53 lines
1.5 KiB
Zig
53 lines
1.5 KiB
Zig
const std = @import("std");
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const Allocator = std.mem.Allocator;
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const log = std.log.scoped(.Bios);
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/// Size of the BIOS in bytes
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pub const size = 0x4000;
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const Self = @This();
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buf: ?[]u8,
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alloc: Allocator,
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pub fn init(alloc: Allocator, maybe_path: ?[]const u8) !Self {
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var buf: ?[]u8 = null;
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if (maybe_path) |path| {
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const file = try std.fs.cwd().openFile(path, .{});
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defer file.close();
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buf = try file.readToEndAlloc(alloc, try file.getEndPos());
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}
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return Self{
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.buf = buf,
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.alloc = alloc,
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};
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}
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pub fn deinit(self: Self) void {
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if (self.buf) |buf| self.alloc.free(buf);
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}
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pub fn read(self: *const Self, comptime T: type, addr: usize) T {
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if (self.buf) |buf| {
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if (addr > buf.len) {
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log.debug("Tried to read {} from {X:0>8} (open bus)", .{ T, addr });
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return 0;
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}
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return switch (T) {
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u32 => (@as(u32, buf[addr + 3]) << 24) | (@as(u32, buf[addr + 2]) << 16) | (@as(u32, buf[addr + 1]) << 8) | (@as(u32, buf[addr])),
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u16 => (@as(u16, buf[addr + 1]) << 8) | @as(u16, buf[addr]),
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u8 => buf[addr],
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else => @compileError("BIOS: Unsupported read width"),
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};
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}
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std.debug.panic("[BIOS] ZBA tried to read {} from 0x{X:0>8} but not BIOS was present", .{ T, addr });
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}
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pub fn write(_: *Self, comptime T: type, addr: usize, value: T) void {
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@setCold(true);
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log.debug("Tried to write {} 0x{X:} to 0x{X:0>8} ", .{ T, value, addr });
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}
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