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      1 //===-- NVPTXutil.cpp - Functions exported to CodeGen --*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file contains the functions that can be used in CodeGen.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "NVPTXutil.h"
     15 #include "NVPTX.h"
     16 
     17 using namespace llvm;
     18 
     19 namespace llvm {
     20 
     21 bool isParamLoad(const MachineInstr *MI)
     22 {
     23   if ((MI->getOpcode() != NVPTX::LD_i32_avar) &&
     24       (MI->getOpcode() != NVPTX::LD_i64_avar))
     25     return false;
     26   if (MI->getOperand(2).isImm() == false)
     27     return false;
     28   if (MI->getOperand(2).getImm() != NVPTX::PTXLdStInstCode::PARAM)
     29     return false;
     30   return true;
     31 }
     32 
     33 #define DATA_MASK     0x7f
     34 #define DIGIT_WIDTH   7
     35 #define MORE_BYTES    0x80
     36 
     37 static int encode_leb128(uint64_t val, int *nbytes,
     38                          char *space, int splen)
     39 {
     40   char *a;
     41   char *end = space + splen;
     42 
     43   a = space;
     44   do {
     45     unsigned char uc;
     46 
     47     if (a >= end)
     48       return 1;
     49     uc = val & DATA_MASK;
     50     val >>= DIGIT_WIDTH;
     51     if (val != 0)
     52       uc |= MORE_BYTES;
     53     *a = uc;
     54     a++;
     55   } while (val);
     56   *nbytes = a - space;
     57   return 0;
     58 }
     59 
     60 #undef DATA_MASK
     61 #undef DIGIT_WIDTH
     62 #undef MORE_BYTES
     63 
     64 uint64_t encode_leb128(const char *str)
     65 {
     66   union { uint64_t x; char a[8]; } temp64;
     67 
     68   temp64.x = 0;
     69 
     70   for (unsigned i=0,e=strlen(str); i!=e; ++i)
     71     temp64.a[i] = str[e-1-i];
     72 
     73   char encoded[16];
     74   int nbytes;
     75 
     76   int retval = encode_leb128(temp64.x, &nbytes, encoded, 16);
     77 
     78   (void)retval;
     79   assert(retval == 0 &&
     80          "Encoding to leb128 failed");
     81 
     82   assert(nbytes <= 8 &&
     83          "Cannot support register names with leb128 encoding > 8 bytes");
     84 
     85   temp64.x = 0;
     86   for (int i=0; i<nbytes; ++i)
     87     temp64.a[i] = encoded[i];
     88 
     89   return temp64.x;
     90 }
     91 
     92 } // end namespace llvm
     93