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/*
* BK Id: SCCS/s.softemu8xx.c 1.8 05/17/01 18:14:22 cort
*/
/*
* 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>
#include <asm/processor.h>
/* 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 *)¤t->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, ¤t->thread.fpr[(instword>>11)&0x1f],
sizeof(double) );
break;
default:
retval = 1;
printk("Bad emulation %s/%d\n"
" NIP: %08x 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 = __va(pa);
printk("Kernel VA for NIP %x ", pa);
print_8xx_pte(current->mm,pa);
}
}
if (retval == 0)
regs->nip += 4;
return(retval);
}
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