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Annotation of 43BSDReno/pgrm/pascal/pdx/machine/setbp.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1980 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  */
        !             6: 
        !             7: #ifndef lint
        !             8: static char sccsid[] = "@(#)setbp.c    5.2 (Berkeley) 4/7/87";
        !             9: #endif not lint
        !            10: /*
        !            11:  * Breakpoint/machine interface.
        !            12:  */
        !            13: 
        !            14: #include "defs.h"
        !            15: #include <signal.h>
        !            16: #include "machine.h"
        !            17: #include "process.h"
        !            18: #include "main.h"
        !            19: #include "pxops.h"
        !            20: #include "process/process.rep"
        !            21: #include "process/pxinfo.h"
        !            22: 
        !            23: #define BP_OP          O_BPT           /* breakpoint trap */
        !            24: #define BP_ERRNO       SIGILL          /* signal received at a breakpoint */
        !            25: 
        !            26: /*
        !            27:  * Setting a breakpoint at a location consists of saving
        !            28:  * the half-word at the location and poking a BP_OP there.
        !            29:  *
        !            30:  * We save the locations and half-words on a list for use in unsetting.
        !            31:  */
        !            32: 
        !            33: typedef struct savelist SAVELIST;
        !            34: 
        !            35: struct savelist {
        !            36:        ADDRESS location;
        !            37:        short save;
        !            38:        short refcount;
        !            39:        SAVELIST *link;
        !            40: };
        !            41: 
        !            42: LOCAL SAVELIST *savelist;
        !            43: 
        !            44: /*
        !            45:  * Set a breakpoint at the given address.  Only save the half-word there
        !            46:  * if it's not already a breakpoint.
        !            47:  */
        !            48: 
        !            49: setbp(addr)
        !            50: ADDRESS addr;
        !            51: {
        !            52:        unsigned char w;
        !            53:        short save;
        !            54:        register SAVELIST *newsave, *s;
        !            55: 
        !            56:        if (option('b')) {
        !            57:                printf("setting breakpoint at %d\n", addr);
        !            58:                fflush(stdout);
        !            59:        }
        !            60:        for (s = savelist; s != NIL; s = s->link) {
        !            61:                if (s->location == addr) {
        !            62:                        s->refcount++;
        !            63:                        return;
        !            64:                }
        !            65:        }
        !            66:        iread(&save, addr, sizeof(save));
        !            67:        newsave = alloc(1, SAVELIST);
        !            68:        newsave->location = addr;
        !            69:        newsave->save = save;
        !            70:        newsave->refcount = 1;
        !            71:        newsave->link = savelist;
        !            72:        savelist = newsave;
        !            73:        w = BP_OP;
        !            74:        iwrite(&w, addr, sizeof(w));
        !            75: }
        !            76: 
        !            77: /*
        !            78:  * Unset a breakpoint; unfortunately we have to search the SAVELIST
        !            79:  * to find the saved value.  The assumption is that the SAVELIST will
        !            80:  * usually be quite small.
        !            81:  */
        !            82: 
        !            83: unsetbp(addr)
        !            84: ADDRESS addr;
        !            85: {
        !            86:        register SAVELIST *s, *prev;
        !            87: 
        !            88:        if (option('b')) {
        !            89:                printf("unsetting breakpoint at %d\n", addr);
        !            90:                fflush(stdout);
        !            91:        }
        !            92:        prev = NIL;
        !            93:        for (s = savelist; s != NIL; s = s->link) {
        !            94:                if (s->location == addr) {
        !            95:                        iwrite(&s->save, addr, sizeof(s->save));
        !            96:                        s->refcount--;
        !            97:                        if (s->refcount == 0) {
        !            98:                                if (prev == NIL) {
        !            99:                                        savelist = s->link;
        !           100:                                } else {
        !           101:                                        prev->link = s->link;
        !           102:                                }
        !           103:                                dispose(s);
        !           104:                        }
        !           105:                        return;
        !           106:                }
        !           107:                prev = s;
        !           108:        }
        !           109:        panic("unsetbp: couldn't find address %d", addr);
        !           110: }
        !           111: 
        !           112: /*
        !           113:  * Predicate to test if the reason the process stopped was because
        !           114:  * of a breakpoint.
        !           115:  */
        !           116: 
        !           117: BOOLEAN isbperr()
        !           118: {
        !           119:        register PROCESS *p;
        !           120: 
        !           121:        p = process;
        !           122:        return(p->status==STOPPED && p->signo==BP_ERRNO);
        !           123: }

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