_fmin(b, color, nir_imm_float(b, MAX_RGB9E5));
/* Get rid of negatives and NaN */
clamped = nir_bcsel(b, nir_ult(b, nir_imm_int(b, 0x7f800000), color),
nir_imm_float(b, 0), clamped);
/* maxrgb.u = MAX3(rc.u, gc.u, bc.u); */
nir_ssa_def *maxu = nir_umax(b, nir_channel(b, clamped, 0),
nir_umax(b, nir_channel(b, clamped, 1),
nir_channel(b, clamped, 2)));
/* maxrgb.u += maxrgb.u & (1 << (23-9)); */
maxu = nir_iadd(b, maxu, nir_iand(b, maxu, nir_imm_int(b, 1 << 14)));
/* exp_shared = MAX2((maxrgb.u >> 23), -RGB9E5_EXP_BIAS - 1 + 127) +
* 1 + RGB9E5_EXP_BIAS - 127;
*/
nir_ssa_def *exp_shared =
nir_iadd(b, nir_umax(b, nir_ushr(b, maxu, nir_imm_int(b, 23)),
nir_imm_int(b, -RGB9E5_EXP_BIAS - 1 + 127)),
nir_imm_int(b, 1 + RGB9E5_EXP_BIAS - 127));
/* revdenom_biasedexp = 127 - (exp_shared - RGB9E5_EXP_BIAS -
* RGB9E5_MANTISSA_BITS) + 1;
*/
nir_ssa_def *revdenom_biasedexp =
nir_isub(b, nir_imm_int(b, 127 + RGB9E5_EXP_BIAS +
RGB9E5_MANTISSA_BITS + 1),
exp_shared);
/* revdenom.u = revdenom_biasedexp << 23; */
nir_ssa_def *revdenom =
nir_ishl(b, revdenom_biasedexp, nir_imm_int(b, 23));
/* rm = (int) (rc.f * revdenom.f);
* gm = (int) (gc.f * revdenom.f);
* bm = (int) (bc.f * revdenom.f);
*/
nir_ssa_def *mantissa =
nir_f2i32(b, nir_fmul(b, clamped, revdenom));
/* rm = (rm & 1) + (rm >> 1);
* gm = (gm & 1) + (gm >> 1);
* bm = (bm & 1) + (bm >> 1);
*/
mantissa = nir_iadd(b, nir_iand(b, mantissa, nir_imm_int(b, 1)),
nir_ushr(b, mantissa, nir_imm_int(b, 1)));
nir_ssa_def *packed = nir_channel(b, mantissa, 0);
packed = nir_mask_shift_or(b, packed, nir_channel(b, mantissa, 1), ~0, 9);
packed = nir_mask_shift_or(b, packed, nir_channel(b, mantissa, 2), ~0, 18);
packed = nir_mask_shift_or(b, packed, exp_shared, ~0, 27);
return packed;
}