revectoring interrupt 128 0x80 in xinu

Question

i need your help, i want to change the way xinu (os) works so it will take over interrupt 128 and controll the SYS_CALL, for example, instead of calling to send(pid, msg) i will call to sys_call(SEND, pid, msg);. in initiali.c i've added

mapinit(INT80VEC,active80,INT80VEC);

and in the header i made i did

#ifndef hw4
#define hw4 256 //prevent rerun of the header file

#define INT80VEC 0x80
extern enum cmd{CHPRIO, GETPID, GETPRIO, KILL, RECEIVE, 
            RECVCLR, RESUME, SCOUNT, SCREATE, SDELETE, 
            SEND, SENDF, SENDN, SIGNAL, SIGNALN, SLEEP, 
            SLEEPT, SRESET, SUSPEND, WAIT, PCOUNT, PCREATE,last};
//last is just to find out how many arguments we have in the enum expression

extern SYSCALL sys_call(int sys_call_no, int parm1, int parm2);
extern int active80();

#endif

and the c file i made i got:

#include <kernel.h>
#include <conf.h>
#include "my.h"



SYSCALL sys_call(int sys_call_no, int parm1, int parm2){

int ps;
int temp;
disable(ps);
if(sys_call_no<0 ||sys_call_no>=last){
        restore(ps);
        return SYSERR;
}
asm{    mov ax,sys_call_no
        mov bx,parm1
        mov cx,parm2
        int 80h
        mov temp,ax
} 
restore(ps);
return temp;
}

INTPROC active80(){
int sys_call_no, parm1,parm2;
asm{    mov sys_call_no,ax
        mov parm1,bx
        mov parm2,cx
}
switch (sys_call_no) {
case CHPRIO:
    chprio(parm1,parm2);
    break;
case GETPID:
    getpid();
    break;
case GETPRIO:
    getprio(parm1);
    break;
case KILL:
    kill(parm1);
    break;
case RECEIVE:
    receive();
    break;
case RECVCLR:
    recvclr();
    break;
case RESUME:
    resume(parm1);
    break;
case SCOUNT:
    scount(parm1);
    break;
case SCREATE:
    screate(parm1);
    break;
case SDELETE:
    sdelete(parm1);
    break;
case SEND:
    send(parm1, parm2);
    break;
case SENDF:
    sendf(parm1, parm2);
    break;
case SENDN:
    sendn(parm1, parm2);
    break;
case SIGNAL:
    signal(parm1);
    break;
case SIGNALN:
    signaln(parm1,parm2);
    break;
case SLEEP:
    sleep(parm1);
    break;
case SLEEPT:
    sleept(parm1);
    break;
case SRESET:
    sreset(parm1,parm2);
    break;
case SUSPEND:
    suspend(parm1);
    break;
case WAIT:
    wait(parm1);
    break;
case PCOUNT:
    pcount(parm1);
    break;
case PCREATE:
    pcreate(parm1);
    break;
}
return OK;
}

something is not working... any ideas? thanks ahead!

Answer 1

You must restore your old isr using maprestore function.

Answer 2

well after serious digging around and read lots of material, the answer is: any proc has its own registers and stack, so one way is to create an array of procs and take their SP from pregs from the proctab and initialize the array with it, another possible is to create global variables that handled that, that is however much slower because registers are the fastest solution, but, it still will work