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/*
 * This module contains the PowerPC interrupt fielders
 * set of code at specific locations, based on function
 */

#include <linux/sys.h>
#include "ppc_asm.tmpl"

/* Keep track of low-level exceptions - rather crude, but informative */        
#define STATS

/*
 * Increment a [64 bit] statistic counter
 * Uses R2, R3
 */
#define BUMP(ctr) \
        lis     r2,ctr@h; \
        ori     r2,r2,ctr@l; \
        lwz     r3,4(r2); \
        addic   r3,r3,1; \
        stw     r3,4(r2); \
        lwz     r3,0(r2); \
        addze   r3,r3; \
        stw     r3,0(r2)

/* This instruction is not implemented on the PPC 603 */
#define tlbia \
        li      r4,64; \
        mtspr   CTR,r4; \
        li      r4,0; \
0:      tlbie   r4; \
        addi    r4,r4,0x1000; \
        bdnz    0b
        
_TEXT()

/*
 * Disable interrupts
 *      rc = _disable_interrupts()
 */
_GLOBAL(_disable_interrupts)
        mfmsr   r0              /* Get current interrupt state */
        rlwinm  r3,r0,16+1,32-1,31      /* Extract old value of 'EE' */
        li      r4,0            /* Need [unsigned] value of MSR_EE */
        ori     r4,r4,MSR_EE    /* Set to turn off bit */
        andc    r0,r0,r4        /* Clears bit in (r4) */
        sync                    /* Some chip revs have problems here... */
        mtmsr   r0              /* Update machine state */
        blr                     /* Done */

/*
 * Enable interrupts
 *      _enable_interrupts(int state)
 * turns on interrupts if state = 1.
 */
_GLOBAL(_enable_interrupts)
        mfmsr   r0              /* Get current state */
        rlwimi  r0,r3,16-1,32-16,32-16  /* Insert bit */
        sync                    /* Some chip revs have problems here... */
        mtmsr   r0              /* Update machine state */
        blr

/*
 * Get 'flags' (aka machine status register)
 *      __save_flags(long *ptr)
 */
_GLOBAL(__save_flags)
        mfmsr   r0              /* Get current state */
        stw     r0,0(r3)
        mr      r3,r0
        blr

/*
 * Restore 'flags'
 *      __restore_flags(long val)
 */
_GLOBAL(__restore_flags)
        sync                    /* Some chip revs have problems here... */
        mtmsr   r3
        isync
        blr

/*
 * Disable interrupts - like an 80x86
 *      cli()
 */
_GLOBAL(cli)
        mfmsr   r0              /* Get current interrupt state */
        rlwinm  r3,r0,16+1,32-1,31      /* Extract old value of 'EE' */
        li      r4,0            /* Need [unsigned] value of MSR_EE */
        ori     r4,r4,MSR_EE    /* Set to turn off bit */
        andc    r0,r0,r4        /* Clears bit in (r4) */
        sync                    /* Some chip revs have problems here... */
        mtmsr   r0              /* Update machine state */
        blr                     /* Done */

/*
 * Enable interrupts - like an 80x86
 *      sti()
 */
_GLOBAL(sti)
        mfmsr   r0              /* Get current state */
        ori     r0,r0,MSR_EE    /* Turn on 'EE' bit */
        sync                    /* Some chip revs have problems here... */
        mtmsr   r0              /* Update machine state */
        blr

/*
 * Flush MMU TLB
 */
_GLOBAL(_tlbia)
        tlbia
        BUMP(__TLBIAs)
        blr     

/*
 * Flush MMU TLB for a particular address
 */
_GLOBAL(_tlbie)
        tlbie   r3
        BUMP(__TLBIEs)
        blr

/*
 * Fetch the current SR register
 *   get_SR(int index)
 */
_GLOBAL(get_SR)
        mfsrin  r3,r3
        blr     

/*
 * Atomic [test&set] exchange
 *
 *      void *xchg_u32(void *ptr, unsigned long val)
 * Changes the memory location '*ptr' to be val and returns
 * the previous value stored there.
 */
_GLOBAL(xchg_u32)
        mr      r5,r3           /* Save pointer */
10:     lwarx   r3,0,r5         /* Fetch old value & reserve */
        stwcx.  r4,0,r5         /* Update with new value */
        bne-    10b             /* Retry if "reservation" (i.e. lock) lost */
        blr

