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-rw-r--r--src/gallium/drivers/llvmpipe/lp_bld_arit.c137
1 files changed, 99 insertions, 38 deletions
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_arit.c b/src/gallium/drivers/llvmpipe/lp_bld_arit.c
index a322ec233e8..7b3932f5222 100644
--- a/src/gallium/drivers/llvmpipe/lp_bld_arit.c
+++ b/src/gallium/drivers/llvmpipe/lp_bld_arit.c
@@ -45,6 +45,7 @@
*/
+#include "util/u_memory.h"
#include "util/u_debug.h"
#include "util/u_string.h"
@@ -651,37 +652,36 @@ lp_build_sin(struct lp_build_context *bld,
LLVMValueRef
lp_build_pow(struct lp_build_context *bld,
- LLVMValueRef a,
- LLVMValueRef b)
+ LLVMValueRef x,
+ LLVMValueRef y)
{
- const union lp_type type = bld->type;
- LLVMTypeRef vec_type = lp_build_vec_type(type);
- char intrinsic[32];
-
/* TODO: optimize the constant case */
+ if(LLVMIsConstant(x) && LLVMIsConstant(y))
+ debug_printf("%s: inefficient/imprecise constant arithmetic\n");
- assert(type.floating);
- util_snprintf(intrinsic, sizeof intrinsic, "llvm.pow.v%uf%u", type.length, type.width);
-
- return lp_build_intrinsic_binary(bld->builder, intrinsic, vec_type, a, b);
+ return lp_build_exp2(bld, lp_build_mul(bld, lp_build_log2(bld, x), y));
}
LLVMValueRef
lp_build_exp(struct lp_build_context *bld,
- LLVMValueRef a)
+ LLVMValueRef x)
{
- /* FIXME: optimize */
- return lp_build_pow(bld, lp_build_const_uni(bld->type, 2.7182818284590452354), a);
+ /* log2(e) = 1/log(2) */
+ LLVMValueRef log2e = lp_build_const_uni(bld->type, 1.4426950408889634);
+
+ return lp_build_mul(bld, log2e, lp_build_exp2(bld, x));
}
LLVMValueRef
lp_build_log(struct lp_build_context *bld,
- LLVMValueRef a)
+ LLVMValueRef x)
{
- /* FIXME: implement */
- return bld->undef;
+ /* log(2) */
+ LLVMValueRef log2 = lp_build_const_uni(bld->type, 1.4426950408889634);
+
+ return lp_build_mul(bld, log2, lp_build_exp2(bld, x));
}
@@ -699,6 +699,10 @@ lp_build_polynomial(struct lp_build_context *bld,
LLVMValueRef res = NULL;
unsigned i;
+ /* TODO: optimize the constant case */
+ if(LLVMIsConstant(x))
+ debug_printf("%s: inefficient/imprecise constant arithmetic\n");
+
for (i = num_coeffs; i--; ) {
LLVMValueRef coeff = lp_build_const_uni(type, coeffs[i]);
if(res)
@@ -714,16 +718,84 @@ lp_build_polynomial(struct lp_build_context *bld,
}
+/**
+ * Minimax polynomial fit of 2**x, in range [-0.5, 0.5[
+ */
+const double lp_build_exp2_polynomial[] = {
+#if EXP_POLY_DEGREE == 5
+ 9.9999994e-1, 6.9315308e-1, 2.4015361e-1, 5.5826318e-2, 8.9893397e-3, 1.8775767e-3
+#elif EXP_POLY_DEGREE == 4
+ 1.0000026, 6.9300383e-1, 2.4144275e-1, 5.2011464e-2, 1.3534167e-2
+#elif EXP_POLY_DEGREE == 3
+ 9.9992520e-1, 6.9583356e-1, 2.2606716e-1, 7.8024521e-2
+#elif EXP_POLY_DEGREE == 2
+ 1.0017247, 6.5763628e-1, 3.3718944e-1
+#else
+#error
+#endif
+};
+
+
LLVMValueRef
lp_build_exp2(struct lp_build_context *bld,
- LLVMValueRef a)
+ LLVMValueRef x)
{
- /* FIXME: optimize */
- return lp_build_pow(bld, lp_build_const_uni(bld->type, 2.0), a);
+ const union lp_type type = bld->type;
+ LLVMTypeRef vec_type = lp_build_vec_type(type);
+ LLVMTypeRef int_vec_type = lp_build_int_vec_type(type);
+ LLVMValueRef ipart;
+ LLVMValueRef fpart, expipart, expfpart;
+
+ /* TODO: optimize the constant case */
+ if(LLVMIsConstant(x))
+ debug_printf("%s: inefficient/imprecise constant arithmetic\n");
+
+ assert(type.floating && type.width == 32);
+
+ x = lp_build_min(bld, x, lp_build_const_uni(type, 129.0));
+ x = lp_build_max(bld, x, lp_build_const_uni(type, -126.99999));
+
+ /* ipart = int(x - 0.5) */
+ ipart = LLVMBuildSub(bld->builder, x, lp_build_const_uni(type, 0.5f), "");
