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// DGen/SDL v1.15+
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "md.h"
#include "decode.h"
// These are my (Joe's) functions added to the md class.
// This takes a comma or whitespace-separated list of Game Genie and/or hex
// codes to patch the ROM with.
void md::patch(const char *list)
{
static const char delims[] = " \t\n,";
char *worklist, *tok;
struct patch p;
// Copy the given list to a working list so we can strtok it
worklist = (char*)malloc(strlen(list)+1);
strcpy(worklist, list);
for(tok = strtok(worklist, delims); tok; tok = strtok(NULL, delims))
{
// If it's empty, toss it
if(*tok == '\0') continue;
// Decode it
decode(tok, &p);
// Discard it if it was bad code
if((signed)p.addr == -1) {
printf("Bad patch \"%s\"\n", tok);
continue;
}
// Put it into the ROM (remember byteswapping)
printf("Patch \"%s\" -> %06X:%04X\n", tok, p.addr, p.data);
rom[p.addr] = (char)(p.data & 0xFF);
rom[p.addr+1] = (char)((p.data & 0xFF00) >> 8);
}
// Done!
free(worklist);
return;
}
// Get/put saveram from/to FILE*'s
void md::get_save_ram(FILE *from)
{
// Pretty simple, just read the saveram raw
fread((void*)saveram, 1, save_len, from);
}
void md::put_save_ram(FILE *into)
{
// Just the opposite of the above :)
fwrite((void*)saveram, 1, save_len, into);
}
// Dave: This is my code, but I thought it belonged here
// Joe: Thanks Dave! No problem ;)
static unsigned short calculate_checksum(unsigned char *rom,int len)
{
unsigned short checksum=0;
int i;
for (i=512;i<=(len-2);i+=2)
{
checksum+=(rom[i+1]<<8);
checksum+=rom[i+0];
}
return checksum;
}
void md::fix_rom_checksum()
{
unsigned short cs; cs=calculate_checksum(rom,romlen);
if (romlen>=0x190) { rom[0x18f]=cs>>8; rom[0x18e]=cs&255; }
}
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