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#include <acpi.h>
#include <stdint.h>
#include <printf.h>
static int RSDP_verify(void *rsdp_pointer) {
printf("Verifying potential RSDP at address 0x%p... ", rsdp_pointer);
union rsdp_t *rsdp = rsdp_pointer;
uint8_t checksum = 0;
char *rsdp_csm_ptr = rsdp_pointer;
int i;
if(checksum) return 0;
if(rsdp->v1.version) {
printf("APCI revision > 2.\n");
checksum = 0;
printf("len : %i\n", rsdp->v2.len);
for(i = 0; i < rsdp->v2.len; i++) {
checksum += rsdp_csm_ptr[i];
}
}
else {
printf("APCI revision 1.\n");
for(i = 0; i <= 20; i++) {
checksum += rsdp_csm_ptr[i];
}
}
if(checksum) {
return 0;
printf("Invalid, searching on.\n");
}
printf("RSDP Verified!\n");
return 1;
}
// TODO: move these when you gain your sanity
rsdp_t *find_RSDP() { // finds root descriptor
const char sig[9] = "RSD PTR ";
uintptr_t *p = (void *)0x040e;
uintptr_t *ebda_unshifted = (void *)p;
// TODO you REALLY need to verify this.
void *ebda = (void *)((uintptr_t)ebda_unshifted << (uintptr_t)4 & (uintptr_t)0xfffff);
for(void *i = ebda; i <= ebda + 64000; i += 16) {
if(!(memcmp(sig, i, 8))) {
if(RSDP_verify(i)) {
return(i);
}
}
}
for(void *i = (void *)0xe0000; i <= (void *)0xfffff; i += 16) {
if(!(memcmp(sig, i, 8))) {
if(RSDP_verify(i)) {
return(i);
}
}
}
}
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