/*
* Handle the process of a GETTY.
*/
static void do_getty(char *tty, char *name, size_t len)
{
int ch;
char *np;
/*
* Clean up tty name.
*/
if (!strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)))
tty += 5;
/*
* Display prompt.
*/
ch = ' ';
*name = '\0';
while (ch != '\n') {
do_issue(tty);
np = name;
while ((ch = readch(tty)) != '\n') {
if (ch == CTL('U')) {
while (np > name) {
(void)write(1, "\b \b", 3);
np--;
}
continue;
}
if (np < name + len)
*np++ = ch;
}
*np = '\0';
if (*name == '\0')
ch = ' '; /* blank line typed! */
}
name[len - 1] = 0;
}
int Data_path (void)
{
register struct mem_wrd *memaddr;
register struct IR_FIELDS *ir;
register struct SIM_FLAGS *f;
int retval,retval_cmmu; /* return value */
unsigned int issue_latency = 0; /* max time to issue instr(s) */
if (ckbrkpts(IP, BRK_EXEC)) /* Check for breakpoint */
{
retval = -1;
return(retval);
}
retval_cmmu = 0;
if(usecmmu && (retval = cmmu_function1()))
return(retval);
if ((memaddr = getmemptr (IP, M_INSTR)) == 0)
return (exception(E_TCACC, "Code Access Bus Error"));
ir = &memaddr -> opcode;
f = ((ir->p) ? &ir->p->flgs: &simdata.flgs);
/* see if we can issue the instruction in this clock */
if ( (retval = test_issue( ir, f )) == -1 )
{
return ( retval );
}
else
{
Statistics (ir);
/* Issue the instruction to the appropriate FU */
do_issue();
issue_latency = f->is_latency;
issue_latency += retval;
prev_extime = issue_latency;
if(debugflag)
PPrintf(" after chk_SB : Dcmmutime = %d \n", Dcmmutime);
if (usecmmu)
cmmu_function2(ir);
/*
* The data from the source 1 register is put onto the
* source 1 bus, as an input to the ALU.
*/
m88000.S1bus = m88000.Regs[ir -> src1];
/*
* The data from the source 2 register, or an immediate
* value, is put on the source 2 bus, which is also an
* input to the ALU.
*/
if (!f -> imm_flags) /* if not immediate */
m88000.S2bus = m88000.Regs[ir -> src2];
else if (f -> imm_flags == i26bit)
m88000.S2bus = sext (opword (IP), 0, 26);
else if ((f -> imm_flags == i16bit) &&
((ir -> op < (unsigned)JSR) || (ir -> op > (unsigned)BCND)))
m88000.S2bus = uext (opword (IP), 0, 16);
else if ((f -> imm_flags == i16bit) &&
((ir -> op >= (unsigned)JSR) && (ir -> op <= (unsigned)BCND)))
m88000.S2bus = sext (opword (IP), 0, 16);
else if (f -> imm_flags == i10bit)
m88000.S2bus = uext (opword (IP), 0, 10);
else
{
Eprintf ("SYSTEM ERROR in dpath, funky sized immediate\n");
return(-1);
}
/*
* The instruction has been issued and the busses have
* been driven. Now execute the instruction.
*/
if( retval = execute(ir, f, memaddr) ) return(retval);
if (usecmmu && debugflag)
PPrintf(" Dcmmutime (total after store) = %d \n",Dcmmutime);
/*
* Adjust the program counter
*/
killtime ( issue_latency );
if ( retval = Pc(memaddr, ir, f) )
return ( retval );
}
return ( retval );
}
