static nir_ssa_def *
build_frexp(nir_builder *b, nir_ssa_def *x, nir_ssa_def **exponent)
{
nir_ssa_def *abs_x = nir_fabs(b, x);
nir_ssa_def *zero = nir_imm_float(b, 0.0f);
/* Single-precision floating-point values are stored as
* 1 sign bit;
* 8 exponent bits;
* 23 mantissa bits.
*
* An exponent shift of 23 will shift the mantissa out, leaving only the
* exponent and sign bit (which itself may be zero, if the absolute value
* was taken before the bitcast and shift.
*/
nir_ssa_def *exponent_shift = nir_imm_int(b, 23);
nir_ssa_def *exponent_bias = nir_imm_int(b, -126);
nir_ssa_def *sign_mantissa_mask = nir_imm_int(b, 0x807fffffu);
/* Exponent of floating-point values in the range [0.5, 1.0). */
nir_ssa_def *exponent_value = nir_imm_int(b, 0x3f000000u);
nir_ssa_def *is_not_zero = nir_fne(b, abs_x, zero);
*exponent =
nir_iadd(b, nir_ushr(b, abs_x, exponent_shift),
nir_bcsel(b, is_not_zero, exponent_bias, zero));
return nir_ior(b, nir_iand(b, x, sign_mantissa_mask),
nir_bcsel(b, is_not_zero, exponent_value, zero));
}
static nir_ssa_def *
build_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
{
nir_ssa_def *zero = nir_imm_float(b, 0.0f);
/* If |x| >= 1.0e-8 * |y|: */
nir_ssa_def *condition =
nir_fge(b, nir_fabs(b, x),
nir_fmul(b, nir_imm_float(b, 1.0e-8f), nir_fabs(b, y)));
/* Then...call atan(y/x) and fix it up: */
nir_ssa_def *atan1 = build_atan(b, nir_fdiv(b, y, x));
nir_ssa_def *r_then =
nir_bcsel(b, nir_flt(b, x, zero),
nir_fadd(b, atan1,
nir_bcsel(b, nir_fge(b, y, zero),
nir_imm_float(b, M_PIf),
nir_imm_float(b, -M_PIf))),
atan1);
/* Else... */
nir_ssa_def *r_else =
nir_fmul(b, nir_fsign(b, y), nir_imm_float(b, M_PI_2f));
return nir_bcsel(b, condition, r_then, r_else);
}
/* NIR equiv of TGSI CMP instruction: */
static nir_ssa_def *
nir_cmp(nir_builder *b, nir_ssa_def *src0, nir_ssa_def *src1, nir_ssa_def *src2)
{
return nir_bcsel(b, nir_flt(b, src0, nir_imm_float(b, 0.0)), src1, src2);
}
static void
convert_instr(nir_builder *bld, nir_alu_instr *alu)
{
nir_ssa_def *numer, *denom, *af, *bf, *a, *b, *q, *r;
nir_op op = alu->op;
bool is_signed;
if ((op != nir_op_idiv) &&
(op != nir_op_udiv) &&
(op != nir_op_umod))
return;
is_signed = (op == nir_op_idiv);
bld->cursor = nir_before_instr(&alu->instr);
numer = nir_ssa_for_alu_src(bld, alu, 0);
denom = nir_ssa_for_alu_src(bld, alu, 1);
if (is_signed) {
af = nir_i2f(bld, numer);
bf = nir_i2f(bld, denom);
af = nir_fabs(bld, af);
bf = nir_fabs(bld, bf);
a = nir_iabs(bld, numer);
b = nir_iabs(bld, denom);
} else {
af = nir_u2f(bld, numer);
bf = nir_u2f(bld, denom);
a = numer;
b = denom;
}
/* get first result: */
bf = nir_frcp(bld, bf);
bf = nir_isub(bld, bf, nir_imm_int(bld, 2)); /* yes, really */
q = nir_fmul(bld, af, bf);
if (is_signed) {
q = nir_f2i(bld, q);
} else {
q = nir_f2u(bld, q);
}
/* get error of first result: */
r = nir_imul(bld, q, b);
r = nir_isub(bld, a, r);
r = nir_u2f(bld, r);
r = nir_fmul(bld, r, bf);
r = nir_f2u(bld, r);
/* add quotients: */
q = nir_iadd(bld, q, r);
/* correction: if modulus >= divisor, add 1 */
r = nir_imul(bld, q, b);
r = nir_isub(bld, a, r);
r = nir_uge(bld, r, b);
r = nir_b2i(bld, r);
q = nir_iadd(bld, q, r);
if (is_signed) {
/* fix the sign: */
r = nir_ixor(bld, numer, denom);
