| 0,0 → 1,58 |
|---|
| #include"ipc.h" |
| #include<stdlib.h> |
| #include<string.h> |
| |
| inline int ipc_messages_avail(ipc_hdr_t * hdr) |
| { |
| return hdr->free_ptr!=8; |
| } |
| |
| static inline void lock_msg_queue(ipc_hdr_t * hdr) |
| { |
| int d0; |
| __asm__ __volatile__( |
| "2:\t" |
| "movb $1,%%al\n\t" |
| "xchgb %%al,%0\n\t" |
| "andb %%al,%%al\n\t" |
| "jnz 2b\n\t" |
| "incb %0" |
| :"=m"(hdr->lock),"=a"(d0) |
| :"m"(hdr->lock) |
| :"memory"); |
| } |
| |
| static inline void unlock_msg_queue(ipc_hdr_t * hdr) |
| { |
| __asm__ __volatile__( |
| "movl $0,%0" |
| :"=m"(hdr->lock) |
| :"m"(hdr->lock) |
| :"memory"); |
| } |
| |
| ipc_msg_t * ipc_receive_msg(ipc_hdr_t * hdr) |
| { |
| ipc_msg_t * msg, * tmp; |
| lock_msg_queue(hdr); |
| if(!ipc_messages_avail(hdr)) |
| { |
| unlock_msg_queue(hdr); |
| return NULL; |
| } |
| tmp=(ipc_msg_t *)hdr->__mem; |
| msg=(ipc_msg_t *)malloc(tmp->msg_length); |
| if(!msg) |
| { |
| unlock_msg_queue(hdr); |
| return NULL; |
| } |
| memcpy(msg,tmp,tmp->msg_length); |
| if(hdr->free_ptr>(8+tmp->msg_length)) |
| { |
| memcpy(tmp,tmp+1,hdr->free_ptr-8-tmp->msg_length); |
| hdr->free_ptr-=tmp->msg_length; |
| } |
| unlock_msg_queue(hdr); |
| return msg; |
| } |