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1 #include <stdint.h>
2 #include <stdio.h>
3 
4 typedef struct {
5    uint64_t high;
6    uint64_t low;
7 } __attribute__((aligned(16))) quad_word;
8 
9 
10 /* CDSG needs quad-word alignment */
11 quad_word _op1, _op2, _op3;
12 
13 void
test(quad_word op1_init,quad_word op2_init,quad_word op3_init,int expected_cc)14 test(quad_word op1_init, quad_word op2_init, quad_word op3_init,
15      int expected_cc)
16 {
17    quad_word op1_before, op2_before, op3_before;
18    int cc = 1 - expected_cc;
19 
20    _op1 = op1_init;
21    _op2 = op2_init;
22    _op3 = op3_init;
23 
24    op1_before = _op1;
25    op2_before = _op2;
26    op3_before = _op3;
27 
28    printf("before op1 = (%#lx, %#lx)\n", _op1.high, _op1.low);
29    printf("before op2 = (%#lx, %#lx)\n", _op2.high, _op2.low);
30    printf("before op3 = (%#lx, %#lx)\n", _op3.high, _op3.low);
31 
32    __asm__ volatile (
33                      "lmg     %%r0,%%r1,%1\n\t"
34                      "lmg     %%r2,%%r3,%3\n\t"
35                      "cdsg    %%r0,%%r2,%2\n\t"  //  cdsg 1st,3rd,2nd
36                      "stmg    %%r0,%%r1,%1\n"    // store r0,r1 to _op1
37                      "stmg    %%r2,%%r3,%3\n"    // store r2,r3 to _op3
38                      "ipm     %0\n\t"
39                      "srl     %0,28\n\t"
40                      : "=d" (cc), "+QS" (_op1), "+QS" (_op2), "+QS" (_op3)
41                      :
42                      : "r0", "r1", "r2", "r3", "cc");
43 
44    printf("after  op1 = (%#lx, %#lx)\n", _op1.high, _op1.low);
45    printf("after  op2 = (%#lx, %#lx)\n", _op2.high, _op2.low);
46    printf("after  op3 = (%#lx, %#lx)\n", _op3.high, _op3.low);
47    printf("cc = %d\n", cc);
48 
49    if (cc != expected_cc) {
50       printf("condition code is incorrect\n");
51    }
52 
53    // _op3 never changes
54    if (_op3.low != op3_before.low || _op3.high != op3_before.high) {
55       printf("operand #3 modified\n");
56    }
57 
58    if (expected_cc == 0) {
59       // 3rd operand stored at 2nd operand location
60 
61       // _op1 did not change
62       if (_op1.low != op1_before.low || _op1.high != op1_before.high) {
63          printf("operand #1 modified\n");
64       }
65       if (_op2.high != _op3.high || _op2.low != _op3.low) {
66          printf("operand #2 incorrect\n");
67       }
68    } else {
69       // 2nd operand stored at 1st operand location
70 
71       // _op2 did not change
72       if (_op2.low != op2_before.low || _op2.high != op2_before.high) {
73          printf("operand #2 modified\n");
74       }
75 
76       if (_op1.high != _op2.high || _op1.low != _op2.low) {
77          printf("operand #1 incorrect\n");
78       }
79    }
80 }
81 
main()82 int main ()
83 {
84    quad_word op1, op2, op3;
85 
86    // op1 == op2
87    op1.high = 0x0011223344556677ull;
88    op1.low  = 0x8899aabbccddeeffull;
89    op2 = op1;
90    op3.high = op3.low = 0xdeadbeefdeadbabeull;
91    test(op1, op2, op3, 0);
92 
93    // op1 != op2 (only MSB differs)
94    op1.high = 0x8000000000000000ull;
95    op1.low  = 0x0000000000000000ull;
96    op2.high = 0;
97    op2.low  = 1;
98    op3.high = op3.low = 0xdeadbeefdeadbabeull;
99    test(op1, op2, op3, 1);
100 
101    // op1 != op2 (only LSB differs)
102    op1.high = 0x0000000000000000ull;
103    op1.low  = 0x0000000000000001ull;
104    op2.high = 1;
105    op2.low  = 0;
106    op3.high = op3.low = 0xdeadbeefdeadbabeull;
107    test(op1, op2, op3, 1);
108 
109    return 0;
110 }
111