zig/src-self-hosted/codegen/x86.zig

31 lines
902 B
Zig

// zig fmt: off
pub const Register = enum(u8) {
// 0 through 7, 32-bit registers. id is int value
eax, ecx, edx, ebx, esp, ebp, esi, edi,
// 8-15, 16-bit registers. id is int value - 8.
ax, cx, dx, bx, sp, bp, si, di,
// 16-23, 8-bit registers. id is int value - 16.
al, bl, cl, dl, ah, ch, dh, bh,
/// Returns the bit-width of the register.
pub fn size(self: @This()) u7 {
return switch (@enumToInt(self)) {
0...7 => 32,
8...15 => 16,
16...23 => 8,
else => unreachable,
};
}
/// Returns the register's id. This is used in practically every opcode the
/// x86 has. It is embedded in some instructions, such as the `B8 +rd` move
/// instruction, and is used in the R/M byte.
pub fn id(self: @This()) u3 {
return @truncate(u3, @enumToInt(self));
}
};
// zig fmt: on