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feat: allow gdb writes to certain mem regions

This commit is contained in:
Rekai Nyangadzayi Musuka 2023-01-29 07:03:46 -06:00
parent e37adbd1f0
commit 3bc04248fb
3 changed files with 101 additions and 55 deletions
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2
lib/zba-gdbstub

@ -1 +1 @@
Subproject commit 82bad92fcf92415f5ee1a1c3c0432c48073a7139
Subproject commit 81ff227ea76d5b44a89e422e380e0fe15aec02aa

148
src/core/Bus.zig
View File

@ -198,55 +198,6 @@ fn fillReadTableExternal(self: *Self, addr: u32) ?*anyopaque {
return &self.pak.buf[masked_addr];
}
pub fn dbgRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
const bits = @typeInfo(std.math.IntFittingRange(0, page_size - 1)).Int.bits;
const page = unaligned_address >> bits;
const offset = unaligned_address & (page_size - 1);
// We're doing some serious out-of-bounds open-bus reads
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
const Ptr = [*]const T;
const ptr = @ptrCast(Ptr, @alignCast(@alignOf(std.meta.Child(Ptr)), some_ptr));
// Note: We don't check array length, since we force align the
// lower bits of the address as the GBA would
return ptr[forceAlign(T, offset) / @sizeOf(T)];
}
return self.dbgSlowRead(T, unaligned_address);
}
fn dbgSlowRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
const page = @truncate(u8, unaligned_address >> 24);
const address = forceAlign(T, unaligned_address);
return switch (page) {
// General Internal Memory
0x00 => blk: {
if (address < Bios.size)
break :blk self.bios.dbgRead(T, self.cpu.r[15], unaligned_address);
break :blk self.openBus(T, address);
},
0x02 => unreachable, // handled by fastmem
0x03 => unreachable, // handled by fastmem
0x04 => self.readIo(T, address),
// Internal Display Memory
0x05 => unreachable, // handled by fastmem
0x06 => unreachable, // handled by fastmem
0x07 => unreachable, // handled by fastmem
// External Memory (Game Pak)
0x08...0x0D => self.pak.dbgRead(T, address),
0x0E...0x0F => self.readBackup(T, unaligned_address),
else => self.openBus(T, address),
};
}
fn readIo(self: *const Self, comptime T: type, address: u32) T {
return io.read(self, T, address) orelse self.openBus(T, address);
}
@ -336,6 +287,27 @@ pub fn read(self: *Self, comptime T: type, unaligned_address: u32) T {
return self.slowRead(T, unaligned_address);
}
pub fn dbgRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
const bits = @typeInfo(std.math.IntFittingRange(0, page_size - 1)).Int.bits;
const page = unaligned_address >> bits;
const offset = unaligned_address & (page_size - 1);
// We're doing some serious out-of-bounds open-bus reads
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
const Ptr = [*]const T;
const ptr = @ptrCast(Ptr, @alignCast(@alignOf(std.meta.Child(Ptr)), some_ptr));
// Note: We don't check array length, since we force align the
// lower bits of the address as the GBA would
return ptr[forceAlign(T, offset) / @sizeOf(T)];
}
return self.dbgSlowRead(T, unaligned_address);
}
fn slowRead(self: *Self, comptime T: type, unaligned_address: u32) T {
@setCold(true);
@ -366,6 +338,34 @@ fn slowRead(self: *Self, comptime T: type, unaligned_address: u32) T {
};
}
fn dbgSlowRead(self: *const Self, comptime T: type, unaligned_address: u32) T {
const page = @truncate(u8, unaligned_address >> 24);
const address = forceAlign(T, unaligned_address);
return switch (page) {
// General Internal Memory
0x00 => blk: {
if (address < Bios.size)
break :blk self.bios.dbgRead(T, self.cpu.r[15], unaligned_address);
break :blk self.openBus(T, address);
},
0x02 => unreachable, // handled by fastmem
0x03 => unreachable, // handled by fastmem
0x04 => self.readIo(T, address),
// Internal Display Memory
0x05 => unreachable, // handled by fastmem
0x06 => unreachable, // handled by fastmem
0x07 => unreachable, // handled by fastmem
// External Memory (Game Pak)
0x08...0x0D => self.pak.dbgRead(T, address),
0x0E...0x0F => self.readBackup(T, unaligned_address),
else => self.openBus(T, address),
};
}
fn readBackup(self: *const Self, comptime T: type, unaligned_address: u32) T {
const value = self.pak.backup.read(unaligned_address);
@ -406,6 +406,31 @@ pub fn write(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
}
}
/// Mostly Identical to `Bus.write`, slowmeme is handled by `Bus.dbgSlowWrite`
pub fn dbgWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) void {
const bits = @typeInfo(std.math.IntFittingRange(0, page_size - 1)).Int.bits;
const page = unaligned_address >> bits;
const offset = unaligned_address & (page_size - 1);
// We're doing some serious out-of-bounds open-bus writes, they do nothing though
if (page >= table_len) return;
if (self.write_tables[@boolToInt(T == u8)][page]) |some_ptr| {
// We have a pointer to a page, cast the pointer to it's underlying type
const Ptr = [*]T;
const ptr = @ptrCast(Ptr, @alignCast(@alignOf(std.meta.Child(Ptr)), some_ptr));
// Note: We don't check array length, since we force align the
// lower bits of the address as the GBA would
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 >> 24) == 0x07) return;
self.dbgSlowWrite(T, unaligned_address, value);
}
}
fn slowWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) void {
@setCold(true);
@ -431,6 +456,31 @@ fn slowWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
}
}
fn dbgSlowWrite(self: *Self, comptime T: type, unaligned_address: u32, value: T) void {
@setCold(true);
const page = @truncate(u8, unaligned_address >> 24);
const address = forceAlign(T, unaligned_address);
switch (page) {
// General Internal Memory
0x00 => self.bios.write(T, address, value),
0x02 => unreachable, // completely handled by fastmem
0x03 => unreachable, // completely handled by fastmem
0x04 => return, // FIXME: Let debug writes mess with I/O
// Internal Display Memory
0x05 => self.ppu.palette.write(T, address, value),
0x06 => self.ppu.vram.write(T, self.ppu.dispcnt, address, value),
0x07 => unreachable, // completely handled by fastmem
// External Memory (Game Pak)
0x08...0x0D => return, // FIXME: Debug Write to Backup/GPIO w/out messing with state
0x0E...0x0F => return, // FIXME: Debug Write to Backup w/out messing with state
else => {},
}
}
inline fn rotateBy(comptime T: type, address: u32) u32 {
return switch (T) {
u32 => address & 3,

6
src/core/emu.zig
View File

@ -184,11 +184,7 @@ pub const EmuThing = struct {
}
pub fn write(self: *Self, addr: u32, value: u8) void {
_ = value;
_ = self;
_ = addr;
std.debug.panic("TODO: Implement Debug Writes?", .{});
self.cpu.bus.dbgWrite(u8, addr, value);
}
pub fn registers(self: *const Self) *[16]u32 {