Logo Search packages:      
Sourcecode: linux version File versions  Download package

softemu8xx.c

/*
 * Software emulation of some PPC instructions for the 8xx core.
 *
 * Copyright (C) 1998 Dan Malek (dmalek@jlc.net)
 *
 * Software floating emuation for the MPC8xx processor.  I did this mostly
 * because it was easier than trying to get the libraries compiled for
 * software floating point.  The goal is still to get the libraries done,
 * but I lost patience and needed some hacks to at least get init and
 * shells running.  The first problem is the setjmp/longjmp that save
 * and restore the floating point registers.
 *
 * For this emulation, our working registers are found on the register
 * save area.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>

#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>

extern void
print_8xx_pte(struct mm_struct *mm, unsigned long addr);
extern int
get_8xx_pte(struct mm_struct *mm, unsigned long addr);

/* Eventually we may need a look-up table, but this works for now.
*/
#define LFS 48
#define LFD 50
#define LFDU      51
#define STFD      54
#define STFDU     55
#define FMR 63

/*
 * We return 0 on success, 1 on unimplemented instruction, and EFAULT
 * if a load/store faulted.
 */
int
Soft_emulate_8xx(struct pt_regs *regs)
{
      uint  inst, instword;
      uint  flreg, idxreg, disp;
      uint  retval;
      signed short sdisp;
      uint  *ea, *ip;

      retval = 0;

      instword = *((uint *)regs->nip);
      inst = instword >> 26;

      flreg = (instword >> 21) & 0x1f;
      idxreg = (instword >> 16) & 0x1f;
      disp = instword & 0xffff;

      ea = (uint *)(regs->gpr[idxreg] + disp);
      ip = (uint *)&current->thread.fpr[flreg];

      switch ( inst )
      {
      case LFD:
            /* this is a 16 bit quantity that is sign extended
             * so use a signed short here -- Cort
             */
            sdisp = (instword & 0xffff);
            ea = (uint *)(regs->gpr[idxreg] + sdisp);
            if (copy_from_user(ip, ea, sizeof(double)))
                  retval = -EFAULT;
            break;
            
      case LFDU:
            if (copy_from_user(ip, ea, sizeof(double)))
                  retval = -EFAULT;
            else
                  regs->gpr[idxreg] = (uint)ea;
            break;
      case LFS:
            sdisp = (instword & 0xffff);
            ea = (uint *)(regs->gpr[idxreg] + sdisp);
            if (copy_from_user(ip, ea, sizeof(float)))
                  retval = -EFAULT;
            break;
      case STFD:
            /* this is a 16 bit quantity that is sign extended
             * so use a signed short here -- Cort
             */
            sdisp = (instword & 0xffff);
            ea = (uint *)(regs->gpr[idxreg] + sdisp);
            if (copy_to_user(ea, ip, sizeof(double)))
                  retval = -EFAULT;
            break;

      case STFDU:
            if (copy_to_user(ea, ip, sizeof(double)))
                  retval = -EFAULT;
            else
                  regs->gpr[idxreg] = (uint)ea;
            break;
      case FMR:
            /* assume this is a fp move -- Cort */
            memcpy( ip, &current->thread.fpr[(instword>>11)&0x1f],
                  sizeof(double) );
            break;
      default:
            retval = 1;
            printk("Bad emulation %s/%d\n"
                   " NIP: %08lx instruction: %08x opcode: %x "
                   "A: %x B: %x C: %x code: %x rc: %x\n",
                   current->comm,current->pid,
                   regs->nip,
                   instword,inst,
                   (instword>>16)&0x1f,
                   (instword>>11)&0x1f,
                   (instword>>6)&0x1f,
                   (instword>>1)&0x3ff,
                   instword&1);
            {
                  int pa;
                  print_8xx_pte(current->mm,regs->nip);
                  pa = get_8xx_pte(current->mm,regs->nip) & PAGE_MASK;
                  pa |= (regs->nip & ~PAGE_MASK);
                  pa = (unsigned long)__va(pa);
                  printk("Kernel VA for NIP %x ", pa);
                  print_8xx_pte(current->mm,pa);
            }
            
      }

      if (retval == 0)
            regs->nip += 4;
      return(retval);
}


Generated by  Doxygen 1.6.0   Back to index