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feat(ppu): implement VRAM

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-01-03 19:47:26 -06:00
parent 1d4ba2e2b3
commit 8257a3899a
2 changed files with 58 additions and 8 deletions
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19
src/bus.zig
View File

@ -3,18 +3,21 @@ const std = @import("std");
const Io = @import("bus/io.zig").Io;
const Bios = @import("bus/bios.zig").Bios;
const GamePak = @import("bus/pak.zig").GamePak;
const Ppu = @import("ppu.zig").Ppu;
const Allocator = std.mem.Allocator;
pub const Bus = struct {
pak: GamePak,
bios: Bios,
ppu: Ppu,
io: Io,
pub fn init(alloc: Allocator, path: []const u8) !@This() {
return @This(){
.pak = try GamePak.init(alloc, path),
// TODO: don't hardcode this + bundle open-sorce Boot ROM
.bios = try Bios.init(alloc, "./bin/gba_bios.bin"),
.bios = try Bios.init(alloc, "./bin/gba_bios.bin"), // TODO: don't hardcode this + bundle open-sorce Boot ROM
.ppu = try Ppu.init(alloc),
.io = Io.init(),
};
}
@ -29,7 +32,7 @@ pub const Bus = struct {
// Internal Display Memory
0x0500_0000...0x0500_03FF => std.debug.panic("[Bus:32] read from 0x{X:} in BG/OBJ Palette RAM", .{addr}),
0x0600_0000...0x0601_7FFF => std.debug.panic("[Bus:32] read from 0x{X:} in VRAM", .{addr}),
0x0600_0000...0x0601_7FFF => self.ppu.vram.get32(@as(usize, addr - 0x0600_0000)),
0x0700_0000...0x0700_03FF => std.debug.panic("[Bus:32] read from 0x{X:} in OAM", .{addr}),
// External Memory (Game Pak)
@ -44,7 +47,7 @@ pub const Bus = struct {
};
}
pub fn write32(_: *@This(), addr: u32, word: u32) void {
pub fn write32(self: *@This(), addr: u32, word: u32) void {
// TODO: write32 can write to GamePak Flash
switch (addr) {
@ -55,7 +58,7 @@ pub const Bus = struct {
// Internal Display Memory
0x0500_0000...0x0500_03FF => std.debug.panic("[Bus:32] wrote 0x{X:} to 0x{X:} in BG/OBJ Palette RAM", .{ word, addr }),
0x0600_0000...0x0601_7FFF => std.debug.panic("[Bus:32] wrote 0x{X:} to 0x{X:} in VRAM", .{ word, addr }),
0x0600_0000...0x0601_7FFF => self.ppu.vram.set32(@as(usize, addr - 0x0600_0000), word),
0x0700_0000...0x0700_03FF => std.debug.panic("[Bus:32] wrote 0x{X:} to 0x{X:} in OAM", .{ word, addr }),
else => std.log.warn("[Bus:32] ZBA tried to write 0x{X:} to 0x{X:}", .{ word, addr }),
@ -72,7 +75,7 @@ pub const Bus = struct {
// Internal Display Memory
0x0500_0000...0x0500_03FF => std.debug.panic("[Bus:16] read from 0x{X:} in BG/OBJ Palette RAM", .{addr}),
0x0600_0000...0x0601_7FFF => std.debug.panic("[Bus:16] read from 0x{X:} in VRAM", .{addr}),
0x0600_0000...0x0601_7FFF => self.ppu.vram.get16(@as(usize, addr - 0x0600_0000)),
0x0700_0000...0x0700_03FF => std.debug.panic("[Bus:16] read from 0x{X:} in OAM", .{addr}),
// External Memory (Game Pak)
@ -98,7 +101,7 @@ pub const Bus = struct {
// Internal Display Memory
0x0500_0000...0x0500_03FF => std.debug.panic("[Bus:16] write 0x{X:} to 0x{X:} in BG/OBJ Palette RAM", .{ halfword, addr }),
0x0600_0000...0x0601_7FFF => std.debug.panic("[Bus:16] write 0x{X:} to 0x{X:} in VRAM", .{ halfword, addr }),
0x0600_0000...0x0601_7FFF => self.ppu.vram.set16(@as(usize, addr - 0x0600_0000), halfword),
0x0700_0000...0x0700_03FF => std.debug.panic("[Bus:16] write 0x{X:} to 0x{X:} in OAM", .{ halfword, addr }),
else => std.log.warn("[Bus:16] ZBA tried to write 0x{X:} to 0x{X:}", .{ halfword, addr }),
@ -115,7 +118,7 @@ pub const Bus = struct {
// Internal Display Memory
0x0500_0000...0x0500_03FF => std.debug.panic("[Bus:8] read from 0x{X:} in BG/OBJ Palette RAM", .{addr}),
0x0600_0000...0x0601_7FFF => std.debug.panic("[Bus:8] read from 0x{X:} in VRAM", .{addr}),
0x0600_0000...0x0601_7FFF => self.ppu.vram.get8(@as(usize, addr - 0x0600_0000)),
0x0700_0000...0x0700_03FF => std.debug.panic("[Bus:8] read from 0x{X:} in OAM", .{addr}),
// External Memory (Game Pak)

47
src/ppu.zig Normal file
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@ -0,0 +1,47 @@
const std = @import("std");
const Allocator = std.mem.Allocator;
pub const Ppu = struct {
vram: Vram,
pub fn init(alloc: Allocator) !@This() {
return @This(){
.vram = try Vram.init(alloc),
};
}
};
const Vram = struct {
buf: []u8,
fn init(alloc: Allocator) !@This() {
return @This(){
.buf = try alloc.alloc(u8, 0x18000),
};
}
pub inline fn get32(self: *const @This(), idx: usize) u32 {
return (@as(u32, self.buf[idx + 3]) << 24) | (@as(u32, self.buf[idx + 2]) << 16) | (@as(u32, self.buf[idx + 1]) << 8) | (@as(u32, self.buf[idx]));
}
pub inline fn set32(self: *@This(), idx: usize, word: u32) void {
self.buf[idx + 3] = @truncate(u8, word >> 24);
self.buf[idx + 2] = @truncate(u8, word >> 16);
self.buf[idx + 1] = @truncate(u8, word >> 8);
self.buf[idx] = @truncate(u8, word);
}
pub inline fn get16(self: *const @This(), idx: usize) u16 {
return (@as(u16, self.buf[idx + 1]) << 8) | @as(u16, self.buf[idx]);
}
pub inline fn set16(self: *@This(), idx: usize, halfword: u16) void {
self.buf[idx + 1] = @truncate(u8, halfword >> 8);
self.buf[idx] = @truncate(u8, halfword);
}
pub inline fn get8(self: *const @This(), idx: usize) u8 {
return self.buf[idx];
}
};