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#ifndef _BITS_SYSCALLS_H
#define _BITS_SYSCALLS_H
#ifndef _SYSCALL_H
# error "Never use <bits/syscalls.h> directly; include <sys/syscall.h> instead."
#endif
/*
* Some of the sneaky macros in the code were taken from
* glibc-2.2.5/sysdeps/unix/sysv/linux/i386/sysdep.h
*/
#ifndef __ASSEMBLER__
#include <errno.h>
#define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
(__extension__ \
({ \
register unsigned int resultvar; \
__asm__ __volatile__ ( \
LOADARGS_##nr \
"movl %1, %%eax\n\t" \
"int $0x80\n\t" \
RESTOREARGS_##nr \
: "=a" (resultvar) \
: "g" (name) ASMFMT_##nr(args) : "memory", "cc" \
); \
(int) resultvar; \
}) \
)
#if 1 /* defined __PIC__ || defined __pic__ */
/* This code avoids pushing/popping ebx as much as possible.
* I think the main reason was that older GCCs had problems
* with proper saving/restoring of ebx if "b" constraint was used,
* which was breaking -fPIC code really badly.
* At least gcc 4.2.x seems to not need these tricks anymore,
* but this code is still useful because it often avoids
* using stack for saving ebx.
* Keeping it unconditionally enabled for now.
*/
/* We need some help from the assembler to generate optimal code.
* We define some macros here which later will be used. */
/* FIXME: drop these b* macros! */
__asm__ (
".L__X'%ebx = 1\n\t"
".L__X'%ecx = 2\n\t"
".L__X'%edx = 2\n\t"
".L__X'%eax = 3\n\t"
".L__X'%esi = 3\n\t"
".L__X'%edi = 3\n\t"
".L__X'%ebp = 3\n\t"
".L__X'%esp = 3\n\t"
/* Loading param #1 (ebx) is done by loading it into
* another register, and then performing bpushl+bmovl,
* since we must preserve ebx */
".macro bpushl name reg\n\t"
".if 1 - \\name\n\t" /* if reg!=ebx... */
".if 2 - \\name\n\t" /* if reg can't be clobbered... */
"pushl %ebx\n\t" /* save ebx on stack */
".else\n\t"
"xchgl \\reg, %ebx\n\t" /* else save ebx in reg, and load reg to ebx */
".endif\n\t"
".endif\n\t"
".endm\n\t"
".macro bmovl name reg\n\t"
".if 1 - \\name\n\t"
".if 2 - \\name\n\t" /* if reg can't be clobbered... */
"movl \\reg, %ebx\n\t" /* load reg to ebx */
".endif\n\t"
".endif\n\t"
".endm\n\t"
".macro bpopl name reg\n\t"
".if 1 - \\name\n\t"
".if 2 - \\name\n\t" /* if reg can't be clobbered... */
"popl %ebx\n\t" /* restore ebx from stack */
".else\n\t"
"xchgl \\reg, %ebx\n\t" /* else restore ebx from reg */
".endif\n\t"
".endif\n\t"
".endm\n\t"
);
#define LOADARGS_0
#define LOADARGS_1 "bpushl .L__X'%k2, %k2\n\t" "bmovl .L__X'%k2, %k2\n\t"
#define LOADARGS_2 LOADARGS_1
#define LOADARGS_3 LOADARGS_1
#define LOADARGS_4 LOADARGS_1
#define LOADARGS_5 LOADARGS_1
#define LOADARGS_6 LOADARGS_1 "push %%ebp\n\t" "movl %7, %%ebp\n\t"
#define RESTOREARGS_0
#define RESTOREARGS_1 "bpopl .L__X'%k2, %k2\n\t"
#define RESTOREARGS_2 RESTOREARGS_1
#define RESTOREARGS_3 RESTOREARGS_1
#define RESTOREARGS_4 RESTOREARGS_1
#define RESTOREARGS_5 RESTOREARGS_1
#define RESTOREARGS_6 "pop %%ebp\n\t" RESTOREARGS_1
#define ASMFMT_0()
/* "acdSD" constraint would work too, but "SD" would use esi/edi and cause
* them to be pushed/popped by compiler, "a" would use eax and cause ebx
* to be saved/restored on stack, not in register. Narrowing choice down
* to "ecx or edx" results in smaller and faster code: */
#define ASMFMT_1(arg1) \
, "cd" (arg1)
/* Can use "adSD" constraint here: */
#define ASMFMT_2(arg1, arg2) \
, "d" (arg1), "c" (arg2)
/* Can use "aSD" constraint here: */
#define ASMFMT_3(arg1, arg2, arg3) \
, "a" (arg1), "c" (arg2), "d" (arg3)
/* Can use "aD" constraint here: */
#define ASMFMT_4(arg1, arg2, arg3, arg4) \
, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4)
#define ASMFMT_5(arg1, arg2, arg3, arg4, arg5) \
, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
#define ASMFMT_6(arg1, arg2, arg3, arg4, arg5, arg6) \
, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5), "g" (arg6)
#else /* !PIC */
/* Simpler code which just uses "b" constraint to load ebx.
* Seems to work with gc 4.2.x, and generates slightly smaller,
* but slightly slower code. Example (time syscall):
*
* - 8b 4c 24 04 mov 0x4(%esp),%ecx
* - 87 cb xchg %ecx,%ebx
* + 53 push %ebx
* + 8b 5c 24 08 mov 0x8(%esp),%ebx
* b8 0d 00 00 00 mov $0xd,%eax
* cd 80 int $0x80
* - 87 cb xchg %ecx,%ebx
* + 5b pop %ebx
* c3 ret
*
* 2 bytes smaller, but uses stack via "push/pop ebx"
*/
#define LOADARGS_0
#define LOADARGS_1
#define LOADARGS_2
#define LOADARGS_3
#define LOADARGS_4
#define LOADARGS_5
#define LOADARGS_6 "push %%ebp\n\t" "movl %7, %%ebp\n\t"
#define RESTOREARGS_0
#define RESTOREARGS_1
#define RESTOREARGS_2
#define RESTOREARGS_3
#define RESTOREARGS_4
#define RESTOREARGS_5
#define RESTOREARGS_6 "pop %%ebp\n\t"
#define ASMFMT_0()
#define ASMFMT_1(arg1) \
, "b" (arg1)
#define ASMFMT_2(arg1, arg2) \
, "b" (arg1), "c" (arg2)
#define ASMFMT_3(arg1, arg2, arg3) \
, "b" (arg1), "c" (arg2), "d" (arg3)
#define ASMFMT_4(arg1, arg2, arg3, arg4) \
, "b" (arg1), "c" (arg2), "d" (arg3), "S" (arg4)
#define ASMFMT_5(arg1, arg2, arg3, arg4, arg5) \
, "b" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
#define ASMFMT_6(arg1, arg2, arg3, arg4, arg5, arg6) \
, "b" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5), "m" (arg6)
#endif /* !PIC */
#endif /* __ASSEMBLER__ */
#endif /* _BITS_SYSCALLS_H */
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