Return to nargs.c CVS log

Up to [CSRG BSD Unix] / 43BSDReno / pgrm / lisp / franz / 68k

Annotation of 43BSDReno/pgrm/lisp/franz/68k/nargs.c, revision 1.1.1.1

1.1       root        1: /* Copyright (c) 1982, Regents, University of California */
                      2: #define ADDQ 5
                      3: #define ADD 13
                      4: #define IMMED 074
                      5: /* These structures are here for looks, only */
                      6: struct add { short op:4, reg:3, mode:3, ea:6; } x;
                      7: struct addq { short op:4, data:3, size:3, ea:6; } y;
                      8: nargs(arg)
                      9: long arg; /* this is only here for address calculation */
                     10: {
                     11:        register long *a5;
                     12:        register handy;
                     13:        register char reg, mode, ea;
                     14: #define size mode
                     15: #define data reg
                     16: 
                     17:        a5 = (&arg) - 2; /* this points to old a6 */
                     18:        a5 = (long *) *a5; /* a5 now = my parents a6 */
                     19:        a5 = (long *) a5[1]; /* pick up return address into a5 */
                     20: 
                     21:        handy = * (short *)a5;
                     22:        ea = handy & 077; handy >>= 6;
                     23:        mode = handy & 07; handy >>= 3;
                     24:        reg = handy & 07; handy >>= 3;
                     25:        /* op = handy & 017; */
                     26:        switch(handy & 017) {
                     27:        case ADD:
                     28:                if(reg!=7)
                     29:                        return(0); /* this instruction doesn't adjust the sp */
                     30:                if(ea!=IMMED)
                     31:                        return(0); /* too hard to decode adjustment */
                     32:                handy = (long) (1 + (short *) a5);
                     33:                if(mode==03) {  /* addw #n,a7 */
                     34:                        handy = *(short *)handy;
                     35:                        return(handy >> 2);
                     36:                }
                     37:                if(mode==07) { /* addl #n,a7 */
                     38:                        handy = *(long *)handy;
                     39:                        return(handy >> 2);
                     40:                }
                     41:                else return(0); /* this was doing something to d7 */
                     42:        case ADDQ:
                     43:                if(ea!=017)
                     44:                        return(0); /* this doesn't adjust a7 */
                     45:                if(size!=02)
                     46:                        return(0); /* should complain -- we are doing
                     47:                                      addq[bw] something,a7 */
                     48:                switch(data) {
                     49:                case 0: return(2);
                     50:                case 4: return(1);
                     51:                }
                     52:        }
                     53:        return(0);
                     54: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.