c_run_irqs.diff

   1 diff -uNrX dosemu-ignore-files dosemu-1.1.1.3.eb1.1/src/base/dev/pic/pic.c
   2 dosemu-1.1.1.3.eb1.1.1/src/base/dev/pic/pic.c
   3 --- src/base/dev/pic/pic.c Sat Oct 27 16:58:43 2001
   4 +++ src/base/dev/pic/pic.c       Sun Oct 28 08:57:08 2001
   5 @@ -134,7 +134,6 @@
   6  #ifndef C_RUN_IRQS
   7  #define C_RUN_IRQS
   8  #include "bitops.h"
   9 -#undef C_RUN_IRQS
  10  #else
  11  #include "bitops.h"
  12  #endif
  13 @@ -632,55 +631,83 @@
  14   * assembly macros, because such macros can only return a single result.
  15   * If I find a way to do it in c, I will, but don't hold your breath.
  16   *
  17 + * I found a way to write it in C --EB 15 Jan 97
  18 + *
  19   * DANG_END_FUNCTION
  20   */
  21  #ifdef C_RUN_IRQS
  22 +/* DANG_BEGIN_COMMENT
  23 + *   This is my C version of the assembly version of run_irqs.
  24 + *   I believe it is a correct translation of the assembly into C.
  25 + *
  26 + *   I got frustrated with the old incomplete version.  Especially
  27 + *   because of indent problems and I don't believe in changing code I
  28 + *   don't understand.
  29 + *
  30 + *   This code is correct in the single process case.
  31 + *   Except possilby it's handling of special mask mode.
  32 + *   If pic_smm is set to 32 it appears to me that no interrupt is
  33 + *   ever run.
  34 + *
  35 + *   But this code is certainly incorrect in the multiple process
  36 + *   case.  Because it spins without rereading pic_irr, to recalculate
  37 + *   pic_ilevel.  And I think there are other less serious problems as
  38 + *   well.  However it doesn't matter because we aren't doing multiple
  39 + *   processes, or multiple threads. :)
  40 + *
  41 + *   Note Comments taken from the original C version
  42 + *
  43 + *   --EB 5 Jan 97
  44 + *  DANG_END_COMMENT
  45 + */
  46  /* see assembly language version below */
  47 -void run_irqs()
  48 +void run_irqs(void)
  49  /* find the highest priority unmasked requested irq and run it */
  50  {
  51 - int old_ilevel;
  52 - int int_request;
  53 +       int old_ilevel;
  54 +       int int_request;
  55 +       int priority;
  56  #warning using C run_irqs
  57 +       /* Old hack, to be removed */
  58 +       if (in_dpmi && in_dpmi_timer_int) return;
  59
  60 -/* check for and find any requested irqs.  Having found one, we atomic-ly
  61 - * clear it and verify it was there when we cleared it.  If it wasn't, we
  62 - * look for the next request.  There are two in_service bits for pic1 irqs.
  63 - * This is needed, because irq 8-15 must do 2 outb20s, which, if the dos
  64 - * irq code actually runs, will reset the bits.  We also reset them here,
  65 - * since dos code won't necessarily run.
  66 - */
  67 -
  68 -#if 0
  69 - if(!(pic_irr&~(pic_isr|pic_imr))) return;     /* exit if nothing to do */
  70 -#else
  71 - if(!(pic_irr&~(pic_isr))) return;     /* exit if nothing to do */
  72 -#endif
  73 - old_ilevel=pic_ilevel;                          /* save old pic_ilevl   */
  74 -
  75 -#if 0
  76 - while(int_request= pic_irr&~(pic_isr|pic_imr)) /* while something to do*/
  77 -#else
  78 - while(int_request= pic_irr&~(pic_isr)) /* while something to do*/
  79 -#endif
  80 -  {
  81 -
  82 -  pic_ilevel=find_bit(&int_request);              /* find out what it is  */
  83 -
  84 -  if(pic_ilevel<(old_ilevel+pic_smm))            /* priority check       */
  85 -    if(clear_bit(pic_ilevel,&pic_irr))           /* dbl check & clear req*/
  86 -      {
  87 -      /* we got one!  it is identified by pic_ilevel */
  88 -
  89 -     set_bit(pic_ilevel,&pic_isr);               /* set in-service bit   */
  90 -     pic1_isr = pic_isr & pic1_mask;            /* pic1 too            */
  91 -     pic_iinfo[pic_ilevel].func();               /* run the function     */
  92 -     clear_bit(pic_ilevel,&pic_isr);             /* clear in_service bit */
  93 -     clear_bit(pic_ilevel,&pic1_isr);            /* pic1 too            */
  94 -     }
  95 -   }
  96 -   /* whether we did or didn't :-( get one, we must still reset pic_ilevel */
  97 -   pic_ilevel=old_ilevel;
  98 +       /* check for and find any requested irqs.  Having found one, we atomic-ly
  99 +        * clear it and verify it was there when we cleared it.  If it wasn't, we
 100 +        * look for the next request.  There are two in_service bits for pic1 irqs.
