/*******************************************************************************/
/* COS2000 - Compatible Operating System - LGPL v3 - Hordé Nicolas             */
/*                                                                             */

#include "types.h"
#include "interrupts.h"
#include "memory.h"

#define MAXPIDVALUE	    0xFFFF
#define MAXNUMPROCESS	256

#define STATUS_FREE   0x0
#define STATUS_ZOMBIE 0xFF
#define STATUS_READY  0xF0
#define STATUS_RUN    0x1
#define STATUS_SLEEP  0x2

/* ELF type */
#define ET_NONE 	0	//No file type
#define ET_REL 	    1		//Relocatable file
#define ET_EXEC 	2	//Executable file
#define ET_DYN 	    3		//Shared object file
#define ET_CORE 	4	//Core file
#define ET_LOOS 	0xfe00	//Operating system-specific
#define ET_HIOS 	0xfeff	//Operating system-specific
#define ET_LOPROC 	0xff00	//Processor-specific
#define ET_HIPROC 	0xffff	//Processor-specific

/* ELF identification */
#define	EI_MAG0		    0	//File identification
#define	EI_MAG1		    1	//File identification
#define	EI_MAG2		    2	//File identification
#define	EI_MAG3		    3	//File identification
#define	EI_CLASS	    4	//File class
#define	EI_DATA		    5	//Data encoding
#define	EI_VERSION	    6	//File version
#define	EI_OSABI 	    7	//Operating system/ABI identification
#define	EI_ABIVERSION 	8	//ABI version
#define	EI_PAD 	        9	//Start of padding bytes
#define	EI_NIDENT 	    16	//Size of e_ident[]

/* ELF version */
#define EV_NONE 	0	//Invalid version
#define EV_CURRENT 	1	//Current version

/* ELF machine type */

#define EM_NONE     0		//No machine
#define EM_386 	    3		//Intel 80386
#define EM_IA_64 	50	//Intel IA-64 processor architecture
#define EM_X86_64 	62	//AMD x86-64 architecture

/* EI signature */
#define	ELFMAG0		0x7f
#define	ELFMAG1		'E'
#define	ELFMAG2		'L'
#define	ELFMAG3		'F'

/* EI file class  */
#define	ELFCLASSNONE	0	/* invalid class */
#define	ELFCLASS32	    1	/* 32-bit objects */
#define	ELFCLASS64	    2	/* 64-bit objects */

/* EI data structure */
#define	ELFDATANONE	0	/* invalide data encoding */
#define	ELFDATA2LSB	1	/* least significant byte first (0x01020304 is 0x04 0x03 0x02 0x01) */
#define	ELFDATA2MSB	2	/* most significant byte first (0x01020304 is 0x01 0x02 0x03 0x04) */

/* p type */
#define	PT_NULL             0
#define	PT_LOAD             1
#define	PT_DYNAMIC          2
#define	PT_INTERP           3
#define	PT_NOTE             4
#define	PT_SHLIB            5
#define	PT_PHDR             6
#define	PT_LOPROC  0x70000000
#define	PT_HIPROC  0x7fffffff

/* p flags */
#define PF_X	0x1
#define PF_W	0x2
#define PF_R	0x4

/* OS identification */
#define ELFOSABI_NONE 	0	//No extensions or unspecified
#define ELFOSABI_LINUX 	3	//Linux
#define ELFOSABI_COS2000 16	//COS2000

/* ELF header */
typedef struct elf32
{
	u8      e_ident[EI_NIDENT];
	u16     e_type;
	u16     e_machine;
	u32     e_version;
	u8     *e_entry;
	u32     e_phoff;
	u32     e_shoff;
	u32     e_flags;
	u16     e_ehsize;
	u16     e_phentsize;
	u16     e_phnum;
	u16     e_shentsize;
	u16     e_shnum;
	u16     e_shstrndx;
} elf32;

typedef struct elf32p
{
	u32     p_type;
	u32     p_offset;
	u8     *p_vaddr;
	u8     *p_paddr;
	u32     p_filesz;
	u32     p_memsz;
	u32     p_flags;
	u32     p_align;
} elf32p;


typedef struct stackdef
{
	u32     esp0;
	u16     ss0;
} stackdef __attribute__ ((packed));


typedef struct process
{
	u32     pid;
	bool    kernel;
	regs    dump;
	stackdef kstack;
	pd     *pdd;
	u32     result;
	u8      status;
	u8     *exec_low;
	u8     *exec_high;
	u8     *bss_low;
	u8     *bss_high;
	struct process *parent;
	page_t  page_head;
	u32     entry;
} process __attribute__ ((packed));

u32     getcurrentpid();
void    task_init();
u32     task_getfreePID();
u32     task_usePID(u32 pid);
u32     task_create(u8 * code, bool kerneltask);
u32     elf_test(u8 * src);
u32     elf_load(u8 * src, u32 pid);
void    task_switch(u32 pid, bool fromkernelmode);
process *getcurrentprocess();
void    task_run(u32 pid);