diff options
Diffstat (limited to 'sysdeps/unix/sysv/sysv4/linux/i386/sysdep.h')
| -rw-r--r-- | sysdeps/unix/sysv/sysv4/linux/i386/sysdep.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/sysv4/linux/i386/sysdep.h b/sysdeps/unix/sysv/sysv4/linux/i386/sysdep.h new file mode 100644 index 0000000000..d0c1c10dba --- /dev/null +++ b/sysdeps/unix/sysv/sysv4/linux/i386/sysdep.h @@ -0,0 +1,86 @@ +/* Copyright (C) 1992, 1993, 1995 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +/* In the Linux/ELF world, C symbols are asm symbols. */ +#define NO_UNDERSCORES + +/* There is some commonality. */ +#include <sysdeps/unix/i386/sysdep.h> + +#ifdef ASSEMBLER + +/* Linux uses a negative return value to indicate syscall errors, unlike + most Unices, which use the condition codes' carry flag. */ +#undef PSEUDO +#define PSEUDO(name, syscall_name, args) \ + .text; \ + .globl __syscall_error; \ + ENTRY (name) \ + movl $SYS_##syscall_name, %eax; \ + DO_CALL (args) \ + testl %eax, %eax; \ + jl JUMPTARGET(__syscall_error) + + +/* Linux takes system call arguments in registers: + + syscall number %eax call-clobbered + arg 1 %ebx call-saved + arg 2 %ecx call-clobbered + arg 3 %edx call-clobbered + arg 4 %esi call-saved + arg 5 %edi call-saved + + The stack layout upon entering the function is: + + 24(%esp) Arg# 5 + 20(%esp) Arg# 4 + 16(%esp) Arg# 3 + 12(%esp) Arg# 2 + 8(%esp) Arg# 1 + 4(%esp) Return address + (%esp) + + (Of course a function with e.g. 3 argumentS does not have entries for + arguments 4 and 5.) + + We put the arguments into registers from the stack, and save the + call-saved registers, by using the 386 `xchg' instruction to swap the + values in both directions. */ + +#undef DO_CALL +#define DO_CALL(args) \ + DOARGS_##args \ + int $0x80; \ + UNDOARGS_##args \ + +#define DOARGS_0 /* No arguments to frob. */ +#define UNDOARGS_0 /* No arguments to unfrob. */ +#define DOARGS_1 xchg 8(%esp), %ebx; DOARGS_0 /* Save %ebx on stack. */ +#define UNDOARGS_1 xchg 8(%esp), %ebx; UNDOARGS_0 /* Restore %ebx */ +#define DOARGS_2 movel 12(%esp), %ecx; DOARGS_1 +#define UNDOARGS_2 UNDOARGS_1 /* %ecx is clobbered. */ +#define DOARGS_3 movel 16(%esp), %edx; DOARGS_2 +#define UNDOARGS_3 UNDOARGS_2 /* %edx is clobbered. */ +#define DOARGS_4 xchg 20(%esp), %esi; DOARGS_3 /* Save %esi on stack. */ +#define UNDOARGS_4 xchg 20(%esp), %esi; UNDOARGS_3 /* Restore %esi. */ +#define DOARGS_5 xchg 24(%esp), %edi; DOARGS_3 /* Save %edi on stack. */ +#define UNDOARGS_5 xchg 24(%esp), %edi; UNDOARGS_3 /* Restore %edi. */ + + +#endif /* ASSEMBLER */ |