LXR syslinux/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 */
  18uint8_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
  28uint16_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
  37uint32_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 */
  47uint64_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 */
  59void 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
  66void 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
  72void 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
  78void 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
  85void 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
 102void 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}
 118