#include <stdint.h>

#include <Processes.h>
#include <Sound.h>
#include <Memory.h>
#include <OSUtils.h>


int main(int argc, char* argv[]);

struct flat_hdr {
	char magic[4];
	unsigned long rev;          /* version */
	unsigned long entry;        /* Offset of first executable instruction
	                               with text segment from beginning of file */
	unsigned long data_start;   /* Offset of data segment from beginning of
	                               file */
	unsigned long data_end;     /* Offset of end of data segment
	                               from beginning of file */
	unsigned long bss_end;      /* Offset of end of bss segment from beginning
	                               of file */

	/* (It is assumed that data_end through bss_end forms the bss segment.) */

	unsigned long stack_size;   /* Size of stack, in bytes */
	unsigned long reloc_start;  /* Offset of relocation records from
	                               beginning of file */
	unsigned long reloc_count;  /* Number of relocation records */
	unsigned long flags;       
	unsigned long filler[6];    /* Reserved, set to zero */
};

typedef void (*voidFunction)(void);

extern void __init_section(void);
extern void __init_section_end(void);
extern void __fini_section(void);
extern void __fini_section_end(void);


void _start()
{
	
	long virtualstart, realstart;
	
	__asm__( "move.l #_start, %0" : "=r"(virtualstart) );
	__asm__( "lea (_start:w,%%pc), %0" : "=a"(realstart) );
	
	long displacement = realstart - virtualstart; 
	
	struct flat_hdr *header = (struct flat_hdr*) (displacement - 0x40);
	
	SysEnvRec env;
	long bss_size;
	Ptr bss;
	
	env.processor = 0;
	__asm__ __volatile__ (
            "move.w #2, %%d0\n\t"	// versionRequested
            "lea %0, %%a0\n\t"		// &env
            "dc.w 0xa090\n\t"		// _SysEnvirons
        : 
	    : "m"(env)
        : "%a0", "%a1", "%d0", "%d1", "%d2", "memory", "cc"
    );
	
	bss_size = header->bss_end - header->data_end;
	//Ptr bss = NewPtrClear(bss_size);
	__asm__ __volatile__ (
            "move.l %1, %%d0\n\t"
            "dc.w 0xa31e\n\t"	// _NewPtrClear
            "move.l %%a0 , %0\n\t"
        : "=g"(bss)
        : "g"(bss_size)
        : "%a0", "%a1", "%d0", "%d1", "%d2", "memory", "cc"
    );

	long n = header->reloc_count;
	long *relocs = (long*)( (char*)header + header->reloc_start );
	long i;
	long data_end = header->data_end - 0x40;
	long bss_displacement = (long)bss - data_end;
	
	for(i = 0; i < n; i++)
	{
		uint8_t *addrPtr = (uint8_t*)(relocs[i] + displacement);
		long addr;
		
		addr = (addrPtr[0] << 24) | (addrPtr[1] << 16) | (addrPtr[2] << 8) | addrPtr[3];
		
		addr += addr >= data_end ? bss_displacement : displacement;
		
		addrPtr[0] = addr >> 24;
		addrPtr[1] = addr >> 16;
		addrPtr[2] = addr >> 8;
		addrPtr[3] = addr;
	}
	if(env.processor >= env68040)
	{
		__asm__ __volatile__ ("dc.w 0xa0bd" : : : "%a0", "%a1", "%d0", "%d1", "%d2", "cc"); // FlushCache();
	}
	{
		char *p = (char*)&__init_section;
		char *e = (char*)&__init_section_end;
		p += 2;
		while( p < e )
		{
			(*(voidFunction)(*(long*)p))();
			p += 6;
		}
	}
	
	{
		char *argv[2] = { "./a.out", NULL };
		main(1, argv);
	}
	ExitToShell();
}