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/*

 * misc.c

 *

 * This is a collection of several routines from gzip-1.0.3

 * adapted for Linux.

 *

 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994

 * puts by Nick Holloway 1993, better puts by Martin Mares 1995

 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996

 */

#include <asm/segment.h>

#include <asm/io.h>

#include <linux/types.h>

/*

 * gzip declarations

 */

#define OF(args)  args

#define STATIC static

void* memset(void* s, int c, size_t n);

void* memcpy(void* __dest, __const void* __src,

             size_t __n);

#define memzero(s, n)     memset ((s), 0, (n))

typedef unsigned char  uch;

typedef unsigned short ush;

typedef unsigned long  ulg;

#define WSIZE 0x8000            /* Window size must be at least 32k, */

                                /* and a power of two */

static uch *inbuf;           /* input buffer */

static uch window[WSIZE];    /* Sliding window buffer */

static unsigned insize = 0;  /* valid bytes in inbuf */

static unsigned inptr = 0;   /* index of next byte to be processed in inbuf */

static unsigned outcnt = 0;  /* bytes in output buffer */

/* gzip flag byte */

#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */

#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */

#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */

#define ORIG_NAME    0x08 /* bit 3 set: original file name present */

#define COMMENT      0x10 /* bit 4 set: file comment present */

#define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */

#define RESERVED     0xC0 /* bit 6,7:   reserved */

#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())

/* Diagnostic functions */

#ifdef DEBUG

#  define Assert(cond,msg) {if(!(cond)) error(msg);}

#  define Trace(x) fprintf x

#  define Tracev(x) {if (verbose) fprintf x ;}

#  define Tracevv(x) {if (verbose>1) fprintf x ;}

#  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}

#  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}

#else

#  define Assert(cond,msg)

#  define Trace(x)

#  define Tracev(x)

#  define Tracevv(x)

#  define Tracec(c,x)

#  define Tracecv(c,x)

#endif

static int  fill_inbuf(void);

static void flush_window(void);

static void error(char *m);

static void gzip_mark(void **);

static void gzip_release(void **);

/*

 * These are set up by the setup-routine at boot-time:

 */

struct screen_info {

        unsigned char  orig_x;

        unsigned char  orig_y;

        unsigned char  unused1[2];

        unsigned short orig_video_page;

        unsigned char  orig_video_mode;

        unsigned char  orig_video_cols;

        unsigned short unused2;

        unsigned short orig_video_ega_bx;

        unsigned short unused3;

        unsigned char  orig_video_lines;

        unsigned char  orig_video_isVGA;

};

/*

 * This is set up by the setup-routine at boot-time

 */

#define EXT_MEM_K (*(unsigned short *)0x90002)

#ifndef STANDARD_MEMORY_BIOS_CALL

#define ALT_MEM_K (*(unsigned long *) 0x901e0)

#endif

#define DRIVE_INFO (*(struct drive_info *)0x90080)

#define SCREEN_INFO (*(struct screen_info *)0x90000)

#define RAMDISK_SIZE (*(unsigned short *)0x901F8)

#define ORIG_ROOT_DEV (*(unsigned short *)0x901FC)

#define AUX_DEVICE_INFO (*(unsigned char *)0x901FF)

extern char input_data[];

extern int input_len;

static long bytes_out = 0;

static uch *output_data;

static unsigned long output_ptr = 0;

static void *malloc(int size);

static void free(void *where);

static void error(char *m);

static void gzip_mark(void **);

static void gzip_release(void **);

static void puts(const char *);

extern int end;

static long free_mem_ptr = (long)&end;

static long free_mem_end_ptr = 0x90000;

#define INPLACE_MOVE_ROUTINE  0x1000

#define LOW_BUFFER_START      0x2000

#define LOW_BUFFER_END       0x90000

#define LOW_BUFFER_SIZE      ( LOW_BUFFER_END - LOW_BUFFER_START )

#define HEAP_SIZE             0x2000

static int high_loaded =0;

static uch *high_buffer_start /* = (uch *)(((ulg)&end) + HEAP_SIZE)*/;

static char *vidmem = (char *)0xb8000;

static int vidport;

static int lines, cols;

#include "../../../../lib/inflate.c"

static void *malloc(int size)

{

        void *p;

        if (size <0) error("Malloc error\n");

        if (free_mem_ptr <= 0) error("Memory error\n");

        free_mem_ptr = (free_mem_ptr + 3) & ~3; /* Align */

        p = (void *)free_mem_ptr;

        free_mem_ptr += size;

        if (free_mem_ptr >= free_mem_end_ptr)

                error("\nOut of memory\n");

        return p;

}

static void free(void *where)

{       /* Don't care */

}

static void gzip_mark(void **ptr)

{

        *ptr = (void *) free_mem_ptr;

}

static void gzip_release(void **ptr)

{

        free_mem_ptr = (long) *ptr;

}

static void scroll()

{

        int i;

        memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 );

        for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 )

                vidmem[i] = ' ';

}

static void puts(const char *s)

{

        int x,y,pos;

        char c;

        x = SCREEN_INFO.orig_x;

        y = SCREEN_INFO.orig_y;

        while ( ( c = *s++ ) != '\0' ) {

                if ( c == '\n' ) {

                        x = 0;

                        if ( ++y >= lines ) {

                                scroll();

                                y--;

                        }

                } else {

                        vidmem [ ( x + cols * y ) * 2 ] = c;

