PDP-11 a.out binary C Mac

header.c

/*
  cc header.c -o header
*/

#include <stdio.h>
#include <stdint.h>

uint8_t mem[0x10000];

/**************************************************/
// Little Endian
/**************************************************/
uint16_t w_l_uint16(int i){
	return mem[i] | (mem[i + 1] << 8);
}

/**************************************************/
// Big Endian
/**************************************************/
uint16_t w_s_uint16(int i){
	return ( mem[i] << 8 ) | mem[i + 1] ;
}

/**************************************************/

/**************************************************/
int ana_text(int tsize)
{
	uint16_t w0, w1;

	for (int i = 0; i < tsize; i += 2) {
		w0 = w_l_uint16(i) ;
		switch (w0){
		  case 0x15c0 :
			w1 = w_l_uint16(i+2) ;
			printf("%2x: 15c0 %04x \t mov $%d, r0 \n",i,w1,w1);
			i += 2;
			break;
		  case 0x8904 :
			// write
			printf("%2x: %04x  \t sys  4\n",i,w0);
			i += 2;
			w1 = w_l_uint16(i) ;
			// word
			printf("%2x: %04x \t word  %o \n",i,w1,w1);
			i += 2;
			w1 = w_l_uint16(i) ;
			// rtt
			printf("%2x: %04x \t rtt \n",i,w1);
			break;
		  case 0x8901 :
			printf("%2x: %04x \t sys  1\n",i,w0);
			break;
		  default:
			printf("%2x:  error %04x \n",i,w0);
			break;
		}
	}

	return 0 ;

}
/**************************************************/

/**************************************************/
int main(int argc, char *argv[]) {
	FILE *f;
	uint8_t header[16];
	uint16_t w ;
	int tsize, dsize;

	// command line
	if (argc != 2) {
		printf("Command Line Error !\n");
		return 1;
	}
	// file open
	f = fopen(argv[1], "rb");
	if (!f) {
		printf("file not fund!\n");
		return 1;
	}
	// read header area
	fread(header, sizeof(header), 1, f);
	// text size
	w = header[2] | (header[3] << 8);
	tsize = w ;
	// data size
	w = header[4] | (header[5] << 8);
	dsize = w ;
	printf("tsize = 0x%04x, dsize = 0x%04x\n", tsize, dsize);

	// read text & data area
	fread(mem, tsize + dsize, 1, f);
	fclose(f);

	// .text
	printf("session: .text \n");
	ana_text(tsize);

	// .data
	printf("session: .data\n");
	for (int i = tsize; i < tsize + dsize; i += 2) {
		w = w_s_uint16(i);
		printf("%04x: %04x\n", i, w);
	}

	return 0;
}