1 /* 2 * 2obj.c - identify and parse a 68020 object file 3 */ 4 #include <u.h> 5 #include <libc.h> 6 #include <bio.h> 7 #include <mach.h> 8 #include "68020/2.out.h" 9 #include "obj.h" 10 11 typedef struct Addr Addr; 12 struct Addr 13 { 14 char sym; 15 char flags; 16 }; 17 static Addr addr(Biobuf *); 18 static char type2char(int); 19 static void skip(Biobuf*, int); 20 21 int 22 _is2(char *t) 23 { 24 uchar *s = (uchar *)t; 25 26 return s[0] == (ANAME&0xff) /* aslo = ANAME */ 27 && s[1] == ((ANAME>>8)&0xff) /* ashi = ANAME */ 28 && s[2] == D_FILE /* type */ 29 && s[3] == 1 /* sym */ 30 && s[4] == '<'; /* name of file */ 31 } 32 33 int 34 _read2(Biobuf *bp, Prog *p) 35 { 36 int as, n, c; 37 Addr a; 38 39 as = Bgetc(bp); /* as(low) */ 40 if(as < 0) 41 return 0; 42 c = Bgetc(bp); /* as(high) */ 43 if(c < 0) 44 return 0; 45 as |= ((c & 0xff) << 8); 46 p->kind = aNone; 47 p->sig = 0; 48 if(as == ANAME || as == ASIGNAME){ 49 if(as == ASIGNAME){ 50 Bread(bp, &p->sig, 4); 51 p->sig = beswal(p->sig); 52 } 53 p->kind = aName; 54 p->type = type2char(Bgetc(bp)); /* type */ 55 p->sym = Bgetc(bp); /* sym */ 56 n = 0; 57 for(;;) { 58 as = Bgetc(bp); 59 if(as < 0) 60 return 0; 61 n++; 62 if(as == 0) 63 break; 64 } 65 p->id = malloc(n); 66 if(p->id == 0) 67 return 0; 68 Bseek(bp, -n, 1); 69 if(Bread(bp, p->id, n) != n) 70 return 0; 71 return 1; 72 } 73 if(as == ATEXT) 74 p->kind = aText; 75 else if(as == AGLOBL) 76 p->kind = aData; 77 skip(bp, 4); /*lineno: low, high, lowhigh, highigh*/ 78 a = addr(bp); 79 addr(bp); 80 if(!(a.flags & T_SYM)) 81 p->kind = aNone; 82 p->sym = a.sym; 83 return 1; 84 } 85 86 static Addr 87 addr(Biobuf *bp) 88 { 89 Addr a; 90 int t; 91 long off; 92 93 a.flags = Bgetc(bp); /* flags */ 94 a.sym = -1; 95 off = 0; 96 if(a.flags & T_FIELD) 97 skip(bp, 2); 98 if(a.flags & T_INDEX) 99 skip(bp, 7); 100 if(a.flags & T_OFFSET){ 101 off = Bgetc(bp); 102 off |= Bgetc(bp) << 8; 103 off |= Bgetc(bp) << 16; 104 off |= Bgetc(bp) << 24; 105 if(off < 0) 106 off = -off; 107 } 108 if(a.flags & T_SYM) 109 a.sym = Bgetc(bp); 110 if(a.flags & T_FCONST) 111 skip(bp, 8); 112 else if(a.flags & T_SCONST) 113 skip(bp, NSNAME); 114 else{ 115 t = Bgetc(bp); 116 if(a.flags & T_TYPE) 117 t |= Bgetc(bp) << 8; 118 t &= D_MASK; 119 if(a.sym > 0 && (t==D_PARAM || t==D_AUTO)) 120 _offset(a.sym, off); 121 } 122 return a; 123 } 124 125 static char 126 type2char(int t) 127 { 128 switch(t){ 129 case D_EXTERN: return 'U'; 130 case D_STATIC: return 'b'; 131 case D_AUTO: return 'a'; 132 case D_PARAM: return 'p'; 133 default: return UNKNOWN; 134 } 135 } 136 137 static void 138 skip(Biobuf *bp, int n) 139 { 140 while (n-- > 0) 141 Bgetc(bp); 142 } 143