+ ipart = LLVMBuildFPToSI(bld->builder, ipart, int_vec_type, "");
+
+ /* fpart = x - ipart */
+ fpart = LLVMBuildSIToFP(bld->builder, ipart, vec_type, "");
+ fpart = LLVMBuildSub(bld->builder, x, fpart, "");
+
+ /* expipart = (float) (1 << ipart) */
+ expipart = LLVMBuildAdd(bld->builder, ipart, lp_build_int_const_uni(type, 127), "");
+ expipart = LLVMBuildShl(bld->builder, expipart, lp_build_int_const_uni(type, 23), "");
+ expipart = LLVMBuildBitCast(bld->builder, expipart, vec_type, "");
+
+ expfpart = lp_build_polynomial(bld, fpart, lp_build_exp2_polynomial,
+ Elements(lp_build_exp2_polynomial));
+
+ return LLVMBuildMul(bld->builder, expipart, expfpart, "");
}
/**
+ * Minimax polynomial fit of log2(x)/(x - 1), for x in range [1, 2[
+ * These coefficients can be generate with
+ * http://www.boost.org/doc/libs/1_36_0/libs/math/doc/sf_and_dist/html/math_toolkit/toolkit/internals2/minimax.html
+ */
+const double lp_build_log2_polynomial[] = {
+#if LOG_POLY_DEGREE == 6
+ 3.11578814719469302614, -3.32419399085241980044, 2.59883907202499966007, -1.23152682416275988241, 0.318212422185251071475, -0.0344359067839062357313
+#elif LOG_POLY_DEGREE == 5
+ 2.8882704548164776201, -2.52074962577807006663, 1.48116647521213171641, -0.465725644288844778798, 0.0596515482674574969533
+#elif LOG_POLY_DEGREE == 4
+ 2.61761038894603480148, -1.75647175389045657003, 0.688243882994381274313, -0.107254423828329604454
+#elif LOG_POLY_DEGREE == 3
+ 2.28330284476918490682, -1.04913055217340124191, 0.204446009836232697516
+#else
+#error
+#endif
+};
+
+
+/**
* See http://www.devmaster.net/forums/showthread.php?p=43580
*/
LLVMValueRef
@@ -744,6 +816,12 @@ lp_build_log2(struct lp_build_context *bld,
LLVMValueRef mant;
LLVMValueRef logmant;
+ /* TODO: optimize the constant case */
+ if(LLVMIsConstant(x))
+ debug_printf("%s: inefficient/imprecise constant arithmetic\n");
+
+ assert(type.floating && type.width == 32);
+
/* exp = (float) exponent(x) */
exp = LLVMBuildAnd(bld->builder, i, expmask, "");
exp = LLVMBuildLShr(bld->builder, exp, lp_build_int_const_uni(type, 23), "");
@@ -755,25 +833,8 @@ lp_build_log2(struct lp_build_context *bld,
mant = LLVMBuildOr(bld->builder, mant, one, "");
mant = LLVMBuildSIToFP(bld->builder, mant, vec_type, "");
- /* Minimax polynomial fit of log2(x)/(x - 1), for x in range [1, 2[
- * These coefficients can be generate with
- * http://www.boost.org/doc/libs/1_36_0/libs/math/doc/sf_and_dist/html/math_toolkit/toolkit/internals2/minimax.html
- */
- const double polynomial[] = {
-#if LOG_POLY_DEGREE == 6
- 3.11578814719469302614, -3.32419399085241980044, 2.59883907202499966007, -1.23152682416275988241, 0.318212422185251071475, -0.0344359067839062357313
-#elif LOG_POLY_DEGREE == 5
- 2.8882704548164776201, -2.52074962577807006663, 1.48116647521213171641, -0.465725644288844778798, 0.0596515482674574969533
-#elif LOG_POLY_DEGREE == 4
- 2.61761038894603480148, -1.75647175389045657003, 0.688243882994381274313, -0.107254423828329604454
-#elif LOG_POLY_DEGREE == 3
- 2.28330284476918490682, -1.04913055217340124191, 0.204446009836232697516
-#else
-#error
-#endif
- };
-
- logmant = lp_build_polynomial(bld, mant, polynomial, sizeof(polynomial)/sizeof(polynomial[0]));
+ logmant = lp_build_polynomial(bld, mant, lp_build_log2_polynomial,
+ Elements(lp_build_log2_polynomial));
/* This effectively increases the polynomial degree by one, but ensures that log2(1) == 0*/
logmant = LLVMBuildMul(bld->builder, logmant, LLVMBuildMul(bld->builder, mant, bld->one, ""), "");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 14:10:15 +0000