com32/lib/sys/farcall.c

   1 /*
   2  * farcall.c
   3  */
   4
   5 #include <com32.h>
   6
   7 static inline uint32_t eflags(void)
   8 {
   9     //uint32_t v;
  10
  11 #if __SIZEOF_POINTER__ == 4
  12     uint32_t v;
  13     asm volatile("pushfl ; popl %0" : "=rm" (v));
  14 #elif __SIZEOF_POINTER__ == 8
  15     uint64_t v;
  16     asm volatile("pushfq ; pop %0" : "=rm" (v));
  17 #else
  18 #error "Unable to build for to-be-defined architecture type"
  19 #endif
  20     return v;
  21 }
  22
  23 void __farcall(uint16_t cs, uint16_t ip,
  24                const com32sys_t * ireg, com32sys_t * oreg)
  25 {
  26     com32sys_t xreg = *ireg;
  27
  28     /* Enable interrupts if and only if they are enabled in the caller */
  29     xreg.eflags.l = (xreg.eflags.l & ~EFLAGS_IF) | (eflags() & EFLAGS_IF);
  30
  31     __com32.cs_farcall((cs << 16) + ip, &xreg, oreg);
  32 }