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/*
* Copyright (C) 2020 Collabora Ltd.
*
* 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 (Collabora):
* Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
*/
#include "compiler.h"
/* Bifrost requires special functions to be lowered in various machine specific
* ways. The routines in this file are used in codegen for this. */
/* New Bifrost has a FEXP2_FAST instruction but requires an auxiliary
* parameter. */
static void
bi_emit_fexp2_new(bi_context *ctx, nir_alu_instr *instr)
{
/* FMA_MSCALE T, X, 1.0, 0, 0x18 */
bi_instruction mscale = {
.type = BI_FMA,
.op = { .mscale = true },
.dest = bi_make_temp(ctx),
.dest_type = nir_type_float32,
.src = {
bir_src_index(&instr->src[0].src),
BIR_INDEX_CONSTANT | 0,
BIR_INDEX_ZERO,
BIR_INDEX_CONSTANT | 32,
},
.src_types = {
nir_type_float32,
nir_type_float32,
nir_type_float32,
nir_type_int32,
},
.constant = {
/* 0x3f80000000 = 1.0f as fp32
* 24 = shift to multiply by 2^24 */
.u64 = (0x3f800000) | (24ull << 32)
}
};
/* F2I_RTE T, T */
bi_instruction f2i = {
.type = BI_CONVERT,
.dest = bi_make_temp(ctx),
.dest_type = nir_type_int32,
.src = { mscale.dest },
.src_types = { nir_type_float32 },
.roundmode = BIFROST_RTE
};
/* FEXP2_FAST T, T, X */
bi_instruction fexp = {
.type = BI_SPECIAL,
.op = { .special = BI_SPECIAL_EXP2_LOW },
.dest = bir_dest_index(&instr->dest.dest),
.dest_type = nir_type_float32,
.src = { f2i.dest, mscale.src[0] },
.src_types = { nir_type_int32, nir_type_float32 },
};
bi_emit(ctx, mscale);
bi_emit(ctx, f2i);
bi_emit(ctx, fexp);
}
/* Even on new Bifrost, there are a bunch of reductions to do */
static void
bi_emit_flog2_new(bi_context *ctx, nir_alu_instr *instr)
{
/* LOG_FREXPE X */
bi_instruction frexpe = {
.type = BI_FREXP,
.op = { .frexp = BI_FREXPE_LOG },
.dest = bi_make_temp(ctx),
.dest_type = nir_type_int32,
.src = { bir_src_index(&instr->src[0].src) },
.src_types = { nir_type_float32 }
};
/* I32_TO_F32 m */
bi_instruction i2f = {
.type = BI_CONVERT,
.dest = bi_make_temp(ctx),
.dest_type = nir_type_float32,
.src = { frexpe.dest },
.src_types = { nir_type_int32 },
.roundmode = BIFROST_RTZ
};
/* ADD_FREXPM (x-1), -1.0, X */
bi_instruction x_minus_1 = {
.type = BI_REDUCE_FMA,
.op = { .reduce = BI_REDUCE_ADD_FREXPM },
.dest = bi_make_temp(ctx),
.dest_type = nir_type_float32,
.src = {
BIR_INDEX_CONSTANT,
bir_src_index(&instr->src[0].src),
},
.src_types = { nir_type_float32, nir_type_float32 },
.constant = {
.u64 = 0xBF800000 /* -1.0 */
}
};
/* FLOG2_HELP log2(x)/(x-1), x */
bi_instruction help = {
.type = BI_TABLE,
.op = { .table = BI_TABLE_LOG2_U_OVER_U_1_LOW },
.dest = bi_make_temp(ctx),
.dest_type = nir_type_float32,
.src = { bir_src_index(&instr->src[0].src) },
.src_types = { nir_type_float32 },
};
/* FMA log2(x)/(x - 1), (x - 1), M */
bi_instruction fma = {
.type = BI_FMA,
.dest = bir_dest_index(&instr->dest.dest),
.dest_type = nir_type_float32,
.src = {
help.dest,
x_minus_1.dest,
i2f.dest
},
.src_types = {
nir_type_float32,
nir_type_float32,
nir_type_float32
}
};
bi_emit(ctx, frexpe);
bi_emit(ctx, i2f);
bi_emit(ctx, x_minus_1);
bi_emit(ctx, help);
bi_emit(ctx, fma);
}
void
bi_emit_fexp2(bi_context *ctx, nir_alu_instr *instr)
{
/* TODO: G71 */
bi_emit_fexp2_new(ctx, instr);
}
void
bi_emit_flog2(bi_context *ctx, nir_alu_instr *instr)
{
/* TODO: G71 */
bi_emit_flog2_new(ctx, instr);
}
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