xinu: Desktop/xinu_mips-1.0.2.tar/xinu_mips-1.0.2/system/create.c Source File Main Page Data Structures Files Desktop/xinu_mips-1.0.2.tar/xinu_mips-1.0.2/system/create.cGo to the documentation of this file. 00001
00007 /* Embedded XINU, Copyright (C) 2007. All rights reserved. */
00008
00009 #include
00010 #include
00011 #include
00012 #include
00013 #include
00014 #include
00015
00016 local newpid(void);
00017 void userret(void);
00018
00028 syscall create(void *procaddr, ulong ssize, ushort priority,
00029 char *name, ulong nargs, ...)
00030 {
00031 ulong *saddr; /* stack address */
00032 ulong *savargs; /* pointer to arg saving region */
00033 ulong pid; /* stores new process id */
00034 pcb *ppcb; /* pointer to proc control blk */
00035 ulong i;
00036 va_list ap; /* points to list of var args */
00037 ulong pads; /* padding entries in record. */
00038 void INITRET(void);
00039
00040 if (ssize < MINSTK) ssize = MINSTK;
00041 ssize = (ulong)roundew(ssize); /* round up to even boundary */
00042 saddr = (ulong *)getmem(ssize); /* allocate new stack and pid */
00043 pid = newpid();
00044 /* a little error checking */
00045 if ( (((ulong *)SYSERR) == saddr) || (SYSERR == pid) )
00046 { return SYSERR; }
00047
00048 numproc++;
00049 ppcb = &proctab[ pid ];
00050 /* setup PCB entry for new proc */
00051 ppcb->state = PRSUSP;
00052 ppcb->prio = priority;
00053 ppcb->stkbase = saddr;
00054 saddr = (ulong *)(((ulong)saddr) + ssize - sizeof(ulong));
00055 ppcb->stklen = ((ulong)saddr) - (ulong)ppcb->stkbase;
00056 ppcb->stkptr = saddr;
00057 strncpy(ppcb->name, name, PNMLEN);
00058 ppcb->parent = (ushort)getpid();
00059
00060 /* Initialize stack with accounting block. */
00061 *saddr = STACKMAGIC;
00062 *--saddr = pid;
00063 *--saddr = ppcb->stklen;
00064 *--saddr = (ulong)ppcb->stkbase;
00065
00066 if (0 == nargs)
00067 { pads = 4; }
00068 else if (0 == (nargs % 4)) /* Must pad record size to */
00069 { pads = 0; } /* multiple of native memory */
00070 else /* transfer size. */
00071 { pads = 4 - (nargs % 4); }
00072
00073 for (i = 0; i < pads; i++) { *--saddr = 0; }
00074 /* Reserve space for all args. */
00075 for (i = nargs ; i > 0 ; i--) { *--saddr = 0; }
00076 savargs = saddr;
00077
00078 /* Build the context record as expected by ctxsw. */
00079 /* Clear room for saved state. */
00080 for (i = (CONTEXT_WORDS); i > 0; i--) { *--saddr = 0; }
00081 ppcb->stkptr = saddr;
00082 /* Address of proc entry point */
00083 saddr[(CONTEXT_WORDS) - 1] = (ulong)procaddr;
00084 /* Return Address value */
00085 saddr[(CONTEXT_WORDS) - 2] = (ulong)INITRET;
00086
00087 /* Place arguments into activation records. */
00088 va_start(ap, nargs);
00089 for (i = 0; i < nargs; i++)
00090 { savargs[i] = va_arg(ap, ulong); }
00091 va_end(ap);
00092
00093 return pid;
00094 }
00095
00100 local newpid(void)
00101 {
00102 int pid; /* process id to return */
00103 static int nextpid = 0;
00104
00105 for (pid = 0 ; pid < NPROC ; pid++)
00106 { /* check all NPROC slots */
00107 nextpid = (nextpid + 1) % NPROC;
00108 if (PRFREE == proctab[nextpid].state)
00109 { return nextpid; }
00110 }
00111 return SYSERR;
00112 }
00113
00117 void userret(void)
00118 {
00119 kill( getpid() );
00120 }
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