/*
 * Atomic add/sub/inc/dec operations
 *
 * void atomic_add(int c, int *v)
 * void atomic_sub(int c, int *v)
 * void atomic_inc(int *v)
 * void atomic_dec(int *v)
 * void atomic_dec_and_test(int *v)
 */
_GLOBAL(atomic_add)
10:     lwarx   r5,0,r4         /* Fetch old value & reserve */
        add     r5,r5,r3        /* Perform 'add' operation */
        stwcx.  r5,0,r4         /* Update with new value */
        bne-    10b             /* Retry if "reservation" (i.e. lock) lost */
        blr
_GLOBAL(atomic_sub)
10:     lwarx   r5,0,r4         /* Fetch old value & reserve */
        sub     r5,r5,r3        /* Perform 'add' operation */
        stwcx.  r5,0,r4         /* Update with new value */
        bne-    10b             /* Retry if "reservation" (i.e. lock) lost */
        blr
_GLOBAL(atomic_inc)
10:     lwarx   r5,0,r3         /* Fetch old value & reserve */
        addi    r5,r5,1         /* Perform 'add' operation */
        stwcx.  r5,0,r3         /* Update with new value */
        bne-    10b             /* Retry if "reservation" (i.e. lock) lost */
        blr
_GLOBAL(atomic_dec)
10:     lwarx   r5,0,r3         /* Fetch old value & reserve */
        subi    r5,r5,1         /* Perform 'add' operation */
        stwcx.  r5,0,r3         /* Update with new value */
        bne-    10b             /* Retry if "reservation" (i.e. lock) lost */
        blr
_GLOBAL(atomic_dec_and_test)
10:     lwarx   r5,0,r3         /* Fetch old value & reserve */
        subi    r5,r5,1         /* Perform 'add' operation */
        stwcx.  r5,0,r3         /* Update with new value */
        bne-    10b             /* Retry if "reservation" (i.e. lock) lost */
        cmpi    0,r5,0          /* Return 'true' IFF 0 */
        bne     15f
        li      r3,1
        blr
15:     li      r3,0
        blr     
        

/*
 * Delay for a specific # of "loops"
 *      __delay(int loops)
 */
_GLOBAL(__delay)
        mtctr   r3
00:     addi    r3,r3,0         /* NOP */
        bdnz    00b
        blr

/*
 * Delay for a number of microseconds
 *      udelay(int usecs)
 */
_GLOBAL(udelay)
00:     li      r0,86   /* Instructions / microsecond? */
        mtctr   r0
10:     addi    r0,r0,0 /* NOP */
        bdnz    10b
        subic.  r3,r3,1
        bne     00b
        blr

/*
 * Atomically increment [intr_count]
 */
_GLOBAL(start_bh_atomic)
        lis     r3,intr_count@h
        ori     r3,r3,intr_count@l
10:     lwarx   r4,0,r3
        addi    r4,r4,1
        stwcx.  r4,0,r3
        bne-    10b
        blr

/*
 * Atomically decrement [intr_count]
 */
_GLOBAL(end_bh_atomic)
        lis     r3,intr_count@h
        ori     r3,r3,intr_count@l
10:     lwarx   r4,0,r3
        subic   r4,r4,1
        stwcx.  r4,0,r3
        bne-    10b
        blr

/*
 * I/O string operations
 *
 * insw(port, buf, len)
 * outsw(port, buf, len)
 */
_GLOBAL(_insw)
        mtctr   r5
        subi    r4,r4,2
00:     lhbrx   r5,0,r3
        sthu    r5,2(r4)
        bdnz    00b
        blr

_GLOBAL(_outsw)
        mtctr   r5
        subi    r4,r4,2
00:     lhzu    r5,2(r4)
        sthbrx  r5,0,r3 
        bdnz    00b
        blr     

