Does Move to/from Control/Debug Registers ignore the field mod?
Summary In x86/64 architecture, the MOV to/from control/debug registers (0F 20 /r, 0F 22 /r) treat the ModR/M byte as purely register-to-register, regardless of the mod field. The mod field (bits 7-6) is ignored (effectively treated as mod=11), and no displacement bytes follow the ModR/M byte. Any attempt to encode a displacement (e.g., mod=01 or … Read more