r = nir_ushr(bld, r, nir_imm_int(bld, 31));
r = nir_i2b(bld, r);
b = nir_ineg(bld, q);
q = nir_bcsel(bld, r, b, q);
}
if (op == nir_op_umod) {
/* division result in q */
r = nir_imul(bld, q, b);
q = nir_isub(bld, a, r);
}
assert(alu->dest.dest.is_ssa);
nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa, nir_src_for_ssa(q));
}
static void
handle_glsl450_alu(struct vtn_builder *b, enum GLSLstd450 entrypoint,
const uint32_t *w, unsigned count)
{
struct nir_builder *nb = &b->nb;
const struct glsl_type *dest_type =
vtn_value(b, w[1], vtn_value_type_type)->type->type;
struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_ssa);
val->ssa = vtn_create_ssa_value(b, dest_type);
/* Collect the various SSA sources */
unsigned num_inputs = count - 5;
nir_ssa_def *src[3] = { NULL, };
for (unsigned i = 0; i < num_inputs; i++)
src[i] = vtn_ssa_value(b, w[i + 5])->def;
switch (entrypoint) {
case GLSLstd450Radians:
val->ssa->def = nir_fmul(nb, src[0], nir_imm_float(nb, 0.01745329251));
return;
case GLSLstd450Degrees:
val->ssa->def = nir_fmul(nb, src[0], nir_imm_float(nb, 57.2957795131));
return;
case GLSLstd450Tan:
val->ssa->def = nir_fdiv(nb, nir_fsin(nb, src[0]),
nir_fcos(nb, src[0]));
return;
case GLSLstd450Modf: {
nir_ssa_def *sign = nir_fsign(nb, src[0]);
nir_ssa_def *abs = nir_fabs(nb, src[0]);
val->ssa->def = nir_fmul(nb, sign, nir_ffract(nb, abs));
nir_store_deref_var(nb, vtn_nir_deref(b, w[6]),
nir_fmul(nb, sign, nir_ffloor(nb, abs)), 0xf);
return;
}
case GLSLstd450ModfStruct: {
nir_ssa_def *sign = nir_fsign(nb, src[0]);
nir_ssa_def *abs = nir_fabs(nb, src[0]);
assert(glsl_type_is_struct(val->ssa->type));
val->ssa->elems[0]->def = nir_fmul(nb, sign, nir_ffract(nb, abs));
val->ssa->elems[1]->def = nir_fmul(nb, sign, nir_ffloor(nb, abs));
return;
}
case GLSLstd450Step:
val->ssa->def = nir_sge(nb, src[1], src[0]);
return;
case GLSLstd450Length:
val->ssa->def = build_length(nb, src[0]);
return;
case GLSLstd450Distance:
val->ssa->def = build_length(nb, nir_fsub(nb, src[0], src[1]));
return;
case GLSLstd450Normalize:
val->ssa->def = nir_fdiv(nb, src[0], build_length(nb, src[0]));
return;
case GLSLstd450Exp:
val->ssa->def = build_exp(nb, src[0]);
return;
case GLSLstd450Log:
val->ssa->def = build_log(nb, src[0]);
return;
case GLSLstd450FClamp:
val->ssa->def = build_fclamp(nb, src[0], src[1], src[2]);
return;
case GLSLstd450UClamp:
val->ssa->def = nir_umin(nb, nir_umax(nb, src[0], src[1]), src[2]);
return;
case GLSLstd450SClamp:
val->ssa->def = nir_imin(nb, nir_imax(nb, src[0], src[1]), src[2]);
return;
case GLSLstd450Cross: {
unsigned yzx[4] = { 1, 2, 0, 0 };
unsigned zxy[4] = { 2, 0, 1, 0 };
val->ssa->def =
nir_fsub(nb, nir_fmul(nb, nir_swizzle(nb, src[0], yzx, 3, true),
nir_swizzle(nb, src[1], zxy, 3, true)),
nir_fmul(nb, nir_swizzle(nb, src[0], zxy, 3, true),
nir_swizzle(nb, src[1], yzx, 3, true)));
return;
}
case GLSLstd450SmoothStep: {
/* t = clamp((x - edge0) / (edge1 - edge0), 0, 1) */
nir_ssa_def *t =
build_fclamp(nb, nir_fdiv(nb, nir_fsub(nb, src[2], src[0]),
nir_fsub(nb, src[1], src[0])),
nir_imm_float(nb, 0.0), nir_imm_float(nb, 1.0));
/* result = t * t * (3 - 2 * t) */
val->ssa->def =
nir_fmul(nb, t, nir_fmul(nb, t,
nir_fsub(nb, nir_imm_float(nb, 3.0),
