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Annotation of lucent/sys/src/boot/pc/f002811, revision 1.1

1.1     ! root        1: #include       "u.h"
        !             2: #include       "lib.h"
        !             3: #include       "mem.h"
        !             4: #include       "dat.h"
        !             5: #include       "fns.h"
        !             6: 
        !             7: /*
        !             8:  *  read in a segment
        !             9:  */
        !            10: static long
        !            11: readseg(int dev, long (*read)(int, void*, int), long len, long addr)
        !            12: {
        !            13:        char *a;
        !            14:        long n, sofar;
        !            15: 
        !            16:        a = (char *)addr;
        !            17:        for(sofar = 0; sofar < len; sofar += n){
        !            18:                n = 8*1024;
        !            19:                if(len - sofar < n)
        !            20:                        n = len - sofar;
        !            21:                n = (*read)(dev, a + sofar, n);
        !            22:                if(n <= 0)
        !            23:                        break;
        !            24:                print(".");
        !            25:        }
        !            26:        return sofar;
        !            27: }
        !            28: 
        !            29: /*
        !            30:  *  boot
        !            31:  */
        !            32: int
        !            33: plan9boot(int dev, long (*seek)(int, long), long (*read)(int, void*, int))
        !            34: {
        !            35:        long n;
        !            36:        long addr;
        !            37:        void (*b)(void);
        !            38:        Exec *ep;
        !            39: 
        !            40:        if((*seek)(dev, 0) < 0)
        !            41:                return -1;
        !            42: 
        !            43:        /*
        !            44:         *  read header
        !            45:         */
        !            46:        ep = (Exec *) ialloc(sizeof(Exec), 0);
        !            47:        n = sizeof(Exec);
        !            48:        if(readseg(dev, read, n, (ulong) ep) != n){
        !            49:                print("premature EOF\n");
        !            50:                return -1;
        !            51:        }
        !            52:        if(GLLONG(ep->magic) != I_MAGIC){
        !            53:                print("bad magic 0x%lux not a plan 9 executable!\n", GLLONG(ep->magic));
        !            54:                return -1;
        !            55:        }
        !            56: 
        !            57:        /*
        !            58:         *  read text
        !            59:         */
        !            60:        addr = PADDR(GLLONG(ep->entry));
        !            61:        n = GLLONG(ep->text);
        !            62:        print("%d", n);
        !            63:        if(readseg(dev, read, n, addr) != n){
        !            64:                print("premature EOF\n");
        !            65:                return -1;
        !            66:        }
        !            67: 
        !            68:        /*
        !            69:         *  read data (starts at first page after kernel)
        !            70:         */
        !            71:        addr = PGROUND(addr+n);
        !            72:        n = GLLONG(ep->data);
        !            73:        print("+%d", n);
        !            74:        if(readseg(dev, read, n, addr) != n){
        !            75:                print("premature EOF\n");
        !            76:                return -1;
        !            77:        }
        !            78: 
        !            79:        /*
        !            80:         *  bss and entry point
        !            81:         */
        !            82:        print("+%d\nstart at 0x%lux\n", GLLONG(ep->bss), GLLONG(ep->entry));
        !            83: 
        !            84:        /*
        !            85:         *  Go to new code. It's up to the program to get its PC relocated to
        !            86:         *  the right place.
        !            87:         */
        !            88:        b = (void (*)(void))(PADDR(GLLONG(ep->entry)));
        !            89:        (*b)();
        !            90:        return 0;
        !            91: }

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