source: trunk/minix/lib/i386/rts/_ipc.s@ 10

.sect .text; .sect .rom; .sect .data; .sect .bss
.define __echo, __notify, __send, __receive, __sendrec 

! See src/kernel/ipc.h for C definitions
SEND = 1
RECEIVE = 2
SENDREC = 3 
NOTIFY = 4
ECHO = 8
SYSVEC = 33                     ! trap to kernel 

SRC_DST = 8                     ! source/ destination process 
ECHO_MESS = 8                   ! echo doesn't have SRC_DST 
MESSAGE = 12                    ! message pointer 

!*========================================================================*
!                           IPC assembly routines                         *
!*========================================================================*
! all message passing routines save ebp, but destroy eax and ecx.
.define __echo, __notify, __send, __receive, __sendrec 
.sect .text
__send:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! eax = dest-src
        mov     ebx, MESSAGE(ebp)       ! ebx = message pointer
        mov     ecx, SEND               ! _send(dest, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__receive:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! eax = dest-src
        mov     ebx, MESSAGE(ebp)       ! ebx = message pointer
        mov     ecx, RECEIVE            ! _receive(src, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__sendrec:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! eax = dest-src
        mov     ebx, MESSAGE(ebp)       ! ebx = message pointer
        mov     ecx, SENDREC            ! _sendrec(srcdest, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__notify:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! ebx = destination 
        mov     ecx, NOTIFY             ! _notify(srcdst)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__echo:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     ebx, ECHO_MESS(ebp)     ! ebx = message pointer
        mov     ecx, ECHO               ! _echo(srcdest, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret