usr/src/lib/libc/tahoe/sys/syscall.s

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#if defined(SYSLIBC_SCCS) && !defined(lint)
        .asciz "@(#)syscall.s   5.4 (Berkeley) %G%"
#endif /* SYSLIBC_SCCS and not lint */

#include "SYS.h"

ENTRY(syscall)
        pushl   4(fp)           # syscall number
        movl    fp,r0           # point to the arg list
        movl    -4(fp),r1       # (arg_count + 1) (bytes) | mask
        andl2   $0xFFFF,r1      # clear the mask bits
        shrl    $2,r1,r1        # convert to words
        subl2   $2,r1           # don't count the first arg
1:
        addl2   $4,r0           # point to the next arg
        movl    4(r0),(r0)      # move an arg down
        decl    r1              # count it
        jgtr    1b              # any more?
        movl    (sp)+,r0        # no, get the syscall number back
        kcall   r0
        jcs     1f
        ret
1:
        jmp     cerror