src/gallium/drivers/llvmpipe/lp_bld_const.c

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  27
  28
  29 /**
  30  * @file
  31  * Helper functions for constant building.
  32  *
  33  * @author Jose Fonseca <jfonseca@vmware.com>
  34  */
  35
  36
  37 #include "util/u_debug.h"
  38
  39 #include "lp_bld_type.h"
  40 #include "lp_bld_const.h"
  41
  42
  43 /**
  44  * Shift of the unity.
  45  *
  46  * Same as lp_const_scale(), but in terms of shifts.
  47  */
  48 unsigned
  49 lp_const_shift(union lp_type type)
  50 {
  51    if(type.floating)
  52       return 0;
  53    else if(type.fixed)
  54       return type.width/2;
  55    else if(type.norm)
  56       return type.sign ? type.width - 1 : type.width;
  57    else
  58       return 0;
  59 }
  60
  61
  62 unsigned
  63 lp_const_offset(union lp_type type)
  64 {
  65    if(type.floating || type.fixed)
  66       return 0;
  67    else if(type.norm)
  68       return 1;
  69    else
  70       return 0;
  71 }
  72
  73
  74 /**
  75  * Scaling factor between the LLVM native value and its interpretation.
  76  *
  77  * This is 1.0 for all floating types and unnormalized integers, and something
  78  * else for the fixed points types and normalized integers.
  79  */
  80 double
  81 lp_const_scale(union lp_type type)
  82 {
  83    unsigned long long llscale;
  84    double dscale;
  85
  86    llscale = (unsigned long long)1 << lp_const_shift(type);
  87    llscale -= lp_const_offset(type);
  88    dscale = (double)llscale;
  89    assert((unsigned long long)dscale == llscale);
  90
  91    return dscale;
  92 }
  93
  94
  95 LLVMValueRef
  96 lp_build_undef(union lp_type type)
  97 {
  98    LLVMTypeRef vec_type = lp_build_vec_type(type);
  99    return LLVMGetUndef(vec_type);
 100 }
 101
 102
 103 LLVMValueRef
 104 lp_build_zero(union lp_type type)
 105 {
 106    LLVMTypeRef vec_type = lp_build_vec_type(type);
 107    return LLVMConstNull(vec_type);
 108 }
 109
 110
 111 LLVMValueRef
 112 lp_build_one(union lp_type type)
 113 {
 114    LLVMTypeRef elem_type;
 115    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
 116    unsigned i;
 117
 118    assert(type.length <= LP_MAX_VECTOR_LENGTH);
 119
 120    elem_type = lp_build_elem_type(type);
 121
 122    if(type.floating)
 123       elems[0] = LLVMConstReal(elem_type, 1.0);
 124    else if(type.fixed)
 125       elems[0] = LLVMConstInt(elem_type, 1LL << (type.width/2), 0);
 126    else if(!type.norm)
 127       elems[0] = LLVMConstInt(elem_type, 1, 0);
 128    else if(type.sign)
 129       elems[0] = LLVMConstInt(elem_type, (1LL << (type.width - 1)) - 1, 0);
 130    else {
 131       /* special case' -- 1.0 for normalized types is more easily attained if
 132        * we start with a vector consisting of all bits set */
 133       LLVMTypeRef vec_type = LLVMVectorType(elem_type, type.length);
 134       LLVMValueRef vec = LLVMConstAllOnes(vec_type);
 135
 136 #if 0
 137       if(type.sign)
 138          /* TODO: Unfortunately this caused "Tried to create a shift operation
 139           * on a non-integer type!" */
 140          vec = LLVMConstLShr(vec, lp_build_int_const_uni(type, 1));
 141 #endif
 142
 143       return vec;
 144    }
 145
 146    for(i = 1; i < type.length; ++i)
 147       elems[i] = elems[0];
 148
 149    return LLVMConstVector(elems, type.length);
 150 }
 151
 152
 153 LLVMValueRef
 154 lp_build_const_uni(union lp_type type,
 155                    double val)
 156 {
 157    LLVMTypeRef elem_type = lp_build_elem_type(type);
 158    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
 159    unsigned i;
 160
 161    assert(type.length <= LP_MAX_VECTOR_LENGTH);
 162
 163    if(type.floating) {
 164       elems[0] = LLVMConstReal(elem_type, val);
 165    }
 166    else {
 167       double dscale = lp_const_scale(type);
 168
 169       elems[0] = LLVMConstInt(elem_type, val*dscale + 0.5, 0);
 170    }
 171
 172    for(i = 1; i < type.length; ++i)
 173       elems[i] = elems[0];
 174
 175    return LLVMConstVector(elems, type.length);
 176 }
 177
 178
 179 LLVMValueRef
 180 lp_build_int_const_uni(union lp_type type,
 181                        long long val)
 182 {
 183    LLVMTypeRef elem_type = lp_build_int_elem_type(type);
 184    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
 185    unsigned i;
 186
 187    assert(type.length <= LP_MAX_VECTOR_LENGTH);
 188
 189    for(i = 0; i < type.length; ++i)
 190       elems[i] = LLVMConstInt(elem_type, val, type.sign ? 1 : 0);
 191
 192    return LLVMConstVector(elems, type.length);
 193 }
 194
 195
 196 LLVMValueRef
 197 lp_build_const_aos(union lp_type type,
 198                    double r, double g, double b, double a,
 199                    const unsigned char *swizzle)
 200 {
 201    const unsigned char default_swizzle[4] = {0, 1, 2, 3};
 202    LLVMTypeRef elem_type;
 203    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
 204    unsigned i;
 205
 206    assert(type.length % 4 == 0);
 207    assert(type.length <= LP_MAX_VECTOR_LENGTH);
 208
 209    elem_type = lp_build_elem_type(type);
 210
 211    if(swizzle == NULL)
 212       swizzle = default_swizzle;
 213
 214    if(type.floating) {
 215       elems[swizzle[0]] = LLVMConstReal(elem_type, r);
 216       elems[swizzle[1]] = LLVMConstReal(elem_type, g);
 217       elems[swizzle[2]] = LLVMConstReal(elem_type, b);
 218       elems[swizzle[3]] = LLVMConstReal(elem_type, a);
 219    }
 220    else {
 221       double dscale = lp_const_scale(type);
 222
 223       elems[swizzle[0]] = LLVMConstInt(elem_type, r*dscale + 0.5, 0);
 224       elems[swizzle[1]] = LLVMConstInt(elem_type, g*dscale + 0.5, 0);
 225       elems[swizzle[2]] = LLVMConstInt(elem_type, b*dscale + 0.5, 0);
 226       elems[swizzle[3]] = LLVMConstInt(elem_type, a*dscale + 0.5, 0);
 227    }
 228
 229    for(i = 4; i < type.length; ++i)
 230       elems[i] = elems[i % 4];
 231
 232    return LLVMConstVector(elems, type.length);
 233 }
 234
 235
 236 LLVMValueRef
 237 lp_build_const_mask_aos(union lp_type type,
 238                         boolean cond[4])
 239 {
 240    LLVMTypeRef elem_type = LLVMIntType(type.width);
 241    LLVMValueRef masks[LP_MAX_VECTOR_LENGTH];
 242    unsigned i, j;
 243
 244    assert(type.length <= LP_MAX_VECTOR_LENGTH);
 245
 246    for(j = 0; j < type.length; j += 4)
 247       for(i = 0; i < 4; ++i)
 248          masks[j + i] = LLVMConstInt(elem_type, cond[i] ? ~0 : 0, 0);
 249
 250    return LLVMConstVector(masks, type.length);
 251 }