source: trunk/minix/lib/i386/rts/_ipcnew.s@ 18

.sect .text; .sect .rom; .sect .data; .sect .bss
.define __ipc_request, __ipc_reply, __ipc_notify, __ipc_receive

! See src/kernel/ipc.h for C definitions.
IPC_REQUEST = 16                ! each gets a distinct bit
IPC_REPLY = 32
IPC_NOTIFY = 64
IPC_RECEIVE = 128

SYSVEC = 33                     ! trap to kernel 

! Offsets of arguments relative to stack pointer.
SRC_DST = 8                     ! source/ destination process 
SEND_MSG = 12                   ! message pointer for sending 
EVENT_SET = 12                  ! notification event set 
RECV_MSG = 16                   ! message pointer for receiving 


!*========================================================================*
!                           IPC assembly routines                         *
!*========================================================================*
! all message passing routines save ebp, but destroy eax, ecx, and edx.
.define __ipc_request, __ipc_reply, __ipc_notify, __ipc_receive
.sect .text

__ipc_request:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! eax = destination
        mov     ebx, SEND_MSG(ebp)      ! ebx = message pointer
        mov     ecx, IPC_REQUEST        ! _ipc_request(dst, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__ipc_reply:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! eax = destination
        mov     ebx, SEND_MSG(ebp)      ! ebx = message pointer
        mov     ecx, IPC_REPLY          ! _ipc_reply(dst, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__ipc_receive:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! eax = source
        mov     edx, EVENT_SET(ebp)     ! ebx = event set
        mov     ebx, RCV_MSG(ebp)       ! ebx = message pointer
        mov     ecx, IPC_RECEIVE        ! _ipc_receive(src, events, ptr)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret

__ipc_notify:
        push    ebp
        mov     ebp, esp
        push    ebx
        mov     eax, SRC_DST(ebp)       ! ebx = destination 
        mov     edx, EVENT_SET(ebp)     ! edx = event set 
        mov     ecx, IPC_NOTIFY         ! _ipc_notify(dst, events)
        int     SYSVEC                  ! trap to the kernel
        pop     ebx
        pop     ebp
        ret