Subversion Repositories planix.SVN

/*
 * 2obj.c - identify and parse a 68020 object file
 */
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <mach.h>
#include "68020/2.out.h"
#include "obj.h"

typedef struct Addr     Addr;
struct Addr
{
        char    sym;
        char    flags;
};
static Addr addr(Biobuf *);
static char type2char(int);
static void skip(Biobuf*, int);

int
_is2(char *t)
{
        uchar *s = (uchar *)t;

        return  s[0] == (ANAME&0xff)                    /* aslo = ANAME */
                && s[1] == ((ANAME>>8)&0xff)            /* ashi = ANAME */
                && s[2] == D_FILE                       /* type */
                && s[3] == 1                            /* sym */
                && s[4] == '<';                         /* name of file */
}

int
_read2(Biobuf *bp, Prog *p)
{
        int as, n, c;
        Addr a;

        as = Bgetc(bp);         /* as(low) */
        if(as < 0)
                return 0;
        c = Bgetc(bp);          /* as(high) */
        if(c < 0)
                return 0;
        as |= ((c & 0xff) << 8);
        p->kind = aNone;
        p->sig = 0;
        if(as == ANAME || as == ASIGNAME){
                if(as == ASIGNAME){
                        Bread(bp, &p->sig, 4);
                        p->sig = beswal(p->sig);
                }
                p->kind = aName;
                p->type = type2char(Bgetc(bp));         /* type */
                p->sym = Bgetc(bp);                     /* sym */
                n = 0;
                for(;;) {
                        as = Bgetc(bp);
                        if(as < 0)
                                return 0;
                        n++;
                        if(as == 0)
                                break;
                }
                p->id = malloc(n);
                if(p->id == 0)
                        return 0;
                Bseek(bp, -n, 1);
                if(Bread(bp, p->id, n) != n)
                        return 0;
                return 1;
        }
        if(as == ATEXT)
                p->kind = aText;
        else if(as == AGLOBL)
                p->kind = aData;
        skip(bp, 4);            /*lineno: low, high, lowhigh, highigh*/
        a = addr(bp);
        addr(bp);
        if(!(a.flags & T_SYM))
                p->kind = aNone;
        p->sym = a.sym;
        return 1;
}

static Addr
addr(Biobuf *bp)
{
        Addr a;
        int t;
        long off;

        a.flags = Bgetc(bp);                    /* flags */
        a.sym = -1;
        off = 0;
        if(a.flags & T_FIELD)
                skip(bp, 2);
        if(a.flags & T_INDEX)
                skip(bp, 7);
        if(a.flags & T_OFFSET){
                off = Bgetc(bp);
                off |= Bgetc(bp) << 8;
                off |= Bgetc(bp) << 16;
                off |= Bgetc(bp) << 24;
                if(off < 0)
                        off = -off;
        }
        if(a.flags & T_SYM)
                a.sym = Bgetc(bp);
        if(a.flags & T_FCONST)
                skip(bp, 8);
        else if(a.flags & T_SCONST)
                skip(bp, NSNAME);
        else{
                t = Bgetc(bp);
                if(a.flags & T_TYPE)
                        t |= Bgetc(bp) << 8;
                t &= D_MASK;
                if(a.sym > 0 && (t==D_PARAM || t==D_AUTO))
                        _offset(a.sym, off);
        }
        return a;
}

static char
type2char(int t)
{
        switch(t){
        case D_EXTERN:          return 'U';
        case D_STATIC:          return 'b';
        case D_AUTO:            return 'a';
        case D_PARAM:           return 'p';
        default:                return UNKNOWN;
        }
}

static void
skip(Biobuf *bp, int n)
{
        while (n-- > 0)
                Bgetc(bp);
}