include/asm-m68k/system.h

   1 #ifndef _M68K_SYSTEM_H
   2 #define _M68K_SYSTEM_H
   3
   4 #include <linux/config.h> /* get configuration macros */
   5 #include <linux/linkage.h>
   6 #include <asm/segment.h>
   7
   8 extern inline unsigned long rdusp(void) {
   9         unsigned long usp;
  10
  11         __asm__ __volatile__("move %/usp,%0" : "=a" (usp));
  12         return usp;
  13 }
  14
  15 extern inline void wrusp(unsigned long usp) {
  16         __asm__ __volatile__("move %0,%/usp" : : "a" (usp));
  17 }
  18
  19 /*
  20  * switch_to(n) should switch tasks to task ptr, first checking that
  21  * ptr isn't the current task, in which case it does nothing.  This
  22  * also clears the TS-flag if the task we switched to has used the
  23  * math co-processor latest.
  24  */
  25 /*
  26  * switch_to() saves the extra registers, that are not saved
  27  * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and
  28  * a0-a1. Some of these are used by schedule() and its predecessors
  29  * and so we might get see unexpected behaviors when a task returns
  30  * with unexpected register values.
  31  *
  32  * syscall stores these registers itself and none of them are used
  33  * by syscall after the function in the syscall has been called.
  34  *
  35  * Beware that resume now expects *next to be in d1 and the offset of
  36  * tss to be in a1. This saves a few instructions as we no longer have
  37  * to push them onto the stack and read them back right after.
  38  *
  39  * 02/17/96 - Jes Sorensen (jds@kom.auc.dk)
  40  *
  41  * Changed 96/09/19 by Andreas Schwab
  42  * pass prev in a0, next in a1, offset of tss in d1, and whether
  43  * the mm structures are shared in d2 (to avoid atc flushing).
  44  */
  45 asmlinkage void resume(void);
  46 #define switch_to(prev,next) { \
  47   register void *_prev __asm__ ("a0") = (prev); \
  48   register void *_next __asm__ ("a1") = (next); \
  49   __asm__ __volatile__("jbsr " SYMBOL_NAME_STR(resume) \
  50                        : : "a" (_prev), "a" (_next) \
  51                        : "d0", "d1", "d2", "d3", "d4", "d5", "a0", "a1"); \
  52 }
  53
  54 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  55 #define tas(ptr) (xchg((ptr),1))
  56
  57 struct __xchg_dummy { unsigned long a[100]; };
  58 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
  59
  60 #if defined(MACH_ATARI_ONLY) && !defined(CONFIG_HADES)
  61 /* block out HSYNC on the atari */
  62 #define __sti() __asm__ __volatile__ ("andiw #0xfbff,%/sr": : : "memory")
  63 #else /* portable version */
  64 #define __sti() __asm__ __volatile__ ("andiw #0xf8ff,%/sr": : : "memory")
  65 #endif /* machine compilation types */
  66 #define __cli() __asm__ __volatile__ ("oriw  #0x0700,%/sr": : : "memory")
  67 #define nop() __asm__ __volatile__ ("nop"::)
  68 #define mb()  __asm__ __volatile__ (""   : : :"memory")
  69
  70 #define __save_flags(x) \
  71 __asm__ __volatile__("movew %/sr,%0":"=d" (x) : /* no input */ :"memory")
  72
  73 #define __restore_flags(x) \
  74 __asm__ __volatile__("movew %0,%/sr": /* no outputs */ :"d" (x) : "memory")
  75
  76 #define cli() __cli()
  77 #define sti() __sti()
  78 #define save_flags(x) __save_flags(x)
  79 #define restore_flags(x) __restore_flags(x)
  80 #define save_and_cli(flags)   do { save_flags(flags); cli(); } while(0)
  81
  82 #ifndef CONFIG_RMW_INSNS
  83 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
  84 {
  85   unsigned long tmp, flags;
  86
  87   save_flags(flags);
  88   cli();
  89
  90   switch (size) {
  91   case 1:
  92     __asm__ __volatile__
  93     ("moveb %2,%0\n\t"
  94      "moveb %1,%2"
  95     : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
  96     break;
  97   case 2:
  98     __asm__ __volatile__
  99     ("movew %2,%0\n\t"
 100      "movew %1,%2"
 101     : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 102     break;
 103   case 4:
 104     __asm__ __volatile__
 105     ("movel %2,%0\n\t"
 106      "movel %1,%2"
 107     : "=&d" (tmp) : "d" (x), "m" (*__xg(ptr)) : "memory");
 108     break;
 109   }
 110   restore_flags(flags);
 111   return tmp;
 112 }
 113 #else
 114 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 115 {
 116         switch (size) {
 117             case 1:
 118                 __asm__ __volatile__
 119                         ("moveb %2,%0\n\t"
 120                          "1:\n\t"
 121                          "casb %0,%1,%2\n\t"
 122                          "jne 1b"
 123                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
 124                 break;
 125             case 2:
 126                 __asm__ __volatile__
 127                         ("movew %2,%0\n\t"
 128                          "1:\n\t"
 129                          "casw %0,%1,%2\n\t"
 130                          "jne 1b"
 131                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
 132                 break;
 133             case 4:
 134                 __asm__ __volatile__
 135                         ("movel %2,%0\n\t"
 136                          "1:\n\t"
 137                          "casl %0,%1,%2\n\t"
 138                          "jne 1b"
 139                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
 140                 break;
 141         }
 142         return x;
 143 }
 144 #endif
 145
 146 #endif /* _M68K_SYSTEM_H */