jpg.c

#ifdef __GNUC__
#include <stdint.h>

static int32_t wordval;
static int32_t start_neg_pow2 ;

uint16_t lookKbits(uint8_t k)
{
  __asm__("movb %0,%%dl" : : "g"(k) );
  __asm__("movb 6,%cl");
  __asm__("subb %dl,%cl");
  __asm__("movl wordval, %eax" );
  __asm__("shrl %cl,%eax");
}


uint16_t WORD_hi_lo(uint8_t byte_high,uint8_t byte_low)
{
  __asm__("movb %0,%%ah" : : "g"(byte_high));
  __asm__("movb %0,%%al" : : "g"(byte_low));
}
int16_t get_svalue(uint8_t k)
// k>0 always
// Takes k bits out of the BIT stream (wordval), and makes them a signed value
{
  __asm__("xorl %ecx,%ecx");
  __asm__("movb %0,%%cl" : : "g"(k) );
  __asm__("movl wordval,%eax");
  __asm__("shll %cl,%eax");
  __asm__("shrl $16,%eax");
  __asm__("decb %cl");
  __asm__("btl %ecx,%eax");
  __asm__("jc end_macro");
  __asm__("signed_value:incb %cl");
  __asm__("movl start_neg_pow2,%ebx");
  __asm__("addw (%ebx,%ecx,2),%ax");
  __asm__("end_macro:");
}
#endif