void*
sigsearch(char* signature)
{
uintptr p;
uchar *bda;
void *r;
/*
* Search for the data structure:
* 1) within the first KiB of the Extended BIOS Data Area (EBDA), or
* 2) within the last KiB of system base memory if the EBDA segment
* is undefined, or
* 3) within the BIOS ROM address space between 0xf0000 and 0xfffff
* (but will actually check 0xe0000 to 0xfffff).
*/
bda = BIOSSEG(0x40);
if(memcmp(KADDR(0xfffd9), "EISA", 4) == 0){
if((p = (bda[0x0f]<<8)|bda[0x0e]) != 0){
if((r = sigscan(BIOSSEG(p), 1024, signature)) != nil)
return r;
}
}
if((p = ((bda[0x14]<<8)|bda[0x13])*1024) != 0){
if((r = sigscan(KADDR(p-1024), 1024, signature)) != nil)
return r;
}
/* hack for virtualbox: look in KiB below 0xa0000 */
if((r = sigscan(KADDR(0xa0000-1024), 1024, signature)) != nil)
return r;
return sigscan(BIOSSEG(0xe000), 0x20000, signature);
}
static void*
rsdsearch(char* signature)
{
uintptr_t p;
uint8_t *bda;
void *rsd;
/*
* Search for the data structure signature:
* 1) in the first KB of the EBDA;
* 2) in the BIOS ROM between 0xE0000 and 0xFFFFF.
*/
if(strncmp((char*)KADDR(0xFFFD9), "EISA", 4) == 0){
bda = BIOSSEG(0x40);
if((p = (bda[0x0F]<<8)|bda[0x0E])){
if(rsd = rsdscan(KADDR(p), 1024, signature))
return rsd;
}
}
return rsdscan(BIOSSEG(0xE000), 0x20000, signature);
}