src/gallium/drivers/llvmpipe/lp_bld_pack.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2009 VMware, Inc.
   4  * All Rights Reserved.
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   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
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   9  * without limitation the rights to use, copy, modify, merge, publish,
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  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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  25  *
  26  **************************************************************************/
  27
  28
  29 #include "util/u_format.h"
  30
  31 #include "lp_bld.h"
  32
  33
  34 LLVMValueRef
  35 lp_build_pack_rgba(LLVMBuilderRef builder,
  36                    enum pipe_format format,
  37                    LLVMValueRef rgba)
  38 {
  39    const struct util_format_description *desc;
  40    LLVMTypeRef type;
  41    LLVMValueRef packed = NULL;
  42    LLVMValueRef swizzles[4];
  43    LLVMValueRef shifted, casted, scaled, unswizzled;
  44    LLVMValueRef shifts[4];
  45    LLVMValueRef scales[4];
  46    bool normalized;
  47    unsigned shift;
  48    unsigned i, j;
  49
  50    desc = util_format_description(format);
  51
  52    assert(desc->layout == UTIL_FORMAT_LAYOUT_ARITH);
  53    assert(desc->block.width == 1);
  54    assert(desc->block.height == 1);
  55
  56    type = LLVMIntType(desc->block.bits);
  57
  58    /* Unswizzle the color components into the source vector. */
  59    for (i = 0; i < 4; ++i) {
  60       for (j = 0; j < 4; ++j) {
  61          if (desc->swizzle[j] == i)
  62             break;
  63       }
  64       if (j < 4)
  65          swizzles[i] = LLVMConstInt(LLVMInt32Type(), j, 0);
  66       else
  67          swizzles[i] = LLVMGetUndef(LLVMInt32Type());
  68    }
  69
  70    unswizzled = LLVMBuildShuffleVector(builder, rgba,
  71                                        LLVMGetUndef(LLVMVectorType(LLVMFloatType(), 4)),
  72                                        LLVMConstVector(swizzles, 4), "");
  73
  74    normalized = FALSE;
  75    shift = 0;
  76    for (i = 0; i < 4; ++i) {
  77       unsigned bits = desc->channel[i].size;
  78
  79       if (desc->channel[i].type == UTIL_FORMAT_TYPE_VOID) {
  80          shifts[i] = LLVMGetUndef(LLVMInt32Type());
  81          scales[i] =  LLVMGetUndef(LLVMFloatType());
  82       }
  83       else {
  84          unsigned mask = (1 << bits) - 1;
  85
  86          assert(desc->channel[i].type == UTIL_FORMAT_TYPE_UNSIGNED);
  87          assert(bits < 32);
  88
  89          shifts[i] = LLVMConstInt(LLVMInt32Type(), shift, 0);
  90
  91          if (desc->channel[i].normalized) {
  92             scales[i] = LLVMConstReal(LLVMFloatType(), mask);
  93             normalized = TRUE;
  94          }
  95          else
  96             scales[i] =  LLVMConstReal(LLVMFloatType(), 1.0);
  97       }
  98
  99       shift += bits;
 100    }
 101
 102    if (normalized)
 103       scaled = LLVMBuildMul(builder, unswizzled, LLVMConstVector(scales, 4), "");
 104    else
 105       scaled = unswizzled;
 106
 107    casted = LLVMBuildFPToSI(builder, scaled, LLVMVectorType(LLVMInt32Type(), 4), "");
 108
 109    shifted = LLVMBuildShl(builder, casted, LLVMConstVector(shifts, 4), "");
 110
 111    /* Bitwise or all components */
 112    for (i = 0; i < 4; ++i) {
 113       if (desc->channel[i].type == UTIL_FORMAT_TYPE_UNSIGNED) {
 114          LLVMValueRef component = LLVMBuildExtractElement(builder, shifted, LLVMConstInt(LLVMInt32Type(), i, 0), "");
 115          if (packed)
 116             packed = LLVMBuildOr(builder, packed, component, "");
 117          else
 118             packed = component;
 119       }
 120    }
 121
 122    if (!packed)
 123       packed = LLVMGetUndef(LLVMInt32Type());
 124
 125    if (desc->block.bits < 32)
 126       packed = LLVMBuildTrunc(builder, packed, type, "");
 127
 128    return packed;
 129 }
 130