//
// RMG's syscallX macros for 64-bit systems;
// only syscall0 - syscall3 are supplied; these are based 
// on the register layout in /usr/src/linux/arch/x86/kernel/entry_64.S:
//
/*
 * Register setup:
 * rax  system call number
 * rdi  arg0
 * rcx  return address for syscall/sysret, C arg3
 * rsi  arg1
 * rdx  arg2
 * r10  arg3 	(--> moved to rcx for C)
 * r8   arg4
 * r9   arg5
 * r11  eflags for syscall/sysret, temporary for C
 * r12-r15,rbp,rbx saved by C code, not touched.
 *
 * Interrupts are off on entry.
 * Only called from user space.
 */

// put these in /usr/include/asm-x86_64/unistd.h at the end,
// just before the #endif /* _ASM_X86_64_UNISTD_H_ */

#define __syscall_return(type, res) \
do { \
	if ((unsigned long)(res) >= (unsigned long)(-125)) { \
		errno = -(res); \
		res = -1; \
	} \
	return (type) (res); \
} while (0)

#define _syscall0(type,name) \
type name(void) \
{ \
long __res; \
__asm__ volatile ("syscall" \
	: "=a" (__res) \
	: "0" (__NR_##name)); \
__syscall_return(type,__res); \
}

#define _syscall1(type,name,type1,arg1) \
type name(type1 arg1) \
{ \
long __res; \
__asm__ volatile ("syscall" \
	: "=a" (__res) \
	: "0" (__NR_##name),"D" ((long)(arg1))); \
__syscall_return(type,__res); \
}

#define _syscall2(type,name,type1,arg1,type2,arg2) \
type name(type1 arg1,type2 arg2) \
{ \
long __res; \
__asm__ volatile ("syscall" \
	: "=a" (__res) \
	: "0" (__NR_##name),"D" ((long)(arg1)),"S" ((long)(arg2))); \
__syscall_return(type,__res); \
}

#define _syscall3(type,name,type1,arg1,type2,arg2,type3,arg3) \
type name(type1 arg1,type2 arg2,type3 arg3) \
{ \
long __res; \
__asm__ volatile ("syscall" \
	: "=a" (__res) \
	: "0" (__NR_##name),"D" ((long)(arg1)),"S" ((long)(arg2)), \
		  "d" ((long)(arg3))); \
__syscall_return(type,__res); \
}