hw/xfree86/os-support/misc/SlowBcopy.c

   1 /*******************************************************************************
   2   for Alpha Linux
   3 *******************************************************************************/
   4
   5 /*
   6  *   Create a dependency that should be immune from the effect of register
   7  *   renaming as is commonly seen in superscalar processors.  This should
   8  *   insert a minimum of 100-ns delays between reads/writes at clock rates
   9  *   up to 100 MHz---GGL
  10  *
  11  *   Slowbcopy(char *src, char *dst, int count)
  12  *
  13  */
  14
  15 #ifdef HAVE_XORG_CONFIG_H
  16 #include <xorg-config.h>
  17 #endif
  18
  19 #include <X11/X.h>
  20 #include "xf86.h"
  21 #include "xf86Priv.h"
  22 #include "xf86_OSlib.h"
  23 #include "compiler.h"
  24
  25 static int really_slow_bcopy;
  26
  27 void
  28 xf86SetReallySlowBcopy(void)
  29 {
  30     really_slow_bcopy = 1;
  31 }
  32
  33 #if defined(__i386__) || defined(__amd64__)
  34 static void
  35 xf86_really_slow_bcopy(unsigned char *src, unsigned char *dst, int len)
  36 {
  37     while (len--) {
  38         *dst++ = *src++;
  39         outb(0x80, 0x00);
  40     }
  41 }
  42 #endif
  43
  44 /* The outb() isn't needed on my machine, but who knows ... -- ost */
  45 void
  46 xf86SlowBcopy(unsigned char *src, unsigned char *dst, int len)
  47 {
  48 #if defined(__i386__) || defined(__amd64__)
  49     if (really_slow_bcopy) {
  50         xf86_really_slow_bcopy(src, dst, len);
  51         return;
  52     }
  53 #endif
  54     while (len--)
  55         *dst++ = *src++;
  56 }
  57
  58 #ifdef __alpha__
  59
  60 #ifdef linux
  61
  62 unsigned long _bus_base(void);
  63
  64 #define useSparse() (!_bus_base())
  65
  66 #define SPARSE (7)
  67
  68 #else
  69
  70 #define useSparse() 0
  71
  72 #define SPARSE 0
  73
  74 #endif
  75
  76 void
  77 xf86SlowBCopyFromBus(unsigned char *src, unsigned char *dst, int count)
  78 {
  79     if (useSparse()) {
  80         unsigned long addr;
  81         long result;
  82
  83         addr = (unsigned long) src;
  84         while (count) {
  85             result = *(volatile int *) addr;
  86             result >>= ((addr >> SPARSE) & 3) * 8;
  87             *dst++ = (unsigned char) (0xffUL & result);
  88             addr += 1 << SPARSE;
  89             count--;
  90             outb(0x80, 0x00);
  91         }
  92     }
  93     else
  94         xf86SlowBcopy(src, dst, count);
  95 }
  96
  97 void
  98 xf86SlowBCopyToBus(unsigned char *src, unsigned char *dst, int count)
  99 {
 100     if (useSparse()) {
 101         unsigned long addr;
 102
 103         addr = (unsigned long) dst;
 104         while (count) {
 105             *(volatile unsigned int *) addr =
 106                 (unsigned short) (*src) * 0x01010101;
 107             src++;
 108             addr += 1 << SPARSE;
 109             count--;
 110             outb(0x80, 0x00);
 111         }
 112     }
 113     else
 114         xf86SlowBcopy(src, dst, count);
 115 }
 116 #endif