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56 lines
1.8 KiB
Zig
56 lines
1.8 KiB
Zig
const std = @import("std");
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const assert = std.debug.assert;
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pub fn Mmio(comptime PackedT: type) type {
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const size = @bitSizeOf(PackedT);
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if ((size % 8) != 0)
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@compileError("size must be divisible by 8!");
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if (!std.math.isPowerOfTwo(size / 8))
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@compileError("size must encode a power of two number of bytes!");
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const IntT = std.meta.Int(.unsigned, size);
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if (@sizeOf(PackedT) != (size / 8))
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@compileError(std.fmt.comptimePrint("IntT and PackedT must have the same size!, they are {} and {} bytes respectively", .{ size / 8, @sizeOf(PackedT) }));
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return extern struct {
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const Self = @This();
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raw: IntT,
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pub const underlying_type = PackedT;
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pub inline fn read(addr: *volatile Self) PackedT {
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return @bitCast(addr.raw);
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}
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pub inline fn write(addr: *volatile Self, val: PackedT) void {
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comptime {
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assert(@bitSizeOf(PackedT) == @bitSizeOf(IntT));
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}
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addr.write_raw(@bitCast(val));
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}
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pub fn write_raw(addr: *volatile Self, val: IntT) void {
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addr.raw = val;
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}
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pub inline fn modify(addr: *volatile Self, fields: anytype) void {
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var val = read(addr);
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inline for (@typeInfo(@TypeOf(fields)).Struct.fields) |field| {
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@field(val, field.name) = @field(fields, field.name);
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}
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write(addr, val);
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}
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pub inline fn toggle(addr: *volatile Self, fields: anytype) void {
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var val = read(addr);
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inline for (@typeInfo(@TypeOf(fields)).Struct.fields) |field| {
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@field(val, @tagName(field.default_value.?)) = !@field(val, @tagName(field.default_value.?));
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}
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write(addr, val);
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}
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};
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}
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