 101 +        * This is needed, because irq 8-15 must do 2 outb20s, which, if the dos
 102 +        * irq code actually runs, will reset the bits.  We also reset them here,
 103 +        * since dos code won't necessarily run.
 104 +        */
 105 +
 106 +       old_ilevel=pic_ilevel;                          /* save old pic_ilevl   */
 107 +       priority = pic_smm + old_ilevel;                /* check spec. mask mode       */
 108 +
 109 +       while((int_request = pic_irr & ~(pic_isr | pic_imr)) != 0) { /* while something to do*/
 110 +               int local_pic_ilevel;
 111 +
 112 +              if (!isset_IF() && !in_dpmi)
 113 +                      goto exit;                      /* exit if ints are disabled */
 114 +
 115 +               do {
 116 +                       local_pic_ilevel = find_bit(int_request);    /* find out what it is  */
 117 +                       /* In case int_request has no bits set */
 118 +                       if (local_pic_ilevel == -1)
 119 +                               goto exit;
 120 +                       if (local_pic_ilevel > priority)  /* priority check */
 121 +                               goto exit;
 122 +               } while (clear_bit(local_pic_ilevel, &pic_irr) == 0);   /* dbl check & clear req */
 123 +               pic_ilevel = local_pic_ilevel;
 124 +               set_bit(local_pic_ilevel, &pic_isr);     /* set in-service bit */
 125 +               set_bit(local_pic_ilevel, &pic1_isr);    /* pic1 too */
 126 +               pic1_isr &= pic_isr & pic1_mask;         /* isolate pic1 irqs */
 127 +               pic_iinfo[local_pic_ilevel].func();      /* run the function */
 128 +               local_pic_ilevel = pic_ilevel;
 129 +               clear_bit(local_pic_ilevel, &pic_isr);   /* clear in_service bit */
 130 +               clear_bit(local_pic_ilevel, &pic1_isr);  /* pic1 too */
 131 +       }
 132 + exit:
 133 +       /* whether we did or didn't :-( get one, we must still reset pic_ilevel */
 134 +       pic_ilevel=old_ilevel;
 135  }
 136
 137  #else
 138 --- src/include/bitops.h   Sun Mar  5 05:57:39 2000
 139 +++ src/include/bitops.h Sun Oct 28 08:58:04 2001
 140 @@ -35,7 +35,7 @@
 141  #define _STATIC_ static
 142  #endif
 143
 144 -_STATIC_ int find_bit(void * addr);
 145 +_STATIC_ int find_bit(unsigned long int word);
 146  _STATIC_ long atomic_inc(long * addr);
 147  _STATIC_ long atomic_dec(long * addr);
 148  _STATIC_ int set_bit(int nr, void * addr);
 149 @@ -60,18 +60,20 @@
 150  #define ADDR (*(struct __dummy *) addr)
 151
 152  /* JLS's stuff */
 153 -/* find_bit returns the bit number of the lowest bit that's set */
 154 -/* it doesn't need to be atomic, but it's much faster than using c */
 155 -
 156 +/*
 157 + * find_bit returns the bit number of the lowest bit that's set
 158 + * Returns -1 if no one exists.
 159 + */
 160  _INLINE_ int
 161 -find_bit(void *addr)
 162 +find_bit(unsigned long int word)
 163  {
 164 -    int             bitno;
 165 -
 166 -    __asm__         __volatile__("bsfl %1,%0"
 167 -                                :"=r"           (bitno):"m"(ADDR));
 168 -    return bitno;
 169 +       int result = -1; /* value to return on error */
 170 +       __asm__("bsfl %2,%0"
 171 +               :"=r" (result) /* output */
 172 +               :"0" (result), "r" (word)); /* input */
 173 +       return result;
 174  }
 175 +
 176  /* atomic increment flag and decrement flag operations */
 177  _INLINE_ long int
 178  atomic_inc(long *addr)