#if 0   
/*
 *extern inline int find_first_zero_bit(void * vaddr, unsigned size)
 *{
 *      unsigned long res;
 *      unsigned long *p;
 *      unsigned long *addr = vaddr;
 *
 *      if (!size)
 *              return 0;
 *      __asm__ __volatile__ ("    moveq #-1,d0\n\t"
 *                            "1:"
 *                            "    cmpl  %1@+,d0\n\t"
 *                            "    bne   2f\n\t"
 *                            "    subql #1,%0\n\t"
 *                            "    bne   1b\n\t"
 *                            "    bra   5f\n\t"
 *                            "2:"
 *                            "    movel %1@-,d0\n\t"
 *                            "    notl  d0\n\t"
 *                            "    bfffo d0{#0,#0},%0\n\t"
 *                            "5:"
 *                            : "=d" (res), "=a" (p)
 *                            : "0" ((size + 31) >> 5), "1" (addr)
 *                            : "d0");
 *      return ((p - addr) << 5) + res;
 *}
 */
_GLOBAL(find_first_zero_bit)
        li      r5,0            /* bit # */
        subi    r3,r3,4         /* Adjust pointer for auto-increment */
00:     lwzu    r0,4(r3)        /* Get next word */
        not.    r7,r0           /* Complement to find ones */
        beq     10f             /* Jump if all ones */
02:     andi.   r7,r0,1         /* Check low-order bit */
        beq     20f             /* All done when zero found */
        srawi   r0,r0,1
        addi    r5,r5,1
        b       02b
10:     addi    r5,r5,32        /* Update bit # */
        subic.  r4,r4,32        /* Any more? */
        bgt     00b
20:     mr      r3,r5           /* Compute result */    
        blr
 
/*
 *static inline int find_next_zero_bit (void *vaddr, int size,
 *                                    int offset)
 *{
 *      unsigned long *addr = vaddr;
 *      unsigned long *p = addr + (offset >> 5);
 *      int set = 0, bit = offset & 31, res;
 *
 *      if (bit) {
 *              // Look for zero in first longword 
 *              __asm__("bfffo %1{#0,#0},%0"
 *                      : "=d" (set)
 *                      : "d" (~*p << bit));
 *              if (set < (32 - bit))
 *                      return set + offset;
 *                set = 32 - bit;
 *              p++;
 *      }
 *      // No zero yet, search remaining full bytes for a zero 
 *      res = find_first_zero_bit (p, size - 32 * (p - addr));
 *      return (offset + set + res);
 *}
 */
_GLOBAL(find_next_zero_bit)
        addi    r5,r5,1         /* bump offset to start */
        srawi   r6,r5,5         /* word offset */
        add     r6,r6,r6        /* byte offset */
        add     r6,r6,r6        /* byte offset */
        add     r3,r3,r6        /* compute byte position */
        sub     r4,r4,r5        /* adjust size by starting index */
        andi.   r0,r5,0x1F      /* offset in current word? */
        beq     10f             /* at start of word */
        lwz     r0,0(r3)        /* get word */
        sraw    r0,r0,r5        /* shift right */
        not.    r7,r0
        beq     07f             /* jump if only ones remain */
05:     andi.   r7,r0,1         /* found zero? */
        beq     90f             /* yes - all done */
        srawi   r0,r0,1
        addi    r5,r5,1
        b       05b
07:     andi.   r6,r5,0x1F
        subfic  r0,r6,32
        add     r5,r5,r0
        sub     r4,r4,r0
        b       20f
10:     subi    r3,r3,4         /* Adjust pointer for auto-increment */
20:     lwzu    r0,4(r3)        /* Get next word */
        not.    r7,r0           /* Complement to find ones */
        beq     40f             /* Jump if all ones */
30:     andi.   r7,r0,1         /* Check low-order bit */
        beq     90f             /* All done when zero found */
        srawi   r0,r0,1
        addi    r5,r5,1
        b       30b
40:     addi    r5,r5,32        /* Update bit # */
        subic.  r4,r4,32        /* Any more? */
        bgt     20b
90:     mr      r3,r5           /* Compute result */    
        blr
#endif
 
/*
 *
 * ffz = Find First Zero in word. Undefined if no zero exists,
 * so code should check against ~0UL first..
 *
 *extern inline unsigned long ffz(unsigned long word)
 *{
 *      __asm__ __volatile__ ("bfffo %1{#0,#0},%0"
 *                            : "=d" (word)
 *                            : "d" (~(word)));
 *      return word;
 *}
 */
_GLOBAL(ffz)
        mr      r4,r3
        li      r3,0
10:     andi.   r0,r4,1         /* Find the zero we know is there */
        srawi   r4,r4,1
        beq     90f
        addi    r3,r3,1
        b       10b
90:     blr

