forked from KolibriOS/kolibrios
6496d04506
This version of menuetlibc was taken from revision 4743, right before I made any changes git-svn-id: svn://kolibrios.org@4973 a494cfbc-eb01-0410-851d-a64ba20cac60
59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
#include"ipc.h"
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#include<stdlib.h>
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#include<string.h>
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inline int ipc_messages_avail(ipc_hdr_t * hdr)
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{
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return hdr->free_ptr!=8;
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}
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static inline void lock_msg_queue(ipc_hdr_t * hdr)
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{
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int d0;
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__asm__ __volatile__(
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"2:\t"
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"movb $1,%%al\n\t"
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"xchgb %%al,%0\n\t"
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"andb %%al,%%al\n\t"
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"jnz 2b\n\t"
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"incb %0"
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:"=m"(hdr->lock),"=a"(d0)
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:"m"(hdr->lock)
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:"memory");
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}
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static inline void unlock_msg_queue(ipc_hdr_t * hdr)
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{
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__asm__ __volatile__(
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"movl $0,%0"
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:"=m"(hdr->lock)
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:"m"(hdr->lock)
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:"memory");
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}
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ipc_msg_t * ipc_receive_msg(ipc_hdr_t * hdr)
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{
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ipc_msg_t * msg, * tmp;
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lock_msg_queue(hdr);
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if(!ipc_messages_avail(hdr))
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{
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unlock_msg_queue(hdr);
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return NULL;
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}
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tmp=(ipc_msg_t *)hdr->__mem;
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msg=(ipc_msg_t *)malloc(tmp->msg_length);
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if(!msg)
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{
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unlock_msg_queue(hdr);
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return NULL;
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}
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memcpy(msg,tmp,tmp->msg_length);
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if(hdr->free_ptr>(8+tmp->msg_length))
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{
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memcpy(tmp,tmp+1,hdr->free_ptr-8-tmp->msg_length);
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hdr->free_ptr-=tmp->msg_length;
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}
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unlock_msg_queue(hdr);
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return msg;
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}
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