Update of /cvsroot/linux-vax/kernel-2.4/include/asm-vax
In directory usw-pr-cvs1:/tmp/cvs-serv22488/include/asm-vax
Modified Files:
unistd.h
Log Message:
DA: added some comments
Index: unistd.h
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/include/asm-vax/unistd.h,v
retrieving revision 1.5
retrieving revision 1.6
diff -u -r1.5 -r1.6
--- unistd.h 2001/05/20 19:34:09 1.5
+++ unistd.h 2001/05/23 22:26:00 1.6
@@ -1,6 +1,12 @@
#ifndef _ASM_VAX_UNISTD_H_
#define _ASM_VAX_UNISTD_H_
+/*
+ * syscall macros Copyright (c) David Airlie 2001 (ai...@li...)
+ * -- see comments
+ */
+
+
/* FIXME: Who do we want to be compatible with?
* e.g. see ../asm-mips/unistd.h
*/
@@ -200,6 +206,22 @@
/* user-visible error numbers are in the range -1 - -122: see <asm-i386/errno.h> */
+/*
+ * syscall functions for system calls with 0->5 arguments are implemented
+ * here-in, for inclusion in libc also.
+ * All syscalls are implemented the same, the syscall arguments are
+ * pushed onto the stack, the number of arguments is pushed, the sp
+ * is loaded into the ap register and the chmk call is made with the
+ * syscall number as the argument in the r0 register.
+ *
+ * Possible optimisations, don't need to use r0 to pass the chmk argument
+ * suggested by Kenn, will examine later as we are using r0 for the
+ * return value.
+ *
+ * Opposing code is in arch/vax/kernel/syscall.c as is from Kenn Humborg,
+ * any changes here should be reflected there and vice-versa.
+ * - Dave Airlie, May 2001
+ */
/* this from alpha port, easier to rework - atp */
#define _syscall_return(type) \
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