/*
 * Extended precision shifts
 *
 * R3/R4 has 64 bit value
 * R5    has shift count
 * result in R3/R4
 *
 *  ashrdi3:     XXXYYY/ZZZAAA -> SSSXXX/YYYZZZ
 *  ashldi3:     XXXYYY/ZZZAAA -> YYYZZZ/AAA000
 */
_GLOBAL(__ashrdi3)
        li      r6,32
        sub     r6,r6,r5
        slw     r7,r3,r6        /* isolate YYY */
        srw     r4,r4,r5        /* isolate ZZZ */
        or      r4,r4,r7        /* YYYZZZ */
        sraw    r3,r3,r5        /* SSSXXX */
        blr
        
_GLOBAL(__ashldi3)
        li      r6,32
        sub     r6,r6,r5
        srw     r7,r4,r6        /* isolate ZZZ */
        slw     r4,r4,r5        /* AAA000 */
        slw     r3,r3,r5        /* YYY--- */
        or      r3,r3,r7        /* YYYZZZ */
        blr
        
_GLOBAL(abort)
        .long   0

_GLOBAL(bzero)
#define bufp r3
#define len  r4
#define pat  r5
/* R3 has buffer */
/* R4 has length */
/* R5 has pattern */
        cmpi    0,len,0         /* Exit if len <= 0 */
        ble     99f
        andi.   r0,bufp,3       /* Must be on longword boundary */
        bne     10f             /* Use byte loop if not aligned */
        andi.   r0,len,3        /* Check for overrage */
        subi    bufp,bufp,4     /* Adjust pointer */
        srawi   len,len,2       /* Divide by 4 */
        blt     99f             /* If negative - bug out! */
        mtspr   CTR,len         /* Set up counter */
        li      pat,0
00:     stwu    pat,4(bufp)     /* Store value */
        bdnz    00b             /* Loop [based on counter] */
        mr      len,r0          /* Get remainder (bytes) */
10:     cmpi    0,len,0         /* Any bytes left */
        ble     99f             /* No - all done */
        mtspr   CTR,len         /* Set up counter */
        subi    bufp,bufp,1     /* Adjust pointer */
        li      pat,0
20:     stbu    pat,1(bufp)     /* Store value */
        bdnz    20b             /* Loop [based on counter] */
99:     blr

_GLOBAL(abs)
        cmpi    0,r3,0
        bge     10f
        neg     r3,r3
10:     blr

