/* 08/07/01	Console app to patch Codewarrior PS-X EXE's to run on emulators etc,
	 based on the code from Andrew Kieschnick's eco2exe. The patching adds two mips 
	 jump instructions at the end of the file, the first is an address in system 
	 memory, the second is the exe's start address. The first address is jumped to 
	 at the start of program execution, when it returns the original start address 
	 is executed. The pc0 and t_size values are altered accordingly */
	 
/* includes */
#include	"windows.h"
#include	"stdio.h"
#include	"string.h"
#include	"conio.h"

int Openfile(int	argc, char *fname);

/* globals */
FILE			*file_p;
char			str[8];

struct
{
	unsigned	long	pc0, dummy, start_addr, size;
}data;

struct
{
	unsigned long		sysjump, nop, oldpc0, nop2;
}mips = {0x0C00400C};													/* jal 0x80010030 */


void main(int	argc, char *argv[])
{
	
	printf("\t\tCodeWarrior PS-X EXE File Patcher\n");

	if(Openfile(argc, argv[1]))				/* attempt to open file */
	{
		fseek(file_p, 16, SEEK_SET);		/* seek to pc0 */

		/* read in required values, we don't need 2nd */
		fread(&data, 4, 4, file_p);

		mips.oldpc0 = data.pc0;						/* keep original start address */

		data.pc0 = data.start_addr + data.size;			/*  new code added at end of exe */
		
		data.size += 16;								/* exe size increased */

		/* write new pc0 and size back to file */
		fseek(file_p, 16, SEEK_SET);
		fwrite(&data, 4, 4, file_p);

		/* add jump address instructions to exe end */
		fseek(file_p, 0, SEEK_END);

		/* create instruction to jump to original start address */
		mips.oldpc0 = 0x08000000 + ((mips.oldpc0&0x03ffffff)>>2);		
		fwrite(&mips, 4, 4, file_p);
		
		printf("File patched.\n");

		fclose(file_p);

		Sleep(1500);
	}
	
}
		

/* attempt to open file, check it's a CW exe */
int Openfile(int	argc, char *fname)
{
	if(argc == 2)
	{
		if(file_p = fopen(fname, "rb+"))
		{
			fread(str, 1, 4, file_p);					/* read in PS-X at start of exe */

			if(!strcmp(str, "PS-X"))
				return 1;
			else
			{
				printf("Not a PS-X EXE file.\n");
				fclose(file_p);
			}
		}
		else
			printf("Cannot open file.\n");
	}
	else
		printf("Syntax:	cwpatch <file name>\n");

	while(!kbhit())
		Sleep(100);

	return 0;
}