fdi baltik

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

FILE * fi;
FILE * fo;

typedef char                s8;
typedef unsigned char       u8;
typedef unsigned short int  u16;
typedef unsigned long int   u32;

typedef struct {
    s8 fdi[3];
    u8 ro;
    u16 c;
    u16 h;
    u16 txt;
    u16 data;
    u16 ext_size;
}FDIHEAD;

struct FDISECTOR{
    u8 c;
    u8 h;
    u8 s;
    u8 n;
    u8 flag;
    u16 offs;
} __attribute__((packed));

// __attribute__((packed))
struct FDITRACK{
    u32 offs;
    u16 dump;
    u8 secs;
} __attribute__((packed));

FDIHEAD fdihead;
//FDITRACK * ts[160];
long int ss[80 * 2 * 5];
u8 fdi[42 * 160];

u8 regs[1024];
u8 buf[48 * 1024 + 27];
s8 fname[256];
const long int s_inc[]={-0x00001000L, 0x00000400, 0x00000400, 0x00000400, 0x00000400};

int main (int argc, char *argv[]){
    int len;
    u32 sh = 1;
    if(argc < 2){
        puts("Wrong parameters");
        return 1;
    }
    u8 * p = strrchr(argv[1],'.');
    if(!p){
        puts("Support only FDI file");
        return 1;
    }
    if((p[1]&0xdf)){
        puts("Support only FDI file");
        return 1;
    }

    puts("Baltik fdi extractor");
    if((fi=fopen(argv[1],"rb"))==NULL) {
        printf("\nImage file %s not open.\n",argv[1]);
        return 1;
    }
    fread((char*)(&fdihead), 1, sizeof(fdihead), fi);
    //printf("start data %d\n",fdihead.data);
    if(fdihead.c > 80) fdihead.c = 80;
    if(fdihead.h > 2) fdihead.h = 2;
    len = fread(fdi, 1, sizeof(fdi), fi);
    //printf("len %d\n", len);

    memset(ss, 0x0000, sizeof(ss));

    fseek(fi, fdihead.data, SEEK_SET);
    p = fdi;
    for(int i = 0; i < (fdihead.c * fdihead.h); i++){
        struct FDITRACK * t = (struct FDITRACK*)p;
        p += 7;
        //printf("t %x\n", t->offs);
        for(int j = 1; j <= t->secs; j++){
            struct FDISECTOR * s = (struct FDISECTOR*) p;
            p += 7;
            ss[s->s - 1 + s->h * 5 + s->c * 5 * 2] = fdihead.data + t->offs + s->offs;
            //printf("%d %x\n", s->s - 1 + s->h * 5 + s->c * 5 * 2, fdihead.data + t->offs + s->offs);
        }
    }
    for(int k = 1; k < 17; k++){
        fseek(fi, ss[(k - 1) * 50],SEEK_SET);
        //printf("%x ", ftell(fi));
        sprintf(fname, "%02d.sna", k);
        putchar('\n');
        puts(fname);
        fread(regs, 1, sizeof(regs), fi);
        //puts(regs + 0x0313);
        fseek(fi,0x00000c00L,SEEK_CUR);

        for(int i = 0, j = 0; i < 48; i++, j++){
            if(j == 5) j = 0;
            len = fread(buf + i * 1024 + 27, 1, 1024, fi);
            fseek(fi, s_inc[j], SEEK_CUR);
        }
        buf[0] = regs[0x0396];  //i
        buf[1] = regs[0x0366];  //hl'
        buf[2] = regs[0x0367];
        buf[3] = regs[0x0364];  //de'
        buf[4] = regs[0x0365];
        buf[5] = regs[0x0362];  //bc'
        buf[6] = regs[0x0363];
        buf[7] = regs[0x0368];  //af'
        buf[8] = regs[0x0369];
        buf[9] = regs[0x0372];  //hl
        buf[10] = regs[0x0373];
        buf[11] = regs[0x0370]; //de
        buf[12] = regs[0x0371];
        buf[13] = regs[0x036E]; //bc
        buf[14] = regs[0x036f];
        buf[15] = regs[0x036A]; //iy
        buf[16] = regs[0x036b];
        buf[17] = regs[0x036C]; //ix
        buf[18] = regs[0x036d];
        buf[19] = 0x04;         //iff2
        buf[20] = 0x00;         //R
        buf[21] = regs[0x0374]; //af
        buf[22] = regs[0x0375];
        unsigned short int sp = *((short int*)(regs + 0x0376)) - 2;
        buf[23] = sp & 0xff;    //sp
        buf[24] = (sp >> 8) & 0xff;
        buf[25] = (regs[0x0395] & 0x80) ? 2 : 1;            //IM
        buf[26] = 0x00;         //border
        buf[sp - 0x4000 + 27] =     regs[0x0378];   //PC
        buf[sp - 0x4000 + 1 + 27] = regs[0x0379];

        if((fo=fopen(fname,"wb"))==NULL) {
            printf("file 03.sna not create.\n",fname);
            return 1;
        }
        fwrite(buf, 1, sizeof(buf), fo);
        fclose(fo);
    }
    fclose(fi);
}