52 lines
1.4 KiB
Zig
52 lines
1.4 KiB
Zig
const std = @import("std");
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const Allocator = std.mem.Allocator;
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const buf_len = 0x400;
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const Self = @This();
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buf: []u8,
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allocator: Allocator,
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pub fn read(self: *const Self, comptime T: type, address: usize) T {
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const addr = address & 0x3FF;
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return switch (T) {
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u32, u16, u8 => std.mem.readIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)]),
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else => @compileError("PALRAM: Unsupported read width"),
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};
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}
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pub fn write(self: *Self, comptime T: type, address: usize, value: T) void {
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const addr = address & 0x3FF;
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switch (T) {
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u32, u16 => std.mem.writeIntSliceLittle(T, self.buf[addr..][0..@sizeOf(T)], value),
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u8 => {
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const align_addr = addr & ~@as(u32, 1); // Aligned to Halfword boundary
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std.mem.writeIntSliceLittle(u16, self.buf[align_addr..][0..@sizeOf(u16)], @as(u16, value) * 0x101);
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},
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else => @compileError("PALRAM: Unsupported write width"),
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}
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}
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pub fn init(allocator: Allocator) !Self {
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const buf = try allocator.alloc(u8, buf_len);
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@memset(buf, 0);
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return Self{ .buf = buf, .allocator = allocator };
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}
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pub fn reset(self: *Self) void {
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@memset(self.buf, 0);
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}
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pub fn deinit(self: *Self) void {
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self.allocator.free(self.buf);
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self.* = undefined;
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}
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pub inline fn backdrop(self: *const Self) u16 {
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return std.mem.readIntNative(u16, self.buf[0..2]);
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}
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