sign_extension.cpp revision 12855:588919e0e4aa 
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20/*****************************************************************************
21
22  sign_extension.cpp --
23
24  Original Author: Philipp A. Hartmann, OFFIS, 2012-07-17
25
26 -----------------------------------------------------------------------------
27
28 This test demonatrates a bug in the sc_biguint constructor(?), where
29 construction from bit-wise expressions with "unsigned int" and sc_bigint
30 may lead to wrongly sign-extended values (at least on 32-bit machines) when
31 the destination size is bigger than the source size.
32
33 *****************************************************************************/
34
35#include <systemc>
36using sc_dt::sc_int;
37using sc_dt::sc_uint;
38using sc_dt::sc_bigint;
39using sc_dt::sc_biguint;
40using sc_dt::SC_BIN;
41
42#define DUMP_VAR( Var ) \
43  std::cout << #Var "=" << (Var).to_string(SC_BIN) << "\n"
44
45int sc_main(int, char*[])
46{
47
48    sc_int<31>     v_sc_int_31_min     = (1<<30); // 010...0 (31 bit)
49    sc_bigint<31>  v_sc_bigint_31_min  = (1<<30); // 010...0
50    unsigned int   v_uint_max          = ~0;      // 11....1 (32-bit)
51    sc_uint<32>    v_sc_uint32_max     = ~0;      // 11....1 (32-bit)
52    sc_biguint<32> v_sc_biguint_32_max = -1;      // 11....1 (32-bit)
53
54    DUMP_VAR( v_sc_int_31_min );
55    DUMP_VAR( v_sc_bigint_31_min );
56    DUMP_VAR( v_sc_uint32_max );
57    DUMP_VAR( v_sc_biguint_32_max );
58
59    sc_bigint<64> int31_uint         = (v_sc_int_31_min    & v_uint_max);
60    // the following expression yields 0b1....10...0 on 32-bit machines
61    sc_bigint<64> bigint31_uint      = (v_sc_bigint_31_min & v_uint_max);
62    sc_bigint<64> bigint31_uint32    = (v_sc_bigint_31_min & v_sc_uint32_max);
63    sc_bigint<64> bigint31_biguint32 = (v_sc_bigint_31_min & v_sc_biguint_32_max);
64
65    DUMP_VAR( v_sc_bigint_31_min & v_uint_max );
66    DUMP_VAR( v_sc_bigint_31_min & v_sc_biguint_32_max );
67
68    DUMP_VAR(int31_uint);
69    DUMP_VAR(bigint31_uint); // <--
70    DUMP_VAR(bigint31_uint32);
71    DUMP_VAR(bigint31_biguint32);
72
73    return 0;
74}
75
76