nir_fmul(nb, nir_imm_float(nb, 2.0), t))));
return;
}
case GLSLstd450FaceForward:
val->ssa->def =
nir_bcsel(nb, nir_flt(nb, nir_fdot(nb, src[2], src[1]),
nir_imm_float(nb, 0.0)),
src[0], nir_fneg(nb, src[0]));
return;
case GLSLstd450Reflect:
/* I - 2 * dot(N, I) * N */
val->ssa->def =
nir_fsub(nb, src[0], nir_fmul(nb, nir_imm_float(nb, 2.0),
nir_fmul(nb, nir_fdot(nb, src[0], src[1]),
src[1])));
return;
case GLSLstd450Refract: {
nir_ssa_def *I = src[0];
nir_ssa_def *N = src[1];
nir_ssa_def *eta = src[2];
nir_ssa_def *n_dot_i = nir_fdot(nb, N, I);
nir_ssa_def *one = nir_imm_float(nb, 1.0);
nir_ssa_def *zero = nir_imm_float(nb, 0.0);
/* k = 1.0 - eta * eta * (1.0 - dot(N, I) * dot(N, I)) */
nir_ssa_def *k =
nir_fsub(nb, one, nir_fmul(nb, eta, nir_fmul(nb, eta,
nir_fsub(nb, one, nir_fmul(nb, n_dot_i, n_dot_i)))));
nir_ssa_def *result =
nir_fsub(nb, nir_fmul(nb, eta, I),
nir_fmul(nb, nir_fadd(nb, nir_fmul(nb, eta, n_dot_i),
nir_fsqrt(nb, k)), N));
/* XXX: bcsel, or if statement? */
val->ssa->def = nir_bcsel(nb, nir_flt(nb, k, zero), zero, result);
return;
}
case GLSLstd450Sinh:
/* 0.5 * (e^x - e^(-x)) */
val->ssa->def =
nir_fmul(nb, nir_imm_float(nb, 0.5f),
nir_fsub(nb, build_exp(nb, src[0]),
build_exp(nb, nir_fneg(nb, src[0]))));
return;
case GLSLstd450Cosh:
/* 0.5 * (e^x + e^(-x)) */
val->ssa->def =
nir_fmul(nb, nir_imm_float(nb, 0.5f),
nir_fadd(nb, build_exp(nb, src[0]),
build_exp(nb, nir_fneg(nb, src[0]))));
return;
case GLSLstd450Tanh:
/* (0.5 * (e^x - e^(-x))) / (0.5 * (e^x + e^(-x))) */
val->ssa->def =
nir_fdiv(nb, nir_fmul(nb, nir_imm_float(nb, 0.5f),
nir_fsub(nb, build_exp(nb, src[0]),
build_exp(nb, nir_fneg(nb, src[0])))),
nir_fmul(nb, nir_imm_float(nb, 0.5f),
nir_fadd(nb, build_exp(nb, src[0]),
build_exp(nb, nir_fneg(nb, src[0])))));
return;
case GLSLstd450Asinh:
val->ssa->def = nir_fmul(nb, nir_fsign(nb, src[0]),
build_log(nb, nir_fadd(nb, nir_fabs(nb, src[0]),
nir_fsqrt(nb, nir_fadd(nb, nir_fmul(nb, src[0], src[0]),
nir_imm_float(nb, 1.0f))))));
return;
case GLSLstd450Acosh:
val->ssa->def = build_log(nb, nir_fadd(nb, src[0],
nir_fsqrt(nb, nir_fsub(nb, nir_fmul(nb, src[0], src[0]),
nir_imm_float(nb, 1.0f)))));
return;
case GLSLstd450Atanh: {
nir_ssa_def *one = nir_imm_float(nb, 1.0);
val->ssa->def = nir_fmul(nb, nir_imm_float(nb, 0.5f),
build_log(nb, nir_fdiv(nb, nir_fadd(nb, one, src[0]),
nir_fsub(nb, one, src[0]))));
return;
}
case GLSLstd450Asin:
val->ssa->def = build_asin(nb, src[0], 0.086566724, -0.03102955);
return;
case GLSLstd450Acos:
val->ssa->def = nir_fsub(nb, nir_imm_float(nb, M_PI_2f),
build_asin(nb, src[0], 0.08132463, -0.02363318));
return;
case GLSLstd450Atan:
val->ssa->def = build_atan(nb, src[0]);
return;
case GLSLstd450Atan2:
val->ssa->def = build_atan2(nb, src[0], src[1]);
return;
case GLSLstd450Frexp: {
nir_ssa_def *exponent;
val->ssa->def = build_frexp(nb, src[0], &exponent);
nir_store_deref_var(nb, vtn_nir_deref(b, w[6]), exponent, 0xf);
return;
}
case GLSLstd450FrexpStruct: {
assert(glsl_type_is_struct(val->ssa->type));
val->ssa->elems[0]->def = build_frexp(nb, src[0],
&val->ssa->elems[1]->def);
return;
}
default:
val->ssa->def =
nir_build_alu(&b->nb, vtn_nir_alu_op_for_spirv_glsl_opcode(entrypoint),
src[0], src[1], src[2], NULL);
return;
}
}
