6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2025-01-11 08:30:55 +00:00
Code Issues Projects Releases Wiki Activity

Ensures the Commodore parser properly rejects non-GCR disks.

Browse Source
This commit is contained in:
Thomas Harte 2018-03-22 20:23:21 -04:00
parent 34cc39ad65
commit 0fdbbeca1d
1 changed files with 11 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
Analyser/Static/Commodore/Disk.cpp
View File

@ -71,19 +71,19 @@ class CommodoreGCRParser: public Storage::Disk::Controller {
bit_count_++;
}
unsigned int proceed_to_next_block() {
unsigned int proceed_to_next_block(int max_index_count) {
// find GCR lead-in
proceed_to_shift_value(0x3ff);
if(shift_register_ != 0x3ff) return 0xff;
// find end of lead-in
while(shift_register_ == 0x3ff && index_count_ < 2) {
while(shift_register_ == 0x3ff && index_count_ < max_index_count) {
run_for(Cycles(1));
}
// continue for a further nine bits
bit_count_ = 0;
while(bit_count_ < 9 && index_count_ < 2) {
while(bit_count_ < 9 && index_count_ < max_index_count) {
run_for(Cycles(1));
}
@ -97,8 +97,8 @@ class CommodoreGCRParser: public Storage::Disk::Controller {
}
void proceed_to_shift_value(unsigned int shift_value) {
index_count_ = 0;
while(shift_register_ != shift_value && index_count_ < 2) {
const int max_index_count = index_count_ + 2;
while(shift_register_ != shift_value && index_count_ < max_index_count) {
run_for(Cycles(1));
}
}
@ -124,13 +124,13 @@ class CommodoreGCRParser: public Storage::Disk::Controller {
std::shared_ptr<Sector> get_next_sector() {
std::shared_ptr<Sector> sector(new Sector);
index_count_ = 0;
const int max_index_count = index_count_ + 2;
while(index_count_ < 2) {
while(index_count_ < max_index_count) {
// look for a sector header
while(1) {
if(proceed_to_next_block() == 0x08) break;
if(index_count_ >= 2) return nullptr;
if(proceed_to_next_block(max_index_count) == 0x08) break;
if(index_count_ >= max_index_count) return nullptr;
}
// get sector details, skip if this looks malformed
@ -144,8 +144,8 @@ class CommodoreGCRParser: public Storage::Disk::Controller {
// look for the following data
while(1) {
if(proceed_to_next_block() == 0x07) break;
if(index_count_ >= 2) return nullptr;
if(proceed_to_next_block(max_index_count) == 0x07) break;
if(index_count_ >= max_index_count) return nullptr;
}
checksum = 0;