1 extern void abort (void);
2
3 typedef struct PgHdr PgHdr;
4 typedef unsigned char u8;
5 struct PgHdr {
6 int y;
7 struct {
8 unsigned int pgno;
9 PgHdr *pNextHash, *pPrevHash;
10 PgHdr *pNextFree, *pPrevFree;
11 PgHdr *pNextAll;
12 u8 inJournal;
13 short int nRef;
14 PgHdr *pDirty, *pPrevDirty;
15 unsigned int notUsed;
16 } x;
17 };
18 PgHdr **xx;
19 volatile int vx;
merge_pagelist(PgHdr * pA,PgHdr * pB)20 static inline PgHdr *merge_pagelist(PgHdr *pA, PgHdr *pB)
21 {
22 PgHdr result;
23 PgHdr *pTail;
24 xx = &result.x.pDirty;
25 pTail = &result;
26 while( pA && pB ){
27 if( pA->x.pgno<pB->x.pgno ){
28 pTail->x.pDirty = pA;
29 pTail = pA;
30 pA = pA->x.pDirty;
31 }else{
32 pTail->x.pDirty = pB;
33 pTail = pB;
34 pB = pB->x.pDirty;
35 }
36 vx = (*xx)->y;
37 }
38 if( pA ){
39 pTail->x.pDirty = pA;
40 }else if( pB ){
41 pTail->x.pDirty = pB;
42 }else{
43 pTail->x.pDirty = 0;
44 }
45 return result.x.pDirty;
46 }
47
sort_pagelist(PgHdr * pIn)48 PgHdr * __attribute__((noinline)) sort_pagelist(PgHdr *pIn)
49 {
50 PgHdr *a[25], *p;
51 int i;
52 __builtin_memset (a, 0, sizeof (a));
53 while( pIn ){
54 p = pIn;
55 pIn = p->x.pDirty;
56 p->x.pDirty = 0;
57 for(i=0; i<25 -1; i++){
58 if( a[i]==0 ){
59 a[i] = p;
60 break;
61 }else{
62 p = merge_pagelist(a[i], p);
63 a[i] = 0;
64 a[i] = 0;
65 }
66 }
67 if( i==25 -1 ){
68 a[i] = merge_pagelist(a[i], p);
69 }
70 }
71 p = a[0];
72 for(i=1; i<25; i++){
73 p = merge_pagelist (p, a[i]);
74 }
75 return p;
76 }
77
main()78 int main()
79 {
80 PgHdr a[5];
81 PgHdr *p;
82 a[0].x.pgno = 5;
83 a[0].x.pDirty = &a[1];
84 a[1].x.pgno = 4;
85 a[1].x.pDirty = &a[2];
86 a[2].x.pgno = 1;
87 a[2].x.pDirty = &a[3];
88 a[3].x.pgno = 3;
89 a[3].x.pDirty = 0;
90 p = sort_pagelist (&a[0]);
91 if (p->x.pDirty == p)
92 abort ();
93 return 0;
94 }
95