diff options
| -rw-r--r-- | src/gallium/drivers/llvmpipe/lp_bld_arit.c | 137 |
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, ""), ""); |