/*
   ============================================================================
	booter.c -- load an absolute format Alcyon object file
	Version 18 -- 1987-11-06 -- D.N. Lynx Crowe
   ============================================================================
*/

#define	PRINTIT	1	/* define non-zero to get printf output from booter */

#include "stdio.h"
#include "io.h"
#include "stddefs.h"
#include "portab.h"
#include "objdefs.h"
#include "biosdefs.h"

extern	FILE	*fopenb(int8_t *name, int8_t *mode);
extern	int16_t	fclose(FILE *ptr);
extern	int16_t	fread(int8_t *buffer, uint16_t size, int16_t number, FILE *stream);
extern	int16_t	flread(int8_t *buff, int32_t len, FILE *fp);
extern	int32_t	getl(FILE *stream);

#if	PRINTIT
extern	struct	fcb	*SnapFCB(struct fcb *fcp);
extern	int16_t	ClusMap(struct fcb *fcp);

extern	int16_t waitcr(void);
#endif

static FILE	*B_file;		/* boot file pointer */

struct	EXFILE B_fhdr;	/* executable file header */

int32_t	B_txt_o,	/* test origin from file header */
	B_dat_o,	/* data origin from file header */
	B_bss_o,	/* bss origin from file header */
	B_txt_l,	/* text length from file header */
	B_dat_l,	/* data length from file header */
	B_bss_l,	/* bss length from file header */
	B_lod_l,	/* total data length loaded */
	B_end,		/* end address */
	B_chk;		/* checksum */

int8_t	*B_buf_a;	/* boot load address */

int16_t	B_log_s;	/* boot log switch */
int16_t	B_dbg_s;	/* boot debug switch */

/*  */

/*
   ============================================================================
	booter(fn, textadr) -- load file named by string 'fn' at 'textadr'.
	If 'textadr' is 0, the text origin from the file will be used.
	Returns 0 if load was OK, non-zero error code otherwise.
   ============================================================================
*/

int16_t booter(int8_t *fn, int32_t textadr)
{
	register int32_t i, bgnbss, endbss;
	register int8_t *cp;
#if	PRINTIT
	register struct fcb *fcp;
#endif

	/* initialize the origins and lengths to 0 */

	B_txt_o = 0L;
	B_dat_o = 0L;
	B_bss_o = 0L;
	B_txt_l = 0L;
	B_dat_l = 0L;
	B_bss_l = 0L;
	B_lod_l = 0L;

	/* open the file */

	if (NULL EQ (B_file = fopenb(fn, "r"))) {

#if	PRINTIT
		if (B_log_s)
			printf("booter:  Unable to open \042%s\042\n", fn);
#endif
		return(1);
	}

#if	PRINTIT
	if (B_dbg_s) {		/* if we're debugging, print the FCB stuff */

		fcp = (struct fcb *)(chantab[B_file->_unit].c_arg);

		SnapFCB(fcp);
		ClusMap(fcp);
		waitcr();
	}
#endif

	/* read in the file header */

	if (1 NE fread(&B_fhdr, sizeof B_fhdr, 1, B_file)) {

#if	PRINTIT
		if (B_log_s)
			printf("booter:  Unable to read header for \042%s\042\n", fn);
#endif
		fclose(B_file);
		return(2);
	}

	/* check the magic */

	if ((B_fhdr.F_Magic NE F_R_C) AND (B_fhdr.F_Magic NE F_R_D)) {

#if	PRINTIT
		if (B_log_s)
			printf("booter:  Bad magic [0x%04x] in file \042%s\042",
				B_fhdr.F_Magic, fn);
#endif
		fclose(B_file);
		return(3);
	}

/* 
*/

	/* if it's a discontinuous file, read the origins */

	if (B_fhdr.F_Magic EQ F_R_D) {

		B_dat_o = getl(B_file);
		B_bss_o  = getl(B_file);
	}

	B_txt_o = B_fhdr.F_Res2;

	B_buf_a = textadr ? textadr : B_txt_o;
	B_lod_l = B_fhdr.F_Text + B_fhdr.F_Data;

	if (0 NE flread(B_buf_a, B_lod_l, B_file)) {
	
#if	PRINTIT
		if (B_log_s)
			printf("booter:  Unable to read \042%s\042\n", fn);
#endif
		fclose(B_file);
		return(4);
	}

	B_end = B_buf_a + B_lod_l - 1L;

	B_txt_l = B_fhdr.F_Text;
	B_dat_l = B_fhdr.F_Data;
	B_bss_l = B_fhdr.F_BSS;

	cp    = B_buf_a;	/* calculate checksum */
	B_chk = 0L;

	for (i = 0; i < B_lod_l; i++)
		B_chk += *cp++ & 0x000000FFL;

	if (B_bss_o)
		bgnbss = B_bss_o;
	else
		bgnbss = B_end + 1L;

		endbss = bgnbss + B_bss_l - 1L;

#if	PRINTIT
	if (B_log_s) {

		printf("File \042%s\042 loaded from $%08lX to $%08lX\r\n",
			fn, B_buf_a, B_end);
		printf("   BSS $%08lX to $%08lX\r\n", bgnbss, endbss);
		printf("Checksum   = $%08lX, Load length = %ld ($%08lX)\r\n",
			B_chk, B_lod_l, B_lod_l);
		printf("   B_txt_o = $%08lX, B_dat_o = $%08lX, B_bss_o = $%08lX\r\n",
			B_txt_o, B_dat_o, B_bss_o);
		printf("   B_txt_l = $%08lX, B_dat_l = $%08lX, B_bss_l = $%08lX\r\n",
			B_txt_l, B_dat_l, B_bss_l);
	}
#endif

	fclose(B_file);
	return(0);
}