note_corewar.txt

                                
**************************************************************  
*                                                            *
 *                          COREWAR                         *      
*                                                            *      
**************************************************************      
                                        

********************************  
*           SUMMARY            *      
********************************      

GENERAL:
- register-based process VM
- 1 joueur = 1 champion = 1 ou + processus
- 1 cycle = tous les processus font une action

EACH PROCESS:
	- 16 registres de 4 octets
	- 1 PC (contient l'adresse de la next op du process) 
	- 1 carry - vaut 1 si derniere op reussie  

PLAYER NUMBER:
  - soit specifié par la VM en fonction de l'ordre des argv
  - soit specifié en option

CHAMPION INIT: 
  - r1 = num player (sert pour le live)
  - autres rx = 0
  - sauf le PC

CHAMPION LOADING: 
  - espacer equitablement leur point d'entrée
  - size du champion doit etre <= MAX_CHAMP_SIZE (p7)

ARENA MEMORY:
  - malloc MEM_SIZE 
  - memoire est circulaire
  - l'adressage commence a 0 

LIVE MANAGEMENT: 
  - tous les CYCLE_TO_DIE (1536) check si le champion a emis 
  au moins 1 LIVE depuis le dernier check
  - else, kill le process 
  - compteur de LIVE a chaque check (live_count)
  - if (live_count >= NBR_LIVE)
  	CYCLE_TO_DIE = CYCLE_TO_DIE - CYCLE_DELTA
  - a chaque LIVE emis, print "un processus dit que... "
  - si on a pas decrementé CYCLE_TO_DIE depuis MAX_CHECKS (nb_checks)
  	if (nb_checks == MAX_CHECKS) 
  		CYCLE_TO_DIE = CYCLE_TO_DIE - CYCLE_DELTA
  		nb_checks = 0
  - LIVE doit etre fait avec le num du player
  possibilite de faire des LIVE d'autres players 

END OF GAME: 
  - quand il n'y a plus de process en vie
  - main loop du programme ? 
  	while (live_count)
  		while (i < CYCLE_TO_DIE) 		

WINNER OF GAME: 
  - dernier champion a avoir emis LIVE
  - variable last_live = num player ? 
  - print win statement "le joueur x(champion_name) a gagne" 

ERROR HANDLING:
  - afficher les erreurs sur stderr (fd = 2)

USAGE: 
  - ./corewar [-dump nb_cycles] [[-n number] champion1.cor] ...

MEMORY DUMP: 
  - dump memoire en hexa - 32 octets par ligne 


CARRY: instr. qui le modifient en cas d'echec: 
	
BIG ENDIANNESS:
	- voir : https://chortle.ccsu.edu/AssemblyTutorial/Chapter-15/ass15_3.html
	- https://betterexplained.com/articles/understanding-big-and-little-endian-byte-order/
	- to check computer Endianness
		#include <stdio.h>
		int main(void)	{
		    unsigned int x = 1;		    
			(((char *)&x)[0]) == 1 ? printf("Big Endian\n") 
			: printf("Little Endian\n");
			 return (0);
		}

VM: 
  - Save opcode during the first cycle
  - Execute the operation at the end of the cast time
	- using the saved opcode (even if the memory is different now) 
	- use the current parameters / args 
  - Error : If the parameters are now invalid
	- do nothing, and move the opcode one cell further






Doubts: 
=======
- .name .comment chargé dans l'arene ? 														## No
- carry modifier en cas d'echec d'op - qu'est qu'un echec ? 
- num player commence a 0 ou 1 ? 															## 1
- que signifie kill le process (p6) ? 
- NBR_LIVE = MAX LIVES emis par un seul champion ou le total des LIVES emis par tous ? 
- voir le format exact du dump sur la VM 42
- CHAMP_MAX_SIZE inclut-il .name .comment ? (probablement pas)								## No



To try:
=======
[ ] checker les options de l'ASM, Corewar
[ ] nm les fonctions de corewar
[ ] checker les memory dump de corewar


********************************  
*          Structure           *      
********************************      

VM Setup 
	- getopt - parsing des options
	- get players
		- input error handling
	- generate arena
	- read & init process
	- load process 

Main loop	
	- cycle - while (process alive)
	- update VM parameters - every x cycles
	- update process - every cycle
		- launch each process op - when ready (not casting)
			- update arena/VM
		- kill and fork process - when necessary

Select Winner 
	- print last Live Player/champion  

Clean VM 
	- free process
	- free vm 
	- free players 	
		  
	



********************************  
*             To do            *      
********************************      

Player input
	[x] ERROR - Invalid name extension .cor
	[x] ERROR - Too big program
	[x] ERROR - Wrong chmod permission denied 
	[x] ERROR - Can't open the file - read return 
	[x] ERROR - Wrong exec_magic - file type 
	[x] ERROR - Too many players - MAX_PLAYERS  
	[ ] Automatic player numbering
	[ ] Getopt support 



********************************  
*             misc.            *      
********************************      

Translator : Assembler language application (p22)
IR : Intermediate Representation 
VM : Stack-based Bytecode interpreter (p26)

Assembler IR : AST -> Abstract Syntax Tree
LL Recursive Descent Parser
Syntax Directed Translator (p26/p36) -> Allow a fast and easy translation
Bytecode Assembler (p265)


                                
**************************************************************  
*                                                            *
 *                          ASM                             *      
*                                                            *      
**************************************************************  

********************************  
*             header           *      
******************************** 

if Symbol == .
	if Label == name
		if String
			encode String
		else
			ERROR
	else
		ERROR
else
	ERROR

if Symbol == .
	if Label == comment
		if String
			encode String
		else
			ERROR
	else
		ERROR
else
	ERROR

********************************  
*             opcode           *      
******************************** 

if Label
	if Symbol == :
		continue
	else
		ERROR
else if Keyword
	foreach args in op_tab separated by Symbol == ,
		if Arguments get != Argument require
			ERROR
		else
			encode
else
	ERROR

********************************  
*             args             *      
******************************** 

if Symbol == %
	if Symbol == :
		if Label exist
			encode Direct Label
		else
			ERROR
	else if Symbol == = || Symbol == +
		if Number
			encore Direct Number
		else
			ERROR
	else if Number
		encode Direct Number
	else
		ERROR
else if Symbol == - || Symbol == +
	if Number
		encode Indirect Number
	else
		ERROR
else if Number
	encode Indirect Number
else if Register
	encode Register

********************************  
*             deasm            *      
******************************** 

Parse Header -> Easy
	name start at 4
	comment start at name.max + 8
Program start at name.max + comment.max + 8
while opcode = read(4)
	if opcode.octal
		args_type = read(1)
		res = args_type >> 6 & 0b11
			if res = T_IND
				read(2)
			else if res = T_DIR
				read(opcode.label ? 2 : 4)
			else
				read(1)
		res = args_type >> 4 & 0b11
			SAME
		res = args_type >> 2 & 0b11
			SAME
		res = args_type >> 0 & 0b11 #-- Always false