                        if ( ++x >= cols ) {

                                x = 0;

                                if ( ++y >= lines ) {

                                        scroll();

                                        y--;

                                }

                        }

                }

        }

        SCREEN_INFO.orig_x = x;

        SCREEN_INFO.orig_y = y;

        pos = (x + cols * y) * 2;       /* Update cursor position */

        outb_p(14, vidport);

        outb_p(0xff & (pos >> 9), vidport+1);

        outb_p(15, vidport);

        outb_p(0xff & (pos >> 1), vidport+1);

}

void* memset(void* s, int c, size_t n)

{

        int i;

        char *ss = (char*)s;

        for (i=0;i<n;i++) ss[i] = c;

}

void* memcpy(void* __dest, __const void* __src,

                            size_t __n)

{

        int i;

        char *d = (char *)__dest, *s = (char *)__src;

        for (i=0;i<__n;i++) d[i] = s[i];

}

/* ===========================================================================

 * Fill the input buffer. This is called only when the buffer is empty

 * and at least one byte is really needed.

 */

static int fill_inbuf()

{

        if (insize != 0) {

                error("ran out of input data\n");

        }

        inbuf = input_data;

        insize = input_len;

        inptr = 1;

        return inbuf[0];

}

/* ===========================================================================

 * Write the output window window[0..outcnt-1] and update crc and bytes_out.

 * (Used for the decompressed data only.)

 */

static void flush_window_low()

{

    ulg c = crc;         /* temporary variable */

    unsigned n;

    uch *in, *out, ch;

    in = window;

    out = &output_data[output_ptr];

    for (n = 0; n < outcnt; n++) {

            ch = *out++ = *in++;

            c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);

    }

    crc = c;

    bytes_out += (ulg)outcnt;

    output_ptr += (ulg)outcnt;

    outcnt = 0;

}

static void flush_window_high()

{

    ulg c = crc;         /* temporary variable */

    unsigned n;

    uch *in,  ch;

    in = window;

    for (n = 0; n < outcnt; n++) {

        ch = *output_data++ = *in++;

        if ((ulg)output_data == LOW_BUFFER_END) output_data=high_buffer_start;

        c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);

    }

    crc = c;

    bytes_out += (ulg)outcnt;

    outcnt = 0;

}

static void flush_window()

{

        if (high_loaded) flush_window_high();

        else flush_window_low();

}

static void error(char *x)

{

        puts("\n\n");

        puts(x);

        puts("\n\n -- System halted");

        while(1);       /* Halt */

}

#define STACK_SIZE (4096)

long user_stack [STACK_SIZE];

struct {

        long * a;

        short b;

        } stack_start = { & user_stack [STACK_SIZE] , KERNEL_DS };

void setup_normal_output_buffer()

{

#ifdef STANDARD_MEMORY_BIOS_CALL

        if (EXT_MEM_K < 1024) error("Less than 2MB of memory.\n");

#else

        if ((ALT_MEM_K > EXT_MEM_K ? ALT_MEM_K : EXT_MEM_K) < 1024) error("Less than 2MB of memory.\n");

#endif

        output_data = (char *)0x100000; /* Points to 1M */

}

struct moveparams {

        uch *low_buffer_start;  int lcount;

        uch *high_buffer_start; int hcount;

};

void setup_output_buffer_if_we_run_high(struct moveparams *mv)

{

        high_buffer_start = (uch *)(((ulg)&end) + HEAP_SIZE);

#ifdef STANDARD_MEMORY_BIOS_CALL

        if (EXT_MEM_K < (3*1024)) error("Less than 4MB of memory.\n");

#else

        if ((ALT_MEM_K > EXT_MEM_K ? ALT_MEM_K : EXT_MEM_K) < (3*1024)) error("Less than 4MB of memory.\n");

#endif

        mv->low_buffer_start = output_data = (char *)LOW_BUFFER_START;

        high_loaded = 1;

        free_mem_end_ptr = (long)high_buffer_start;

        if ( (0x100000 + LOW_BUFFER_SIZE) > ((ulg)high_buffer_start)) {

                high_buffer_start = (uch *)(0x100000 + LOW_BUFFER_SIZE);

                mv->hcount = 0; /* say: we need not to move high_buffer */

        }

        else mv->hcount = -1;

        mv->high_buffer_start = high_buffer_start;

}

void close_output_buffer_if_we_run_high(struct moveparams *mv)

{

        mv->lcount = bytes_out;

        if (bytes_out > LOW_BUFFER_SIZE) {

                mv->lcount = LOW_BUFFER_SIZE;

                if (mv->hcount) mv->hcount = bytes_out - LOW_BUFFER_SIZE;

        }

        else mv->hcount = 0;

}

int decompress_kernel(struct moveparams *mv)

{

        if (SCREEN_INFO.orig_video_mode == 7) {

                vidmem = (char *) 0xb0000;

                vidport = 0x3b4;

        } else {

                vidmem = (char *) 0xb8000;

                vidport = 0x3d4;

        }

        lines = SCREEN_INFO.orig_video_lines;

        cols = SCREEN_INFO.orig_video_cols;

        if (free_mem_ptr < 0x100000) setup_normal_output_buffer();

        else setup_output_buffer_if_we_run_high(mv);

        makecrc();

        puts("Uncompressing Linux...");

        gunzip();

        puts("done.\nNow booting the kernel\n");

        if (high_loaded) close_output_buffer_if_we_run_high(mv);

        return high_loaded;

}