_GLOBAL(_get_SP)
        mr      r3,r1           /* Close enough */
        blr

_GLOBAL(_get_SDR1)
        mfspr   r3,SDR1
        blr

_GLOBAL(_get_SRx)
        mfsrin  r3,r3
        blr

_GLOBAL(_get_PVR)
        mfspr   r3,PVR
        blr

/*
 * Create a kernel thread
 *   __kernel_thread(flags, fn, arg)
 */
#if 0
#define SYS_CLONE       120
_GLOBAL(__kernel_thread)
__kernel_thread:
        li      r0,SYS_CLONE
        sc
        cmpi    0,r3,0
        bnelr
        mtlr    r4
        mr      r3,r5
        blr
#endif
/* Why isn't this a) automatic, b) written in 'C'? */   
        .data
        .align 4
        .globl  sys_call_table
sys_call_table:
        .long sys_setup         /* 0 */
        .long sys_exit
        .long sys_fork
        .long sys_read
        .long sys_write
        .long sys_open                  /* 5 */
        .long sys_close
        .long sys_waitpid
        .long sys_creat
        .long sys_link
        .long sys_unlink                /* 10 */
        .long sys_execve
        .long sys_chdir
        .long sys_time
        .long sys_mknod
        .long sys_chmod         /* 15 */
        .long sys_chown
        .long sys_break
        .long sys_stat
        .long sys_lseek
        .long sys_getpid                /* 20 */
        .long sys_mount
        .long sys_umount
        .long sys_setuid
        .long sys_getuid
        .long sys_stime         /* 25 */
        .long sys_ptrace
        .long sys_alarm
        .long sys_fstat
        .long sys_pause
        .long sys_utime         /* 30 */
        .long sys_stty
        .long sys_gtty
        .long sys_access
        .long sys_nice
        .long sys_ftime         /* 35 */
        .long sys_sync
        .long sys_kill
        .long sys_rename
        .long sys_mkdir
        .long sys_rmdir         /* 40 */
        .long sys_dup
        .long sys_pipe
        .long sys_times
        .long sys_prof
        .long sys_brk                   /* 45 */
        .long sys_setgid
        .long sys_getgid
        .long sys_signal
        .long sys_geteuid
        .long sys_getegid               /* 50 */
        .long sys_acct
        .long sys_phys
        .long sys_lock
        .long sys_ioctl
        .long sys_fcntl         /* 55 */
        .long sys_mpx
        .long sys_setpgid
        .long sys_ulimit
        .long sys_olduname
        .long sys_umask         /* 60 */
        .long sys_chroot
        .long sys_ustat
        .long sys_dup2
        .long sys_getppid
        .long sys_getpgrp               /* 65 */
        .long sys_setsid
        .long sys_sigaction
        .long sys_sgetmask
        .long sys_ssetmask
        .long sys_setreuid              /* 70 */
        .long sys_setregid
        .long sys_sigsuspend
        .long sys_sigpending
        .long sys_sethostname
        .long sys_setrlimit             /* 75 */
        .long sys_getrlimit
        .long sys_getrusage
        .long sys_gettimeofday
        .long sys_settimeofday
        .long sys_getgroups             /* 80 */
        .long sys_setgroups
        .long sys_select
        .long sys_symlink
        .long sys_lstat
        .long sys_readlink              /* 85 */
        .long sys_uselib
        .long sys_swapon
        .long sys_reboot
        .long old_readdir               /* was sys_readdir */
        .long sys_mmap                  /* 90 */
        .long sys_munmap
        .long sys_truncate
        .long sys_ftruncate
        .long sys_fchmod
        .long sys_fchown                /* 95 */
        .long sys_getpriority
        .long sys_setpriority
        .long sys_profil
        .long sys_statfs
        .long sys_fstatfs               /* 100 */
        .long sys_ioperm
        .long sys_socketcall
        .long sys_syslog
        .long sys_setitimer
        .long sys_getitimer             /* 105 */
        .long sys_newstat
        .long sys_newlstat
        .long sys_newfstat
        .long sys_uname
        .long sys_iopl                  /* 110 */
        .long sys_vhangup
        .long sys_idle
        .long sys_vm86
        .long sys_wait4
        .long sys_swapoff               /* 115 */
        .long sys_sysinfo
        .long sys_ipc
        .long sys_fsync
        .long sys_sigreturn
        .long sys_clone         /* 120 */
        .long sys_setdomainname
        .long sys_newuname
        .long sys_modify_ldt
        .long sys_adjtimex
        .long sys_mprotect              /* 125 */
        .long sys_sigprocmask
        .long sys_create_module
        .long sys_init_module
        .long sys_delete_module
        .long sys_get_kernel_syms       /* 130 */
        .long sys_quotactl
        .long sys_getpgid
        .long sys_fchdir
        .long sys_bdflush
        .long sys_sysfs         /* 135 */
        .long sys_personality
        .long 0                         /* for afs_syscall */
        .long sys_setfsuid
        .long sys_setfsgid
        .long sys_llseek                /* 140 */
        .long sys_getdents
        .long sys_newselect
        .long sys_flock
        .long sys_msync
        .long sys_readv         /* 145 */
        .long sys_writev
        .long sys_getsid
        .long sys_fdatasync
        .long sys_sysctl
        .long sys_mlock         /* 150 */
        .long sys_munlock
        .long sys_mlockall
        .long sys_munlockall
        .long sys_sched_setparam
        .long sys_sched_getparam   /* 155 */
        .long sys_sched_setscheduler
        .long sys_sched_getscheduler
        .long sys_sched_yield
        .long sys_sched_get_priority_max
        .long sys_sched_get_priority_min  /* 160 */
        .long sys_sched_rr_get_interval
        .long sys_nanosleep
        .long sys_mremap
        .space (NR_syscalls-163)*4