dos/getsetsl.c

   1 /*
   2  * Special handling for the MS-DOS derivative: syslinux_ldlinux
   3  * is a "far" object...
   4  */
   5
   6 #define _XOPEN_SOURCE 500       /* Required on glibc 2.x */
   7 #define _BSD_SOURCE
   8 #include <inttypes.h>
   9 #include <string.h>
  10 #include <stddef.h>
  11 #include <stdlib.h>
  12
  13 #include "syslxint.h"
  14
  15 #define __noinline __attribute__((noinline))
  16
  17 #if 0                           /* unused */
  18 uint8_t get_8_sl(const uint8_t * p)
  19 {
  20     uint8_t v;
  21
  22     p = set_fs(p);
  23     asm volatile("movb %%fs:%1,%0":"=q" (v):"m"(*p));
  24     return v;
  25 }
  26 #endif
  27
  28 uint16_t get_16_sl(const uint16_t * p)
  29 {
  30     uint16_t v;
  31
  32     p = set_fs(p);
  33     asm volatile("movw %%fs:%1,%0":"=r" (v):"m"(*p));
  34     return v;
  35 }
  36
  37 uint32_t get_32_sl(const uint32_t * p)
  38 {
  39     uint32_t v;
  40
  41     p = set_fs(p);
  42     asm volatile("movl %%fs:%1,%0":"=r" (v):"m"(*p));
  43     return v;
  44 }
  45
  46 #if 0                           /* unused */
  47 uint64_t get_64_sl(const uint64_t * p)
  48 {
  49     uint32_t v0, v1;
  50     const uint32_t *pp = (const uint32_t *)set_fs(p);
  51
  52     asm volatile("movl %%fs:%1,%0" : "=r" (v0) : "m" (pp[0]));
  53     asm volatile("movl %%fs:%1,%0" : "=r" (v1) : "m" (pp[1]));
  54     return v0 + ((uint64_t)v1 << 32);
  55 }
  56 #endif
  57
  58 #if 0                           /* unused */
  59 void set_8_sl(uint8_t * p, uint8_t v)
  60 {
  61     p = set_fs(p);
  62     asm volatile("movb %1,%%fs:%0":"=m" (*p):"qi"(v));
  63 }
  64 #endif
  65
  66 void set_16_sl(uint16_t * p, uint16_t v)
  67 {
  68     p = set_fs(p);
  69     asm volatile("movw %1,%%fs:%0":"=m" (*p):"ri"(v));
  70 }
  71
  72 void set_32_sl(uint32_t * p, uint32_t v)
  73 {
  74     p = set_fs(p);
  75     asm volatile("movl %1,%%fs:%0":"=m" (*p):"ri"(v));
  76 }
  77
  78 void set_64_sl(uint64_t * p, uint64_t v)
  79 {
  80     uint32_t *pp = (uint32_t *)set_fs(p);
  81     asm volatile("movl %1,%%fs:%0" : "=m" (pp[0]) : "ri"((uint32_t)v));
  82     asm volatile("movl %1,%%fs:%0" : "=m" (pp[1]) : "ri"((uint32_t)(v >> 32)));
  83 }
  84
  85 void memcpy_to_sl(void *dst, const void *src, size_t len)
  86 {
  87     uint16_t seg;
  88     uint16_t off;
  89
  90     seg = ds() + ((size_t)dst >> 4);
  91     off = (size_t)dst & 15;
  92
  93     asm volatile("pushw %%es ; "
  94                  "movw %3,%%es ; "
  95                  "rep ; movsb ; "
  96                  "popw %%es"
  97                  : "+D" (off), "+S" (src), "+c" (len)
  98                  : "r" (seg)
  99                  : "memory");
 100 }
 101
 102 void memcpy_from_sl(void *dst, const void *src, size_t len)
 103 {
 104     uint16_t seg;
 105     uint16_t off;
 106
 107     seg = ds() + ((size_t)src >> 4);
 108     off = (size_t)src & 15;
 109
 110     asm volatile("pushw %%ds ; "
 111                  "movw %3,%%ds ; "
 112                  "rep ; movsb ; "
 113                  "popw %%ds"
 114                  : "+D" (dst), "+S" (off), "+c" (len)
 115                  : "r" (seg)
 116                  : "memory");
 117 }