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fix(bus): resolve simple oversights

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-11-01 09:00:25 -03:00
parent 2851c140ea
commit 505b1b9608
1 changed files with 8 additions and 8 deletions
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16
src/core/Bus.zig
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@ -88,8 +88,8 @@ pub fn init(self: *Self, allocator: Allocator, sched: *Scheduler, cpu: *Arm7tdmi
// Internal Display Memory behavious unusually on 8-bit reads
// so we have two different tables depending on whether there's an 8-bit read or not
fillWriteTable(u16, self, left_write); // T could also be u32 here
fillWriteTable(u8, self, right_write);
fillWriteTable(u8, self, left_write);
fillWriteTable(u32, self, right_write);
}
pub fn deinit(self: *Self) void {
@ -147,7 +147,6 @@ fn fillWriteTable(comptime T: type, bus: *Self, table: *[table_len]?*const anyop
0x0400_0000...0x0400_03FF => null, // I/O
// Internal Display Memory
// FIXME: Different table for different integer width writes?
0x0500_0000...0x05FF_FFFF => if (T != u8) &bus.ppu.palette.buf[addr & 0x3FF] else null,
0x0600_0000...0x06FF_FFFF => if (T != u8) &bus.ppu.vram.buf[vramMirror(addr)] else null,
0x0700_0000...0x07FF_FFFF => if (T != u8) &bus.ppu.oam.buf[addr & 0x3FF] else null,
@ -243,6 +242,7 @@ fn readIo(self: *const Self, comptime T: type, address: u32) T {
}
fn openBus(self: *const Self, comptime T: type, address: u32) T {
@setCold(true);
const r15 = self.cpu.r[15];
const word = blk: {
@ -308,10 +308,10 @@ pub fn read(self: *Self, comptime T: type, unaligned_address: u32) T {
const offset = unaligned_address & (page_size - 1);
// whether or not we do this in slowmem or fastmem, we should advance the scheduler
self.sched.tick += timings[@boolToInt(T == u32)][@truncate(u4, page)];
self.sched.tick += timings[@boolToInt(T == u32)][@truncate(u4, unaligned_address >> 24)];
// We're doing some serious out-of-bounds open-bus reads
if (page > table_len) return self.slowRead(T, unaligned_address);
if (page > table_len) return self.openBus(T, unaligned_address);
if (self.read_table[page]) |some_ptr| {
// We have a pointer to a page, cast the pointer to it's underlying type
@ -374,12 +374,12 @@ pub fn write(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
const offset = unaligned_address & (page_size - 1);
// whether or not we do this in slowmem or fastmem, we should advance the scheduler
self.sched.tick += timings[@boolToInt(T == u32)][@truncate(u4, page)];
self.sched.tick += timings[@boolToInt(T == u32)][@truncate(u4, unaligned_address >> 24)];
// We're doing some serious out-of-bounds open-bus writes, they do nothing though
if (page > table_len) return;
if (self.write_tables[if (T == u8) 1 else 0][page]) |some_ptr| {
if (self.write_tables[@boolToInt(T == u32)][page]) |some_ptr| {
// We have a pointer to a page, cast the pointer to it's underlying type
const Ptr = [*]T;
const alignment = @alignOf(std.meta.Child(Ptr));
@ -390,7 +390,7 @@ pub fn write(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
ptr[forceAlign(T, offset) / @sizeOf(T)] = value;
} else {
// we can return early if this is an 8-bit OAM write
if (T == u8 and @truncate(u8, unaligned_address) == 0x07) return;
if (T == u8 and @truncate(u8, unaligned_address >> 24) == 0x07) return;
self.slowWrite(T, unaligned_address, value);
}